australian earthquake fault plane solutionsaustralian earthquake fault plane solutions leonard, m.,...

Australian earthquakefault plane solutions

Leonard, M., Ripper, I.D. & Yue, L.

A U S T R A L I AGEOSCIENCE

Record 2002/19

S P A T I A L I N F O R M A T I O N F O R T H E N A T I O N

G E O S C I E N C E A U S T R A L I A

GEOSCIENCE AUSTRALIA DEPARTMENT OF INDUSTRY, TOURISM & RESOURCES

Geoscience Australia Record 2002/19

AUSTRALIAN EARTHQUAKE FAULT PLANE SOLUTIONS

Leonard, M., Ripper, I.D. & Yue, L.

Minerals & Geohazards Division, Geoscience Australia,GPO Box 378, Canberra, ACT 2601

CANBERRA 2002

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Geoscience Australia

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© Commonwealth of Australia 2003

This work is copyright. Apart from any fair dealings for the purposes of study,research, criticism or review, as permitted under the Copyright Act, no part may bereproduced by any process without written permission. Inquiries should be directed tothe Communications Unit, Geoscience Australia, GPO Box 378, Canberra City, ACT,2601

ISSN: 1039-0073 ISBN: 0 642 46748 X

Bibliographic reference: Leonard, M., Ripper, I.D. & Yue, L. 2002.Australian earthquake fault plane solutions. Geoscience Australia, Record 2002/19.

Geoscience Australia has tried to make the information in this product as accurate aspossible. However, it does not guarantee that the information is totally accurate orcomplete. THEREFORE, YOU SHOULD NOT RELY SOLELY ON THISINFORMATION WHEN MAKING A COMMERCIAL DECISION

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Australian earthquake fault plane solutions

Mark Leonard, Ian D. Ripper, and Li Yue

AUSTRALIAN EARTHQUAKE FAULT PLANE SOLUTIONS .....................................................................................1

ABSTRACT ............................................................................................................................................................................4

INTRODUCTION ..................................................................................................................................................................4

THE RATING SCHEMES ....................................................................................................................................................5

DERIVING STRESS DATA FROM EARTHQUAKES (FROM CLARK & LEONARD, 2003)...................................6

THE EARTHQUAKE SOLUTIONS....................................................................................................................................7

BERRIDALE, 18TH MAY 1959 .................................................................................................................................................7ROBERTSON 21ST MAY 1961..................................................................................................................................................8MT HOTHAM, 3RD MAY 1966.................................................................................................................................................9MECKERING, 14TH OCTOBER................................................................................................................................................10CALINGIRI, 10TH MARCH 1970.............................................................................................................................................13LAKE MACKAY, 24TH MARCH 1970 ....................................................................................................................................14MIDDLINGBANK, 21ST JUNE 1971 ........................................................................................................................................17DALTON, 3RD NOVEMBER 1971............................................................................................................................................18TEMORA, 25TH FEBRUARY 1972...........................................................................................................................................19SIMPSON DESERT, 28TH AUGUST 1972.................................................................................................................................20GUNNING, 8TH JANUARY 1973 .............................................................................................................................................22PICTON, 9TH MARCH 1973....................................................................................................................................................23GUNNING, 22 MARCH 1974.................................................................................................................................................25MURRUMBATEMAN, 6TH MAY 1974.....................................................................................................................................26GUNNING, 4TH AUGUST 1975 ...............................................................................................................................................27THE PILOT, 8TH SEPTEMBER 1976 ........................................................................................................................................28DALTON, 5TH APRIL 1977.....................................................................................................................................................29QUORN, 16TH APRIL 1977 ....................................................................................................................................................30BOWNING, 30TH JUNE 1977 ..................................................................................................................................................31BOWNING, 4TH JULY 1977 ..................................................................................................................................................33BLINMAN, 30TH AUGUST 1977 .............................................................................................................................................34MELTON, 28TH SEPTEMBER 1977 .........................................................................................................................................35BALLING, 2ND DECEMBER 1977 ...........................................................................................................................................36CARRIETON, 26 MARCH 1978 .............................................................................................................................................38HALLS CREEK, 6TH MAY 1978 .............................................................................................................................................39SIMPSON DESERT, 25TH NOVEMBER 1978............................................................................................................................40BROOME, 23RD APRIL 1979..................................................................................................................................................42CADOUX, 2ND JUNE 1979 .....................................................................................................................................................43BROOME, 14TH JULY 1979....................................................................................................................................................45HAWKER, 22ND APRIL 1980 .................................................................................................................................................46WILPENA, 15TH JULY 1981...................................................................................................................................................47APPIN, 15TH NOVEMBER 1981..............................................................................................................................................48SUGGAN BUGGAN, 30TH NOVEMBER 1981...........................................................................................................................49WONNANGATTA, 21ST NOVEMBER 1982 ..............................................................................................................................50WEST WYALONG, 26 NOVEMBER 1982...............................................................................................................................51TASMAN SEA, 25TH NOVEMBER 1983 ..................................................................................................................................52BELTANA, 29TH DECEMBER 1983.........................................................................................................................................55OOLONG, 9TH AUGUST 1984 ................................................................................................................................................56LAKE FROME, 28TH MAY 1985.............................................................................................................................................57NORSEMAN, 28TH JULY 1985 ...............................................................................................................................................58CANBERRA, 28TH NOVEMBER 1985......................................................................................................................................59

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COLO, 20TH FEBRUARY 1986 ...............................................................................................................................................60MARRYAT CREEK, 30TH MARCH 1986 .................................................................................................................................61MARRYAT CREEK, 11 JULY 1986 ........................................................................................................................................63TENNANT CREEK, 9TH JANUARY 1987..................................................................................................................................65CADOUX, 7TH MARCH 1987 .................................................................................................................................................66LITHGOW, 24TH JUNE 1987...................................................................................................................................................67NHILL, 22ND DECEMBER 1987..............................................................................................................................................68TENNANT CREEK, 22ND JANUARY 1988 ...............................................................................................................................69TENNANT CREEK, 22ND JANUARY 1988 ...............................................................................................................................71TENNANT CREEK, 22ND JANUARY 1988 ...............................................................................................................................73TENNANT CREEK, 22ND JANUARY 1988 ...............................................................................................................................75DOUBTFUL BAY, 6TH FEBRUARY 1988 .................................................................................................................................77BUNNALOO, 3RD JULY 1988 .................................................................................................................................................79ULURU, 28 MAY 1989.........................................................................................................................................................80BEAGLE BAY, 13TH OCTOBER 1989 .....................................................................................................................................81NEWCASTLE, 28TH DECEMBER 1989 ....................................................................................................................................82MECKERING, 17TH JANUARY 1990 .......................................................................................................................................83WOODS REEF, 14TH NOVEMBER 1990 ..................................................................................................................................84BAJOOL, 10TH JUNE 1991 .....................................................................................................................................................85TENNANT CREEK 19TH JUNE 1991........................................................................................................................................86TENNANT CREEK, 8TH JULY 1991.........................................................................................................................................87MORALANA, FEBRUARY 1992............................................................................................................................................88ELLALONG, 6TH AUGUST 1994 .............................................................................................................................................90SOUTHERN OCEAN, 15TH MAY 1995 ....................................................................................................................................91WHITE CLIFFS, 13TH AUGUST 1996......................................................................................................................................92THOMSON DAM, 25TH SEPTEMBER 1996 ..............................................................................................................................93BURRA, 5TH MARCH 1997 ....................................................................................................................................................94COLLIER BAY, 10TH AUGUST 1997 ......................................................................................................................................96TENNANT CREEK 15TH APRIL 1999 ......................................................................................................................................97BOOLARRA SOUTH, 29TH AUGUST 2000...............................................................................................................................98EXMOUTH PLATEAU, 11TH OCTOBER 2000 ..........................................................................................................................99DUMBALK, 30TH OCTOBER 2000........................................................................................................................................100BOOLARRA SOUTH, 4TH JULY 2001 ....................................................................................................................................101BURAKIN, SEPTEMBER 28TH 2001 ......................................................................................................................................102RAVENSTHORPE, OCTOBER 19TH 2001...............................................................................................................................103BURAKIN DECEMBER 25TH 2001 ........................................................................................................................................104BURAKIN DECEMBER 25TH 2001 ........................................................................................................................................105BURAKIN MARCH 5TH 2002................................................................................................................................................106BURAKIN MARCH 5TH 2002................................................................................................................................................107BURAKIN MARCH 23RD 2002..............................................................................................................................................108BURAKIN MARCH 30TH 2002..............................................................................................................................................109SUTTON SWARM DECEMBER 2001 – APRIL 2002 ..............................................................................................................110

REFERENCES ...................................................................................................................................................................111

TABLE OF FAULT PLANE SOLUTIONS .................................................................................... see Text files directory

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Figure 1 Location of the 84 earthquakes which have Focal Plane Solutions.

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Abstract

This Atlas of focal plane solutions of Australian earthquakes contains the focal mechanisms of all known Australianearthquakes for which a mechanism has been determined. A total of 107 Focal Plane Solutions (FPS) are presented for 84earthquakes in Australia and the surrounding region. The earthquakes are presented in chronological order and for eachearthquake the hypocentre, magnitude, focal plane solution and a picture is given. Where available additional comments areincluded as is the data used to determine the mechanism (typically first motion data). This is the first time mechanisms forAustralian earthquakes have been compiled into an atlas.

Two quality ranking schemes are used in this atlas. One is the Zoback (1992) rating which is a measure of the tectonicstress information that may be obtained, not the quality of the earthquake focal mechanism. The second devised by Leonardand Ripper, is essentially a measure of how well the N axis is constrained.

The majority of the mechanisms have been derived from the analysis of first motions with many of the larger events since1980 having moment tensor solutions. Of the 84 earthquakes analysed 70 are thrust events, 12 are strike slip and 2 arenormal mechanisms. This is consistent with a model of generally compressional stress in Australia.

IntroductionBy studying the seismic waves from an earthquake arriving at a variety of seismograph stations distributed over the Earth’ssurface, the type of earthquake (thrust, strike-slip or normal) and the geometry of the fault plane can often be determined.The most common method of achieving this is by plotting the initial direction of movement, or polarity, of the P phase ontoan equal area stereographic projection, using the azimuth of each station from the epicentre, together with the angle ofdeparture from the vertical of the direct ray from the source to the station, (for a detailed treatment of this process seeFowler, 1990, pp.97–104). Regions of positive and negative polarity are then separated into quadrants by two mutuallyorthogonal nodal planes, one of which represents the fault plane and the other an auxiliary plane. Without additionalinformation (eg fault scarp, geology, geophysics or tectonics) it will not normally be possible to determine which plane isthe fault plane. The resulting diagram is known as a focal plane solution, or focal mechanism. The line bisecting thedilative dihedron of a focal mechanism is denoted the P-kinematic axis and the line bisecting the compressive dihedron theT-kinematic axis. These axes, and the line of intersection of the nodal planes (B axis), correspond very crudely to the σ1,σ3 and σ2 principal stress axes respectively.

In general, the greater the number of stations recording an event, the more precise the resulting focal mechanism will be,and the better the stress data which may be derived from it. In Australia, sufficient data to determine the focal mechanismsis generally only available for earthquakes with magnitudes greater than 4.0 (the Flinders Ranges in South Australia andsoutheastern Victoria are exceptions). Consequently, earthquakes with magnitudes greater than 4.0 comprise over 70% ofcompiled mechanisms. The magnitude distribution also varies with time, with larger events featuring more prominently inthe early days when the seismographic network was not as extensive as today

The majority of Australian earthquake fault plane solutions, in this atlas, have been evaluated from the published faultplane solutions. There has been little access to original datasets, so these datasets could not be manipulated. Typically theinformation needed to reconstruct the fault plane solutions is not known. This includes:Station names are often not shown on the projection diagrams. The author's understanding of relative station reliability is not known. The relative amplitudes of the P waves is not known. The impulsive/emergent P wave arrival characteristics are generally not known. Why this station’s polarity was included and that station’s polarity was ignored is generally not clear. The velocity model used to calculate the angle of departure is unknown. Many earthquakes have several solutions and the criteria by which one solution is chosen over the possible alternatives isnot clear – often there is an implicit assumption that stress in Australia is compressive so the solution which fits this modelis chosen.

Re-evaluation of original seismograms would be a mammoth task, as not only the records of Geoscience Australia’sstations would need to be retrieved from archives, but also those of other institutions. Relocation of the earthquake,especially its depth in the crustal model, would also need to be undertaken.

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The strikes and dips in this atlas use the right hand rule with strike ranging from 0 to 359 degrees and dip from 0 to 90degrees. Many of the original solutions did not use this convention, in which case we have converted the original valuesinto this convention.

In addition to first motion other information in the seismogram can be used to derive the focal plan solutions. Fitch et al.(1973) used S wave polarisation directions to assist in determination of the fault plane configuration. Ripper (1971) notedthat S wave polarisation directions converge on either the Pressure(P) and Tension(T) axes or are parallel to the fault planeconverging on the slip vector in the fault plane. The seismic phase amplitude ratio method used by Bock (1993) comparesseismic phase amplitudes (Pn etc) of regional seismic station seismograms with synthetic seismograms and minimises thedifferences. The ration of SV to P can also be used to constrain the focal mechanism (Snoke et al. 1984), though thisappears not to have been used in any of the focal mechanisms in this atlas.

The Harvard University Seismology Group, Department of Earth and Planetary Sciences, has now provided the largest andmost consistent global earthquake focal mechanism database. The centroid moment tensor solutions are derived by themethod described by Dziewonski, Chou and Woodhouse (1981) and utilize the whole P waveform rather than just the Pwave first motion. The solutions are routinely computed by Harvard on a global basis, starting in 1976. They have beenpublished since 1981 by the United States Geological Survey in their Weekly and Monthly Listings, in addition to theUSGS (moment tensor solutions) and the International Seismological Centre. They are also published by Harvard on aregular basis, for example, Dziewonski et al.(1991) and are available on the Harvard Seismology website. The beachballswhich appear in the Harvard earthquake centroid moment tensor solutions are the full solutions, not the orthogonal nodalplane approximations, although the nodal plane parameters are also given

Harvard earthquake centroid moment tensor solutions date from 1976 and solutions for most earthquakes above magnitude5 have been computed. Several Australian moment tensor solutions have been computed, but with notable exceptions, suchas the 1989 Newcastle earthquake. These are included in this atlas.

As mentioned in (7) above, many of the scientists who produce fault plane solutions assume that Australia is undercompressive stress (probably true) and so when there is a choice between reverse, strike slip and normal, the reverse (1st

preference) or strike slip (2nd preference) are typically chosen. Where possible the alternatives have been identified, even ifthe original author only published the preferred solution. Care needs to be taken when using these events in stress studies.

The Rating Schemes

Zoback(1992) rating. Quality ranking system for stress orientations, derived from earthquake focal mechanisms solutions.The rating is not a measure of the quality of the earthquake focal mechanism itself, but of the tectonic stress informationthat may be obtained from it.

A Average P axis or formal inversion of four or more single event solutions in close geographic proximity (at leastone event M≥4.0, other events M≥3.0 ).

B Well constrained single event solution ( M≥4.5 ) or average of two well constrained single event solutions (M≥3.5) determined from first motions and other methods ( eg, moment tensor waveform modelling or inversion ).

C Single event solution (constrained by first motions only, often based on author's quality assignment; M≥2.5; oraverage of several well constrained composites (M>2 ), and Moment Tensor solutions.

D Single composite solution; or poorly constrained single event solution; or single event solution for M<2.5 event.

E Large historic event with no reliable focal mechanism; or event with P,T,B axes all plunging 25°-40°; or eventwith P and T axes both plunging 40°-50°.

X Not rated

Fault Plane Ratings. These ratings were developed by Leonard and Ripper for this atlas. They are intended as a measureof the quality of the earthquake focal mechanism determination itself.

Tight.

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Some uncertainty as solution too tight with overlapping polarities, non-orthogonal.

Well constrained, uncertainty of N (B) axis less than about 15° by 15°, either from the polarity data or by the inclusion ofsome additional information. Moment Tensor solutions.

Reasonably constrained, uncertainty of N axis less than about 30° by 30°, either from the polarity data or by the inclusionof some additional information.

Poorly constrained, uncertainty of N axis greater than about 30° by 30°.

X Not rated

Zoback(1992), on moment tensor solutions, noted that Centroid Moment Tensor (CMT) solutions by Harvard are assignedC quality if there is no additional study of the event, and this lower quality, despite magnitudes being generally greater than5, is due to the poor resolution of the CMT inversion for the vertical dipslip components of faulting in shallow focusevents. Zoback also referred to a comparison of Harvard CMT solutions with World Wide Standard Seismograph P wavepolarity solutions which found that, of 20 solutions examined, two were incompatible. Hence in the ratings of fault planesolution quality, moment tensor solutions are also rated midway, 3.

Deriving stress data from earthquakes (from Clark & Leonard, 2003)The line bisecting the dilative dihedron of a focal mechanism is denoted the P-kinematic axis and the line bisecting thecompressive dihedron the T-kinematic axis. These axes, and the line of intersection of the nodal planes (B axis),correspond very crudely to the σ1, σ3 and σ2 principal stress axes respectively (cf. Ramsay & Huber, 1983), and therebyprovide stress information. However, a one-to-one correlation is not possible as intact rock does not fracture at 45 degreesto the principle stresses (for typical coefficients of internal friction the angle is between 20-40 degrees), and movementalong a pre-existing fault would be influenced by static friction.McKenzie (1969) showed that the maximum compressive stress could have an orientation anywhere within the dilatationalquadrants of a focal mechanism, as slip can occur on pre-existing planes of weakness. Hence, the principal stress directionsare poorly constrained by a single fault plane solution, and more importantly, by any number of P and T axis orientations.If, however, more than four different focal mechanisms occur within a region of uniform stress, then both the principalstress directions (σ1>σ2>σ3 with compression positive) and a measure of the relative stress magnitudes (R = (σ2-σ3)/(σ1-σ3)) may be determined (e.g. Bott, 1959; Angelier, 1979; Célérier, 1988). Standard procedures are now well establishedfor stress tensor reconstruction from fault-slip data using both numerical techniques and/or graphical techniques – see Clarkand Leonard (2003) for a list of references on these techniques. The fundamental assumption underpinning all thesemethods is the premise that in a body of rock under stress, slip on a plane occurs in the direction of maximum resolvedshear stress (Wallace, 1951; Bott, 1959). Further assumptions are that stress is homogeneous and faults do not interactmechanically.

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The earthquake solutionsBerridale, 18th May 1959Date :1959 May 18Place :Berridale, southeast NSW, Bega 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981); Cleary et al.(1964).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt Projection.Magnitudes :ML 5.2; MS 3.8Origin time (UTC) :061259.3Hypocentre, Latitude:-36.22 Longitude:148.64 Depth(km):15Mechanism :OverthrustNodal plane 1, Strike:217 Dip:59 Slip: 58 Pole, Azimuth:127 Plunge:31Nodal plane 2, Strike:081 Dip:40 Slip: 132 Pole, Azimuth:351 Plunge:50T axis Azimuth:079 Plunge:64N axis Azimuth:232 Plunge:23 Uncertainty:~50°*12°P axis Azimuth:327 Plunge:11 Zoback Rating:D Fault Plane Rating:4Comments :The solution was originally compiled by Cleary et al.(1964) and revised by Denham etal.(1981). Despite using only eight stations with two compressions and six dilatations,the fit is reasonably good. The planedipping to the northwest, strike parallel to the tectonic trend, is reasonably well constrained, the other constrained only bythe orthogonality criterium. Cleary et al. favoured the northwest dipping nodal plane as the fault plane

Station Azimuth Plunge C +D -

CAN 19 22 -JIN 11 31 -RIV 39 42 +MEL 241 41 +CAB 149 21 -GEE 241 22 -WAW 262 33 -ADE 277 42 -

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Robertson 21st May 1961Date :1961 May 21Place :Robertson, southeast NSW between Sydney and Canberra. Wollongong 1:250000 MapSurface expression :Nil

Solution Reference :Denham(1980)Hypocentre source :Research School of Earth Sciences(RSES), ANU.Type of analysis :P wave polarity, Schmidt ProjectionMagnitudes :ML 5.6(RIV); mb 5.8Origin time (UTC) :214003Hypocentre, Latitude: -34.55 Longitude:150.50 Depth(km):19Mechanism :Vertical faultNodal plane 1, Strike:164 Dip:12 Slip: 123 Pole, Azimuth:074 Plunge:78Nodal plane 2, Strike:310 Dip:80 Slip: 83 Pole, Azimuth:220 Plunge:10T axis Azimuth:212 Plunge:55N axis Azimuth:312 Plunge:07 Uncertainty:~30°by18°P axis Azimuth:046 Plunge:34 Zoback Rating:E Fault Plane Rating:4Comments :The reference gives the solution as overthrust. However the uncertainty in the N axis,approximately 30° by 18°, allows also solutions with vertical and nodal planes, and normal fault solutions. The locations ofseven aftershocks in the first 24 hours identified the steeply dipping nodal plane as the fault plane, and that the strike of thefault is about 310° (or 130°). Both P and T axes plunge at about 45°, and on approximately reciprocal azimuths, giving aZoback stress rating of E.Possible interpretations include a vertical "gravity" fault in which the southwest side moves relativly downward and thenortheast side upward, a simple shear vertical movement not associated with a horizontal stress field.The fault is approximately orthogonal to the tectonic trend.

Station Azimuth Plunge C + D-

HLA 19 13 -RIV 37 14 -SAP 180 54 +SBA 176 61 +WER 187 7 +MOO 197 35 +FNT 196 34.5 +TRR 202 34.5 +MAW 206 64.5 +AYO 209 37 +WAM 219 33 +JIN 221 33 +GEE 226 33 +CBR 231 33 +MEL 233 34 +CAN 238 13 +ADE 265 33 +MUN 266.5 55 +LEM 296 60.5 +SHL 298 71 +DAR 317 55 +MAT 348 67 -JNL 330.5 3 +CTA 343 33 -

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Mt Hotham, 3rd May 1966Date :1966 May 03Place :Mt Hotham, central east Victoria. Bairnsdale 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1985)Hypocentre source :Denham et al.(1985)Type of analysis :P wave polarity, Schmidt ProjectionMagnitudes :ML 5.5; MS 3.8; mb 4.7Origin time (UTC) :190753.3Hypocentre, Latitude: -37.042 Longitude:147.158 Depth(km):15Mechanism :Normal faultNodal plane 1, Strike:309 Dip:43 Slip:-90 Pole, Azimuth:219 Plunge:47Nodal plane 2, Strike:129 Dip:40 Slip:-90 Pole, Azimuth:039 Plunge:50T axis Azimuth:039 Plunge:02N axis Azimuth:129 Plunge:00 Uncertainty:tight,non-orthogonalP axis Azimuth:219 Plunge:88 Zoback Rating:B Fault Plane Rating:2Comments :The solution is a normal fault tightly constrained, tight but non-orthogonal. To be orthogonal,nodal plane 2 should dip at 47° if nodal plane is held at a dip of 43°, or, both planes should dip at 45°.The T axis ishorizontal, trending northeast parallel to the tectonic trend, the fault strike being approximately orthogonal to the trend.Neither nodal plane is favoured as the fault plane.


BRS 23.5 44 -DLN 36 40.4 +JNL 36 43 +CAN 40 40.5 +CAB 43 41 +WAM 53 39 +BUV 120 18 -SAU 180 43 -TRR 187 45 -BOV 191 27.5 +MTV 198 40 -MEL 245 41 -TOO 248 41 -ADE 284 42 -WRA 326 48 -

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Meckering, 14th October Date :1968 October 14Place :Meckering,WA., Perth and Kellerberrin 1:250000 maps.Surface expression :Everingham(1968) reported that fracturing of the Earth's crust had occurred along an arc 32 kmlong, which trended roughly north-south with its convex side to the west. At the fracture zone a distinct scarp was formedby the movement of the eastern side upwards by up to 1.5 metres. A crustal shortening of up to 2 metres was also evident atthe fracture zone, and the east block moved south by up to 0.9 metres relative to the area west of the fracture. --- Theeffects at the surface are believed to be due to shallow thrust faulting with a right hand (dextral) strikeslip component. Thefault plane has an apparent east dip of about 35° judging by the ground displacements. --- Aftershocks occurred, mostwithin about 8 km of the trace of the fracture zone and to the east of it.

Solution Reference :Fredrich et al.(1988).Hypocentre source :ISCType of analysis :Moment tensor (Drawn on Schmidt Projection).Magnitudes :MS 6.8; Seismic moment 10.40±0.53*1018newton metreOrigin time (UTC) :025851.8Hypocentre, Latitude:-31.54 Longitude:117.00 Depth(km):1-5Mechanism :Nodal plane 1, Strike:351±10 Dip:29±7 Slip:73±10 Pole, Azimuth:261 Plunge:61Nodal plane 2, Strike:190 Dip:63 Slip:99 Pole, Azimuth:100 Plunge:27T axis Azimuth:122 Plunge:71N axis Azimuth:006 Plunge:09 Uncertainty:Moment tensorP axis Azimuth:273 Plunge:17 Zoback Rating:C Fault Plane Rating:3Comments :Fredrich et al. found the best fitting mechanism to be almost pure thrust faulting on a northstriking plane, with centroid depth 3 km. They took the east dipping plane to be the fault plane because of its agreementwith surface rupture. Their uncertainty in strike, dip and slip angles of ±10°, ±7°, and ±10° respectively, and differenceswith Vogfjord and Langston(1987) values of 7°, 1°, and 5° respectively, endorse the '3' Fault Plane Rating given toMoment Tensor Solutions.

Solution Reference :Fitch et al.(1973)Hypocentre source :Fitch et al.(1973)Type of analysis :P wave polarity plus S wave polarization and displacement spectral densities computed fromRayleigh waves, Schmidt Projection.Magnitudes :MS 6.8, seismic moment 6.1*1025 dyne cm.Origin time (UTC) :025851Hypocentre, Latitude:-31.68 Longitude:117.00 Depth(km):15Mechanism :Overthrust combined with sinistral strikeslip.Nodal plane 1, Strike:332 Dip:68 Slip: Pole, Azimuth: Plunge:Nodal plane 2, Strike:038 Dip:45 Slip: Pole, Azimuth: Plunge:T axis Azimuth:020 Plunge:50N axis Azimuth:169 Plunge:36 Uncertainty: Not ratedP axis Azimuth:271 Plunge:13 Zoback Rating:X Fault Plane Rating:X

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Comments :USCGS depth, 1 km. ISC depth, 18 km. This solution is not rated as it does not fit the surfacedata, a fact recognised in the reference. The earthquake is seen as a multiple rupture, starting about 3.5 seconds before themain shock, as a sinistral strike slip motion more or less consistent with the P wave data. But motion is envisaged to be onthe plane striking NNW, dipping WSW, with overthrust and strike slip motions opposite to the surface expressions. The Pwave data alone is inconsistent with the given overthrust solution on NNW strike, although additional information in theform of S wave polarisation data and displacement spectral density data computed from Rayleigh waves were used in theanalysis.

Solution Reference :The P wave data of Fitch et al.(1973), Figure 2, and page 350.Hypocentre source :Fitch et al.(1973).Type of analysis :P wave polarity, Schmidt Projection.

Magnitudes :MS 6.8Origin time (UTC) :025851Hypocentre, Latitude:-31.68 Longitude:117.00 Depth(km):5Mechanism :Dextral strikeslipNodal plane 1, Strike:019 Dip:82 Slip: Pole, Azimuth:289 Plunge:08Nodal plane 2, Strike:109 Dip:82 Slip: Pole, Azimuth:019 Plunge:08T axis Azimuth:335 Plunge:11N axis Azimuth:151 Plunge:79 Uncertainty:Anomalous stationsP axis Azimuth:63 Plunge:01 Zoback Rating:X Fault Plane Rating:XComments :Fitch et al.(1973) note that their P wave data, their Figure 2, are consistent with a strikeslipsolution for an initial event 3.5 seconds before the main shock. The solution given here using the P wave polarity data andthe position of the B (N) axis given on page 350, is a tight strikeslip solution, but dextral on a NNE trending plane ratherthan on the NNW trending plane. As Fitch et al. were not happy with the quality of some P wave data anyway, and as theyused additional information to get their overthrust solution, this strike slip solution is not rated. An additional strikeslipsolution has been drawn from the same data (Fitch et al., Figure 2). The solution is tight with a couple of anomalousstations. The motion would be dextral on the plane striking NNE. The parameters are given below.

Solution Reference :Vogfjord and Langston(1987)Hypocentre source :Vogfjord and Langston(1987)Type of analysis :Moment tensor (shown on Schmidt Projection).Magnitudes :MS 6.8, Seismic moment 8.2*1025 dyne cmOrigin time (UTC) :

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Hypocentre, Latitude: Longitude: Depth(km):3Mechanism :OverthrustNodal plane 1, Strike:341 Dip:37 Slip:61 Pole, Azimuth:251 Plunge:54Nodal plane 2, Strike:015 Dip:58 Slip:119 Pole, Azimuth:105 Plunge:31T axis Azimuth:148 Plunge:69.9N axis Azimuth:004.5 Plunge:16.7 Uncertainty:Moment tensorP axis Azimuth:271 Plunge:11.3 Zoback Rating:C Fault Plane Rating:3Comments :Vogfjord and Langston(1987) indicate a depth of 3 km for the earthquake, rupture initiating atdepth 1 km (1.5 km in Langston(1987)) and progressing radially (downward) to a depth of nearly 6 km. Their fault planedips eastward at a shallow angle in agreement with the surface rupture. Langston(1987) stated that considering the size ofthe Meckering earthquake and the 37-km-long fault scarp that it produced, it is evident that this area is currently uniqueamong the seismogenic regions of the Earth. The small foreshock 3.5 seconds before the main shock was not included inthe "inversion window".

Further comments :Gordon and Wellman(1971), with revisions to the diagram by Gordon and Lewis(1980, Figure74 page 162), offered a possible mechanism for the Meckering earthquake to produce a dextral fault component in asinistral shear zone. They considered that the zone of earthquakes which strikes northwest across southwest WesternAustralia, the South-western Australian Seismic Zone, involves sinistral shear. They envisaged a spherical cap sitting onthe shear zone and extending out beyond the shear zone on both sides, to the southwest and northeast. A slow buildup ofelastic strain occurs in the part of the upper cap within the shear zone. The section of cap outside the shear zone remainsunstrained. The cap then snaps free from the underlying rock to resume its unstrained state. Gordon and Wellman(1971)and Gordon and Lewis(1980) asserted that this rebound involves dextral faulting at the margin of the cap. However theirhypothesis appears to be in error in their very first stage, the straining of the cap before earthquake rebound. The figure(Figures 2 and 74 respectively), shows strain deformation (change of shape) in the sections of the cap outside the shearzone, as well as within, contrary to the statement "and the part outside is carried along bodily without being strained".

Denham et al.(1980) also discussed a possible earthquake trigger for the Meckering earthquake. They found the stress dropto be ~9Mpa. Measurements of maximum principal stress by shallow overcoring was highest, 23Mpa, at the site farthestnorth from the epicentre, and the lowest, 4Mpa, near the epicentre. As a cause of the earthquake, Denham et al. proposedthat the fault plane is progressively weakened by alteration or weathering, and that a small long term fluctuation of head ofgroundwater was the trigger.

13

Calingiri, 10th March 1970Date :1970 March 10Place :Calingiri, W.A., Perth 1:250000 Map.Surface expression :A north-south trending fault scarp was formed. Everingham and Parkes(1971) and Everinghamet al.(1982) reported that the earthquake caused an east-dipping thrust fault over a distance of about 5 km, where thesurface was uplifted by as much as 30 cm. (There was) shortening and misalignment of wire fences and a bump in a roadwhere the fault scarp crossed it.

Solution Reference :Fitch, et al.(1973).Hypocentre source :USCGSType of analysis :P wave polarity, Schmidt ProjectionMagnitudes :mb 5.7; ML 5.1(MUN)Origin time (UTC) :171508.5Hypocentre, Latitude:-31.01 Longitude:116.54 Depth(km):15(Fitch et al. model); 5(USCGS); 1 (BMR)Mechanism :Overthrust with strikeslipNodal plane 1, Strike:157 Dip:76 Slip: 39 Pole, Azimuth:67 Plunge:14Nodal plane 2, Strike:56 Dip:50 Slip: 163 Pole, Azimuth:326 Plunge:40T axis Azimuth:23 Plunge:39N axis Azimuth:172 Plunge:46 Uncertainty:~120°*100°P axis Azimuth:282 Plunge:16 Zoback Rating:E Fault Plane Rating:5Comments :The Calingiri earthquake was located about 80 km northwest of the Meckering earthquake.Fitch et al. note that the earthquake was only well recorded by short period instruments, that it provides additional insightinto complex fault movements in southwest Australia, (but) that the solution "is constrained to be similar to the Meckeringmain shock".The uncertainty is about 120°*100°. The overthrust can be oriented almost around the clock. As Fitch et al. constrained thesolution on the edge of the uncertainty pattern to be similar to the Meckering solution, the solution should not be used onstress azimuth maps.

14

Lake MacKay, 24th March 1970Date :1970 March 24Place :East Canning Basin / Lake Mackay. Helena and Wilson 1:250000 Maps, central/northwestAustralia, in Western Australia.Surface expression :Nil.

Solution Reference :Denham et al.(1974); Worotnicki and Denham(1976).Hypocentre source :AGSOType of analysis :P wave polarity, Wulff ProjectionMagnitudes :mb 6.2; MS 5.9; ML 6.7 (AGSO)Origin time (UTC) :102534Hypocentre, Latitude:-22.05 Longitude:126.61 Depth(km):8Mechanism :OverthrustNodal plane 1, Strike:136 Dip:70 Slip: Pole, Azimuth:046 Plunge:20Nodal plane 2, Strike:289 Dip:22 Slip: Pole, Azimuth:199 Plunge:68T axis Azimuth:058 Plunge:64N axis Azimuth:310 Plunge:08 Uncertainty:20°*15°P axis Azimuth:218 Plunge:14 Zoback Rating:C Fault Plane Rating:3Comments :The solution is a reasonably well constrained overthrust on a northwest-southeast strike,southwest pressure axis.Nodal plane 1 is held against the zone of P wave compressions by dilatations at stations MIR andMAW. (Station CLV recorded an emergent, not dilatational, arrival.) The other nodal plane is then constrained to passbetween ASP (compression) and WRA (dilatation). Either plane could be the fault plane.Denham et al. reported that the aftershock zone trends NNW-SSE.

Solution Reference :Fitch et al.(1973)

Hypocentre source :Fitch et al. (1973)Type of analysis :P wave polarity with S wave polarization; Schmidt ProjectionMagnitudes :MS 5.9Origin time (UTC) :103522Hypocentre, Latitude:-21.98 Longitude:126.68 Depth(km):15Mechanism :OverthrustNodal plane 1, Strike:340 Dip:40 Slip: Pole, Azimuth:250 Plunge:50Nodal plane 2, Strike:127 Dip:56 Slip: Pole, Azimuth:217 Plunge:34T axis Azimuth:344 Plunge:70N axis Azimuth:139 Plunge:20 Uncertainty:almost 360°.P axis Azimuth:232 Plunge:09 Zoback Rating:X Fault Plane Rating:XComments :Using just the P wave polarities, an overthrust solution on virtually any azimuth is possible.There are no dilatations. Australian station dilatations on which the Denham et al. solution relies are not used. Fitch et al.state that the solution is mainly controlled by S wave polarization ( to give the solution its northwest-southeast strike).

15

Solution Reference :Fredrich et al.(1988)Hypocentre source :ISCType of analysis :Moment tensor (drawn on Schmidt Projection)Magnitudes :MS 5.9Origin time (UTC) :103516.8Hypocentre, Latitude:-22.08 Longitude:126.65 Depth(km):8±3 (Fredrich et al.)Mechanism :OverthrustNodal plane 1, Strike:161±5 Dip:45±10 Slip:80±5 Pole, Azimuth:071 Plunge:45Nodal plane 2, Strike:356 Dip:48 Slip: Pole, Azimuth:266 Plunge:42T axis Azimuth:336 Plunge:82N axis Azimuth:169 Plunge:07 Uncertainty:Moment tensorP axis Azimuth:078 Plunge:01 Zoback Rating:C Fault Plane Rating:3Comments :The solution is almost pure thrust on a north striking plane. Author uncertainties are of order of5°-10°, equivalent to fault plane rating 3.The centroid depth of 8 km indicates an upper crustal, but not surface earthquake.

Further comments: Three fault plane solutions of the 24 March 1970 Canning Basin earthquake are listed here. Thefirst (Denham et al., 1974) used only P wave polarities of global and Australian seismic stations. The second (Fitch etal.,1973) supplemented P wave polarities with S wave polarization directions. The third (Fredrich et al.,1988) was amoment tensor solution. In the second solution, if only P wave polarities were used, the possible N axis azimuth could vary by virtually 360°, but ifS wave polarization was also considered, the position of the T axis could be constrained somewhat better.Comparing the first and third solutions, both are reasonably good with both having Zoback and Fault Plane ratings of C and3 respectively. Both solutions are overthrust. However, the N axis azimuths differ by 39°, and the N axis plunges by 15°. Inother words, there is a significant difference between the two reasonably good solutions, one P wave polarity and the othermoment tensor.The difference could be that the P wave polarity method examines the initial rupture configuration, while the momenttensor method looks at the whole event, and the two may have real fault plane orientation differences. If not, thediscrepancies between the two solutions highlights the uncertainties between the methods.


MAT 6 70 +KNA 18 13 -

16

DAR 23 25 -RAB 59 62 +RMG 60 55 +HNR 73 63 +WRA 75 25 -CTA 86 46 +AFI 95 69 +ASP 105 7 +COL 106 78.2 +BRS 109 58 +CAN 127 57 +WEL 129 63 +TOO 136 53 +HTT 142 38 +ADE 143.5 42 +TAO 150 60.3 +SPA 174 69 +SBA 178 72 +MIR 196 67 -MAW 199 69 -KLG 206 24 -MUN 220 30 -MEK 237 18.5 -BUL 244 76.4 +POO 300 72.5 +LEM 306 57 +LAH 310.5 74 +CHG 322 67 +HKC 348 62.3 +DAV 356 62 +

17

Middlingbank, 21st June 1971Date :1971 June, 21 and 22Place :Middlingbank,southeast NSW, Bega 1:250000 MapSurface expression :NilSolution Reference :Bock and Denham(1983) composed a twelve earthquake composite of earthquakes whichoccurred at latitude -36.22°, longitude 148.78°, near Middlingbank in the Snowy Mountains. Main shock magnitude wasML 4.0. The composite solution is essentially strikeslip on an east-west or north-south trending plane. The earthquakes arethought to have been triggered by the filling of Lake Eucumbene.

18

Dalton, 3rd November 1971Date :1971 November 03Place :Dalton, southeast NSW,Goulburn 1:250000 MapSurface expression :Nil

Solution Reference :Denham et al.(1981)Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 4.2Origin time (UTC) :200536.7Hypocentre, Latitude:-34.78 Longitude:149.17 Depth(km):3Mechanism :OverthrustNodal plane 1, Strike:312 Dip:50 Slip: 27 Pole, Azimuth:222 Plunge:40Nodal plane 2, Strike:204 Dip:70 Slip: 136 Pole, Azimuth:114 Plunge:20T axis Azimuth:161 Plunge:44N axis Azimuth:003 Plunge:32 Uncertainty:~25°*25°P axis Azimuth:262 Plunge:12 Zoback Rating:C Fault Plane Rating:4Comments :The aftershock pattern favours the plane striking northwest, dipping to the northeast, as the faultplane. The auxiliary plane is reasonably well restrained, but the fault plane is restrained only by the orthogonality criterium.

Station Azimuth Plunge C + D - JUL 38 24 -RIV 62 42 -AVO 73 23 -WAM 188 23 +CAN 194 11 +JIN 195 40 +CAH 205 6 +CAB 207 23.5 +KHA 213 31 +TAO 221 12 -TOO 228 42 -LER 311 5 -

19

Temora, 25th February 1972Date :1972 February 25Place :Temora, central-south NSW, Cootamundra 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1985).Hypocentre source :Denham et al.(1985).Type of analysis :P wave polarity, Schmidt projection. Magnitudes :ML 5.2Origin time (UTC) :152236Hypocentre, Latitude:-34.22 Longitude:147.47 Depth(km): 0 km.Mechanism :StrikeslipNodal plane 1, Strike:137 Dip:85 Slip: 0 Pole, Azimuth:047 Plunge:05Nodal plane 2, Strike:227 Dip:85 Slip: 180 Pole, Azimuth:137 Plunge:05T axis Azimuth:092 Plunge:07N axis Azimuth:274 Plunge:88 Uncertainty:~50°*15°P axis Azimuth:003 Plunge:01 Zoback Rating:D Fault Plane Rating:4Comments :Both nodal planes are virtually vertical and could dip steeply either way. The plane strikingnortheast-southwest is poorly constrained. Both P and T axes are virtually horizontal, pressure axis north-south, tensionaxis east-west. Based on this solution, the earthquake could have been pure shear caused by north-south compression, butjust as easily by east-west extension. It could also have been caused by a northwest-southeast dextral simple shear or anortheast-southwest sinistral simple shear.The tectonic strike is northeast-southwest.

Station Azimuth Plunge C + D - JNL 19 40 -RIV 84.5 41 +WER 86.5 38.5 +CAH 106 37 +INV 112 40 +LER 115 40 +CAN 131 40 +WAM 150 39 -TAD 154 32.5 -CBR 156 40 -JIR 159 39 -KHA 165 39 -TOO 204 41 -ADE 259 48 +ASP 306 43 -WRA 316 45 -

20

Simpson Desert, 28th August 1972Date :1972 August 28Place :Simpson Desert Northern Territory, central Australia, Hale River and McDills 1:250000 Maps.Surface expression :Nil

Solution Reference :Stewart and Denham(1974); Worotnicki and Denham(1976).Hypocentre source :Stewart and Denham(1974).Type of analysis :P wave polarity, Wulff projectionMagnitudes :mb 5.6 (ML 6.2 inferred from mb).Origin time (UTC) :021851.6Hypocentre, Latitude:-24.74 Longitude:136.92 Depth(km):7Mechanism :Strikeslip, slight overthrustNodal plane 1, Strike:53 Dip:64 Slip: 31 Pole, Azimuth:323 Plunge:26Nodal plane 2, Strike:308 Dip:63 Slip: 149 Pole, Azimuth:218 Plunge:27T axis Azimuth:271 Plunge:39N axis Azimuth:089 Plunge:51 Uncertainty:~24°*12°P axis Azimuth:181 Plunge:01 Zoback Rating:C Fault Plane Rating:3Comments :Based on the northeast-southwest trend of the aftershock sequence, Stewart and Denhamconsider the northeast striking nodal plane to be the fault plane. The P axis is virtually horizontal, while the T axis plungesat 39°, and a north-south horizontal compression is implied.Stewart and Denham suggest that it is clear that most of the seismic activity between 135 and 140°E can be explained by aregional stress field resulting from a predominantly N-S pressure axis. The seismic zones probably occur along old zones ofweakness - such as the edges of an old proto-continent or the edges of large basins.

Station Azimuth Plunge C +D-

1 84.3 +2 86 +3 87 +

RMG 34 58.5 -46 89 +

CAR 112 78.5 +UAV 118 86 +GNZ 124 67 -CNZ 127 69 -RIV 129 53 -MSZ 135 69 -CAN 139 52 -UMB 152 49 -TOO 153 52 -SAU 156 58 -TAO 160 62 -TRR 162 59 -HTT 171.3 50 -MIR 172 78 +PNA 174 49 -ADE 175 50 -SBA 177 73 +DRV 179 70 +SPA 180 74.5 +ILN 183 49 -SNA 196 76.5 +NLV 198 74.5 +OOD 207 48.5 -MAW 208 73 +KLG 244 51 +MUN 245 48 -

21

MEK 260 53 +KIO 260 53 +ASP 291 48 +GRF 294 84 +LEM 298 66 +HFS 312.5 84 -KNA 321 49 +MAT 359 73 +

22

Gunning, 8th January 1973Date :1973 January 8Place :Gunning, southeast NSW, Goulburn 1:250000Map.Surface expression :Nil

Solution Reference :Denham, et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 2.5 (RSES/ANU)Origin time (UTC) :224713.5Hypocentre, Latitude:-34.89 Longitude:149.34 Depth(km):2Mechanism :Strikeslip with some normal fault or a little overthrust movement, or mainly a normal fault withsome strikeslip.Nodal plane 1, Strike:119 Dip:70 Slip: -9 Pole, Azimuth:029 Plunge:20Nodal plane 2, Strike:212 Dip:82 Slip: -159 Pole, Azimuth:122 Plunge:08T axis Azimuth:345 Plunge:05N axis Azimuth:238 Plunge:68 Uncertainty:~ 60°*1°.P axis Azimuth:077 Plunge:24 Zoback Rating:D Fault Plane Rating:5Comments :The strike of both nodal planes are well constrained, the first (southeast striking) by theorthogonality criterium. As the earthquake is so small, there are no distant stations in the centre of the Schmidt projection toconstrain the Null axis.The plane striking southeast is favoured as the fault plane as it follows the general strike of the Dalton-Gunning fault zone.The earthquake is given as evidence for compressive stress in the southeast Australian crust, but the solution also favours atensional stress, perhaps even more so. If the mechanism is simple shear, as with two blocks moving past each other, thenthe earthquake is not evidence for a regional compressive stress.

Station Azimuth Plunge C + D - JNL 29.3 29 -WEK 50 29 -AVO 65 21 -IVN 106 5 -WAM 196.7 30 +CAN 214 14 +CBR 217 28 -KHA 216 37 +TAO 232 20 -YOU 308 20 +BWA 314 20 +LER 323 15 -CAH 343 16 +

23

Picton, 9th March 1973Date :1973 March 09Place :Picton, Sydney Basin, east NSW, Wollongong 1:250000 Map.Surface expression :Nil

Solution Reference :Fitch(1973), Mills and Fitch(1977).Hypocentre source :RSES/ANUType of analysis :P wave polarity, Schmidt projection; Rayleigh/Love wave excitation.Magnitudes :mb 5.5; MS 5.3; ML 5.5Origin time (UTC) :190914.7Hypocentre, Latitude:-34.17 Longitude:150.32 Depth(km):21Mechanism :OverthrustNodal plane 1, Strike:355 Dip:54 Slip: 120 Pole, Azimuth:265 Plunge:36Nodal plane 2, Strike:130 Dip:46 Slip: 55 Pole, Azimuth:040 Plunge:44T axis Azimuth:323 Plunge:65N axis Azimuth:156 Plunge:25 Uncertainty:11°*1°.P axis Azimuth:064 Plunge:06 Zoback Rating:B Fault Plane Rating:2Comments :The plane dipping east is tightly constrained by a dilatation on the wrong side of the nodalplane. The other nodal plane is then reasonably well constrained by the orthogonality criterium. Aftershock locationsfavour the east dipping plane as the fault plane, depth range 8-24km with a lateral extent of about 8km (Mills andFitch,1977). Fitch(1973) notes that the strike of this plane is nearly parallel to the western margin of the Sydney Basin.The dotted overthrust solution on the Mills and Fitch(1977) diagram is a solution based on surface wave amplitudes.However it is intended only to show favour to the P wave polarity overthrust solutions (solid curves) over an alternativenorthsouth/eastwest strikeslip solution which is reasonably tight with anomalous stations close to the nodal planes.

Solution Reference :AlternativeType of analysis :P wave polarities from Mills and Fitch(1977), Schmidt projection.Mechanism :StrikeslipNodal plane 1, Strike:358 Dip:80 Slip: Pole, Azimuth:268 Plunge:10Nodal plane 2, Strike:090 Dip:82 Slip: Pole, Azimuth:000 Plunge:08T axis Azimuth:315 Plunge:10N axis Azimuth:116 Plunge:78 Uncertainty:Tight,anomalous stationsP axis Azimuth:223 Plunge:05

Station Azimuth Plunge C + D - 17 41 +64 43 -101 45 +115 55 -131 47 +132 72 +133 46 +166 50 +177 64 -197 41 -200 41 -

24

213 39 -213 38.5 -223 39 -225 40 -229 40 -230 39 -242 38 -264 61 +276 61 +294 65 +294 75 +302 49 +308 72 +310 55 +316 62 +332 39 +344 46 +352 59 +

25

Gunning, 22 March 1974Date :1974 March 22Place :Dalton Gunning, southeast NSW, Goulburn 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, with aftershock pattern.Magnitudes :ML 3.0Origin time (UTC) :173749Hypocentre, Latitude:-34.75 Longitude:149.19 Depth(km):4Mechanism :IndeterminateNodal plane 1, Strike:073 Dip:58 Slip:150 Pole, Azimuth:343 Plunge:32Nodal plane 2, Strike:180 Dip:65 Slip:36 Pole, Azimuth:090 Plunge:25T axis Azimuth:040 Plunge:42N axis Azimuth:210 Plunge:48 Uncertainty:~100°*60°.P axis Azimuth:320 Plunge:05 Zoback Rating:X Fault Plane Rating:XComments :As noted by Denham et al., the focal mechanism is very poorly determined, but an aftershockzone exists which trends approximately ENE-WSW through the epicentre. The solution with one station anomalous (LER,compresssion) can vary through overthrust, strikeslip and normal fault, with the aftershock pattern favouring overthrust.However, the solution could hardly be considered reliable and should not be used in Australia stress map diagrams.

Station Azimuth Plunge C + D - WER 55 24 +WAM 190 25 -CAN 195 13 +CAH 203 17 +CBR 210 24 +KHA 211 24 +BWA 311 13 -LER 320 5 +

26

Murrumbateman, 6th May 1974Date :1974 May 06Place :South of Dalton-Gunning-Yass, southeast NSW, Canberra 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 3.8Origin time (UTC) :194620.7Hypocentre, Latitude:-35.03 Longitude:149.02 Depth(km):5Mechanism :Strikeslip/overthrust.Nodal plane 1, Strike:322 Dip:55 Slip:25 Pole, Azimuth:232 Plunge:35Nodal plane 2, Strike:217 Dip:70 Slip:142 Pole, Azimuth:127 Plunge:20T axis Azimuth:174 Plunge:39N axis Azimuth:013 Plunge:49 Uncertainty:~34°*24°.P axis Azimuth:271 Plunge:10 Zoback Rating:D Fault Plane Rating:4Comments :The solution is reasonably good except for the anomalous station LER compression. (StationLER polarity was also anomalous in the 22 March 1974 solution.) It is a combination of strikeslip and overthrust with ahorizontal east-west pressure axis.

Station Azimuth Plunge C + D - CAN 3 6 +JNL 37 25 -WER 52 34 -RIV 58 43 -AVO 64 26 -IVN 84 13 -WAM 184 22 +CBR 208 11 +KHA 212 23 +TOO 228 42 +BFD 247 42 -LEP 250 5 +YOU 325 14 -BWA 339 14 +

27

Gunning, 4th August 1975Date :1975 August 04Place :Dalton-Gunning, southeast NSW, Goulburn 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 3.1Origin time (UTC) :171703Hypocentre, Latitude:-34.78 Longitude:149.19 Depth(km):1Mechanism :Overthrust or normal fault or strikeslip/overthrust.Nodal plane 1, Strike:074 Dip:60 Slip:90 Pole, Azimuth:344 Plunge:30Nodal plane 2, Strike:254 Dip:30 Slip:90 Pole, Azimuth:164 Plunge:60T axis Azimuth:344 Plunge:75N axis Azimuth:074 Plunge:00 Uncertainty:70°*60°.P axis Azimuth:164 Plunge:15 Zoback Rating:X Fault Plane Rating:XComments :The solution is poorly constrained. In addition to the overthrust solution, a normal fault solutionis possible, with virtually horizontal northeast trending T axis and steeply plunging P axis. The solution should not be usedin Australia stress map diagrams.

Station Azimuth Plunge C + D - WER 56 30 +AVO 72 29 +IVN 117 15 -LER 135 15 -WAM 191 29 -CAN 198 15 -CAH 196 4 -KHA 213 25 -CBR 211 29 -TAO 224 20 -BWA 313 15 -

28

The Pilot, 8th September 1976Date :1976 September 08Place :Pilot Mountain, Snowy Mtns, southeast NSW, Tallangatta 1:250000.Surface expression :Nil

Solution Reference :Bock and Denham(1983).Hypocentre source :Bock and Denham(19830Type of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 3.8Origin time (UTC) :042135.9Hypocentre, Latitude:-36.72 Longitude:148.24 Depth(km):6Mechanism :OverthrustNodal plane 1, Strike:224 Dip:60 Slip:68 Pole, Azimuth:134 Plunge:30Nodal plane 2, Strike:078 Dip:36 Slip:119 Pole, Azimuth:348 Plunge:54T axis Azimuth:100 Plunge:67N axis Azimuth:234 Plunge:17 Uncertainty:~60°*1°P axis Azimuth:326 Plunge:08 Zoback Rating:D Fault Plane Rating:5Comments :While one nodal plane is tightly constrained, the other is hardly constrained at all. Despite somevariation in azimuth, the P axis remains close to horizontal.


YOU 2 44 -TAO 2.2 16 -CBR 10 16 -BWA 11 44 -CAH 22.3 45 +CAN 26 25 -LER 28 44 +IVN 34 44 -TOO 249 43 +BFD 264 43 -DRT 283 15 -STK 311 43 -KHA 351 15 -

29

Dalton, 5th April 1977Date :1977 April 05Place :Dalton, southeast NSW, Goulburn 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :Denham et al.(1981).From RSES/ANU, but depth 0 km, not 15 km.Type of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 3.2.Origin time (UTC) :103121.1Hypocentre, Latitude:-34.74 Longitude:149.18 Depth(km):0Mechanism :Strikeslip with either overthrust or normal fault.Nodal plane 1, Strike:187 Dip:70 Slip: -3 Pole, Azimuth:097 Plunge:20Nodal plane 2, Strike:098 Dip:90 Slip: -180 Pole, Azimuth:008 Plunge:00T axis Azimuth:052 Plunge:14N axis Azimuth:278 Plunge:70 Uncertainty:~80°*1°.P axis Azimuth:144 Plunge:14 Zoback Rating:D Fault Plane Rating:5Comments :The north-south striking nodal plane is well constrained in the sense that one station polarity(CBR, dilatation) is close to the nodal plane but anomalous. There is little control on the other nodal plane which can makethe solution strikeslip/overthrust or strikeslip/normal. Both P and T axes remain approximarely horizontal, southeast andnortheast respectively.


JNL 37 20 +WER 56 29 +IVN 121 16 -SBR 160 21 -KOW 171 19 -WAM 191 30 -CAN 196 16 +CAH 203 2 +CBR 210 29 -KHA 214 36 +TAO 223 19 +YOU 306 19 -BWH 312 14 -LER 319 0 -

30

Quorn, 16th April 1977Date :1977 April 16Place :Quorn, South Australia, Port Augusta 1:250000 map.Surface expression :Nil

Solution Reference :McCue and Sutton(1979)Hypocentre source :McCue and Sutton(1979). Type of analysis :P wave polarities, Wulff projection; aftershock locations.Magnitudes :ML 3.8Origin time (UTC) :181920Hypocentre, Latitude:-32.44 Longitude:137.96 Depth(km):5Mechanism :Strikeslip or normal fault.Nodal plane 1, Strike:026 Dip:90 Slip:-180 Pole, Azimuth:296 Plunge:00Nodal plane 2, Strike:297 Dip:68 Slip:3 Pole, Azimuth:207 Plunge:22T axis Azimuth:159 Plunge:17N axis Azimuth:026 Plunge:68 Uncertainty:~60°*45°.P axis Azimuth:254 Plunge:17 Zoback Rating:E Fault Plane Rating:5Comments :The solution is poorly constrained. As a number of aftershocks were clustered about a set ofnortherly trending faults( McCue and Sutton) the fault plane is constrained to lie as northerly as possible. Without thisconstraint, a normal fault solution with ENE trend may be possible, depending on polarity amplitudes of critical stations.Re-evaluation of seismograms would be necessary to check these, but is not feasible at this time.

Station Azimuth Plunge C + D - UMB 25 51 +LGP 68 17 -HTT 133 49 +ADE 168 49 +END 196 28 +CIV 225 49 -STK 261 4 -HKN 313 50 -COO 301 13 +WSA 321 50 +SCK 333 18.5 +NCK 350 17 +NBK 355 22 +

31

Bowning, 30th June 1977Date :1977 June 30Place :Bowning, southeast NSW. Goulburn 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, aftershock pattern.Magnitudes :ML 4.2 (a foreshock to a ML 4.8 earthquake).Origin time (UTC) :124822.3Hypocentre, Latitude:-34.67 Longitude:148.87 Depth(km):12Mechanism :Motion on a vertical fault.Nodal plane 1, Strike:210 Dip:88 Slip: 27 Pole, Azimuth:120 Plunge:02Nodal plane 2, Strike:119 Dip:50 Slip:178 Pole, Azimuth:029 Plunge:40T axis Azimuth:082 Plunge:29N axis Azimuth:212 Plunge:50 Uncertainty:Tight with anomalous polaritiesP axis Azimuth:337 Plunge:25 Zoback Rating:D Fault Plane Rating:4Comments :An orthogonal solution is not possible as two station polarities are anomalous but close to anodal plane. Similar solutions can be drawn, depending on which anomalous station polarities are subjectively ignored. Thesolution on its own should not be interpreted as indicating a compressional tectonic stress field, as a tensional stress fieldand even simple shear are also possible interpretations.Parameters for a similar alternative solution are shown below.The earthquake is a foreshock to a magnitude ML 4.8 earthquake which occurred four days later about 10 km to the NNE.The aftershock zone of these two earthquakes trends NNE (Everingham and Smith, 1979), so that the vertical nodal planetrending NNE is the likely fault plane.

Solution Reference :AlternativeType of analysis :P wave polarities of Denham et al.(1981), Schmidt projection.Mechanism :Motion on a vertical fault.Nodal plane 1, Strike:034 Dip:84 Slip: Pole, Azimuth:304 Plunge:06Nodal plane 2, Strike:132 Dip:36 Slip: Pole, Azimuth:042 Plunge:54T axis Azimuth:093 Plunge:32N axis Azimuth:210 Plunge:34 Uncertainty:Tight with anomalous polarities.P axis Azimuth:336 Plunge:41

Station Azimuth Plunge C + D - JNL 51 20 +WER 64 28 +RIV 70 35 +AVO 79 28.5 +YOU 134 5 +PNH 140 32 +SBR 142 20 -BWA 158 17 +WAM 179.5 29 -CBR 196 21 -

32

KHA 199 34 -TAO 206 22 -DRT 208 36 -TOM 213 36 +TOO 224 36 +BFD 244 34 +CAH 266 16 +STK 293 36 -INV 294.5 6 -LER 302 10 -KOW 330 7 -CAN 351 7 -

33

Bowning, 4th July 1977Date :1977 July 04Place :Bowning, southeast NSW. Goulburn 1:250000 Map.Surface expression :Nil

Solution Reference :Everingham and Smith(1979); Denham et al.(1981).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, aftershock pattern.Magnitudes :mb 4.2; ML 4.8Origin time (UTC) :200520.6Hypocentre, Latitude:-34.65 Longitude:148.89 Depth(km):13Mechanism :Strikeslip/overthrustNodal plane 1, Strike:205 Dip:64 Slip:28 Pole, Azimuth:115 Plunge:26Nodal plane 2, Strike:102 Dip:64 Slip: 152 Pole, Azimuth:012 Plunge:26T axis Azimuth:064 Plunge:38N axis Azimuth:242 Plunge:51 Uncertainty:~10°*1°.P axis Azimuth:154 Plunge:00 Zoback Rating:B Fault Plane Rating:2Comments :The solution was first presented by Everingham and Smith(1979) and revised by Denham etal.(1981) with the inclusion of more stations. Apart from one anomalous station polarity, the solution is reasonably wellconstrained. The NNE trending aftershock pattern favours the NNE-SSW striking nodal plane as the fault plane. The P axisis horizontal, and Denham et al. suggest that the earthquake was caused by compressive forces acting approximately NW-SE.


BRS 26 34 +COO 34 36 +JNL 50 20 +WER 63 28 +RIV 68 33 +INV 117 20 -PNH 135 32 -YOU 132 8 -SBR 145 21 -KOW 151 22 -BWA 156 23 -CAN 172 22 -WAM 180 29 -CBR 196 29 -KHA 203 35 -TAO 207 21 -DRT 210 35 -TOM 215 35 -TOO 222 37.5 +LIL 224 32 -KGD 225 37 -MEL 227 34 +BFD 244 34 +STK 263 34 -CAH 268 18 +ADE 269 34 -CLV 276 34 -HTT 279 32 +GLS 298 48 -UMB 298 38 -ASPO 312 40 -LER 306 12 -WR3 320 46 -

34

Blinman, 30th August 1977Date :1977 August 30Place :Blinman, South Australia; Parachilna 1:250000 Map.Surface expression :Nil

Solution Reference :McCue and Sutton(1979).Hypocentre source :McCue and Sutton(1979).Type of analysis :P wave polarity, Wulff projection; local fault pattern.Magnitudes :ML 4.2; (ML 3.8, University of Adelaide).Origin time (UTC) :141347Hypocentre, Latitude:-31.06 Longitude:138.47 Depth(km):10Mechanism :StrikeslipNodal plane 1, Strike:176 Dip:90 Slip:0 Pole, Azimuth:266 Plunge:00Nodal plane 2, Strike:266 Dip:90 Slip:180 Pole, Azimuth:356 Plunge:00T axis Azimuth:311 Plunge:00N axis Azimuth:000 Plunge:90 Uncertainty:~20°*2°.P axis Azimuth:041 Plunge:00 Zoback Rating:C Fault Plane Rating:3Comments :The solution is fairly well constrained with north-south and east-west trending nodal planes.McCue and Sutton suggest that the north-south trending plane is probably the fault plane as the earthquake is close to anortherly trending fault on the western side of the Flinders Ranges. The motion would then be dextral. In addition to anortheast compressional stress field the earthquake could also have been caused by northwest tension or simple shear.

Station Azimuth Plunge C + D - PNA 15.9 13 -WSA 86 9 -STK 109 51 +TOO 141 51 +BFD 153 51 +HTT 172 51 +ADE 178 51 -CLV 214 51 -UMB 217 12 -HKN 289 49 +HTT 351 8.5 +ADE 358.5 8 -

35

Melton, 28th September 1977Date :1977 September 28Place :Melton, South Australia; Orroroo 1:250000 Map.Surface expression :Nil

Solution Reference :McCue and Sutton(1979).Hypocentre source :McCue and Sutton(1979).Type of analysis :P wave polarity; Wulff projection.Magnitudes :ML 4.0; (ML 3.6, University of Adelaide).Origin time (UTC) :191855Hypocentre, Latitude:-32.30 Longitude:139.31 Depth(km):15.Mechanism :Nodal plane 1, Strike:197 Dip:74 Slip: -159 Pole, Azimuth:107 Plunge:16Nodal plane 2, Strike:101 Dip:72 Slip:-19 Pole, Azimuth:011 Plunge:18T axis Azimuth:329 Plunge:02N axis Azimuth:237 Plunge:65 Uncertainty:~40°*15°.P axis Azimuth:060 Plunge:25 Zoback Rating:D Fault Plane Rating:4Comments :The solution is strikeslip although not particularly well constrained. Either station JNL or CANis anomalous, and McCue and Sutton preferred to use CAN in the solution. Giving preference to JNL would not have mucheffect.The T axis is horizontal; the P axis plunges slightly.

Station Azimuth Plunge C + D - CLV 61 5 -STK 79 49.5 -JNL 104 48.5 +CAN 113.5 49 -KHA 125 48.5 +DRT 134 48 +PNH 139 48 +BFD 152 48.5 +ADE 186 48.5 +HTT 192 50 +RRA 255 50 -PNA 286 48.5 +WSA 298 50 +HKN 302 50 +ASP 328 50 +UMB 353 51 +

36

Balling, 2nd December 1977Date :1977 December 02Place :Balling, Victoria. Melbourne 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1981).Hypocentre source :Denham et al.(1981).Type of analysis :P wave polarities, Schmidt projection, aftershock pattern.Magnitudes :ML 4.2; (ML 4.7, SRC).Origin time (UTC) :133233.2Hypocentre, Latitude:-37.88 Longitude:144.27 Depth(km):21Mechanism :Overthrust.Nodal plane 1, Strike:022 Dip:70 Slip:90 Pole, Azimuth:292 Plunge:80Nodal plane 2, Strike:202 Dip:70 Slip:90 Pole, Azimuth:112 Plunge:20T axis Azimuth:112 Plunge:65N axis Azimuth:022 Plunge:00 Uncertainty:~60°*60°P axis Azimuth:292 Plunge:25 Zoback Rating:X Fault Plane Rating:XComments :Two types of solution are possible. The Denham et al. solution is poorly constrained. It is anoverthrust with strike varying from north to northeast. A vertical nodal plane with the other plane dipping at about 30° ispossible. The P axis trends approximately WNW. The aftershocks (Denham et al., figure 4) appear to be scattered, butwould favour a fault plane dipping at a shallow angle to the ESE.An alternative solution, parameters shown below, is a normal fault with strikeslip. The T axis is horizontal and orientedSSW.

Solution Reference :AlternativeType of analysis :P wave polarities from Denham et al.(1981), Schmidt projection.Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:074 Dip:54 Slip: Pole, Azimuth:344 Plunge:36Nodal plane 2, Strike:328 Dip:68 Slip: Pole, Azimuth:238 Plunge:22T axis Azimuth:022 Plunge:08N axis Azimuth:122 Plunge:46 Uncertainty:~35°*15°.P axis Azimuth:286 Plunge:42

Station Azimuth Plunge C + D - YOU 43 34 +BWA 46 34.5 +AVO 55 32 +CAH 51 33.5 +IVN 54 36 +SBR 60 33 +DRT 64 32 +WAM 68 32 +THM 89 34 +PNH 110 9 -SAV 150 32.5 +MOO 152 34 +

37

TAU 153 34 +SFF 154 32 +SPK 163 34 +SVR 168 33 +GVL 244 26 -TOO 252 6 -KGD 256.5 12 -LYL 259 9 -BFD 296 33 -MEK 297 54 -ADE 303 34 -RPA 310 34 -HTT 316 33 -WSA 316 37 -PNA 320 33 -ASP 327 37 -UMB 331 33 -STK 340 34 -

38

Carrieton, 26 March 1978Date :1978 March 26Place :Carrieton, southeast South Australia; Orroroo 1:250000 Map.Surface expression :Nil

Solution Reference :Greenhalgh et al.(1994).Hypocentre source :Greenhalgh et al.(1994).Type of analysis :P wave polarity; Schmidt projection.Magnitudes :Ml 4.1Origin time (UTC) :223652Hypocentre, Latitude:-32.39 Longitude:138.92 Depth(km):16Mechanism :OverthrustNodal plane 1, Strike:260 Dip:66 Slip:79 Pole, Azimuth:178 Plunge:30Nodal plane 2, Strike:106 Dip:31 Slip:113 Pole, Azimuth:016 Plunge:59T axis Azimuth:155 Plunge:73N axis Azimuth:274 Plunge:08 Uncertainty: Anomalous stationsP axis Azimuth:005 Plunge:14 Zoback Rating:D Fault Plane Rating:5Comments :Different solutions can be drawn depending on which anomalous stations are ignored.Geeenhalgh et al. discarded station UMB, but they might have equally ignored station RPA to obtain a similar overthrustsolution rotated anticlockwise to a WSW-ENE strike. The P axis of the solution is approximately horizontal, orientednorth-south.The alternative solution with RPA anomalous is shown.

Solution Reference :AlternativeType of analysis :P wave polarities of Greenhalgh et al.(1984).Mechanism :Overthrust.Nodal plane 1, Strike:238 Dip:46 Slip: Pole, Azimuth:148 Plunge:44Nodal plane 2, Strike:094 Dip:50 Slip: Pole, Azimuth:004 Plunge:40T axis Azimuth:073 Plunge:70N axis Azimuth:257 Plunge:20 Uncertainty:~14°*1°.P axis Azimuth:169 Plunge:02

Station Azimuth Plunge C + D - HTT 1 9 -UMB 5 41 +RPA 75 4 -STK 78 41 +ELO 95 9.5 +CLV 237 43 +GLS 298 44 +WSA 303 43 -HKN 298 42 -ASP 333 43 -

39

Halls Creek, 6th May 1978Date :1978 May 06Place :Halls Creek, northern Western Australia; Mt Bannermann 1:250000 Map.Surface expression :Nil

Solution Reference :Everingham and Smith(1979).Hypocentre source :AGSOType of analysis :P wave polarity; Schmidt projection.Magnitudes :ML 6.2; mb 5.2(MUN)Origin time (UTC) :195219.6Hypocentre, Latitude:-19.55 Longitude:126.56 Depth(km):17Mechanism :Overthrust with some strikeslip.Nodal plane 1, Strike:020 Dip:50 Slip:37 Pole, Azimuth:290 Plunge:40Nodal plane 2, Strike:264 Dip:62 Slip:134 Pole, Azimuth:174 Plunge:28T axis Azimuth:228 Plunge:53N axis Azimuth:059 Plunge:37 Uncertainty:40°*1°, but two solutions possible.P axis Azimuth:325 Plunge:04 Zoback Rating:X Fault Plane Rating:XComments :In the listed solution, one nodal plane is well defined, but the other not so. The P axis ishorizontal and oriented approximately northwest. However a second solution is possible with N axis within the cluster ofstations in the southeast section of the projection. This solution is fairly well constrained, with a northerly P axis. Theparameters of the alternative solution are shown below.

Solution Reference :AlternativeType of analysis :P wave polarities of Everingham and Smith(1979), Schmidt prijection.Mechanism :Overthrust.Nodal plane 1, Strike:312 Dip:70 Slip: Pole, Azimuth:222 Plunge:20Nodal plane 2, Strike:060 Dip:48 Slip: Pole, Azimuth:330 Plunge:42T axis Azimuth:268 Plunge:45N axis Azimuth:112 Plunge:42 Uncertainty:12°*1°.

P axis Azimuth:010 Plunge:12Station Azimuth Plunge C + D - KNA 30 33 -CTA 96 47 -WB2 96 36 -BRS 115 54 +ASP 124 34 -UMB 136.2 39 -STK 137 45 -YOU 130 52 -PNA 144 40 -CLV 151 40 -KLG 204 35 +NWA 212 37 +SWV 218 38 +MEK 228 33 +MBL 256 31 +

40

KUP 342 33 + Simpson Desert, 25th November 1978Date :1978 November 25Place :southeast Northern Territory; Simpson Desert South 1:250000 map.Surface expression :Nil

Solution Reference :Everingham and Smith(1979). Hypocentre source :Everingham and Smith(1979).Type of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 4.7Origin time (UTC) :132141.7Hypocentre, Latitude:-25.88 Longitude:137.46 Depth(km):15(assumed).Mechanism :Overthrust solution.Nodal plane 1, Strike:029 Dip:45 Slip: Pole, Azimuth:299 Plunge:45Nodal plane 2, Strike:209 Dip:45 Slip: Pole, Azimuth:119 Plunge:45T axis Azimuth:000 Plunge:90N axis Azimuth:029 Plunge:00 Uncertainty:~30°*1°.P axis Azimuth:119 Plunge:00 Zoback Rating:X Fault Plane Rating:XComments :Everingham and Smith found that two solutions were possible,if station STK is ignored, beinganomalous to both solutions. One is a tight overthrust on a NNE-SSW strike. The other is strikeslip but with a large N axisuncertainty of ~60°*20°. In both solutions however, the P axis is approximately horizontal and oriented approximatelynorthwest-southeast, but this does not automatically imply a causative compressive stress.

Solution Reference :Everingham and Smith(1979), strikeslip solution.Type of analysis :P wave polarity, Schmidt projection.Mechanism :Strikeslip.Nodal plane 1, Strike:081 Dip:85 Slip: Pole, Azimuth:172 Plunge:00Nodal plane 2, Strike:172 Dip:80 Slip: Pole, Azimuth:082 Plunge:10T axis Azimuth:036 Plunge:08N axis Azimuth:262 Plunge:10 Uncertainty:~60°*10°.P axis Azimuth:127 Plunge:08

Station Azimuth Plunge C + D - CTA 55 32.5 +STK 151 28.5 +BFD 158.5 34 -UMB 160.3 28 -HTT 170 30 -ELO 173 28 -ADE 171.5 32 -PNA 172.5 30 -RPA 180 30 +WSA 186 28 +CLV 186 31 +WBN 267 33 -ASP 302 26 -

41

WCB 334 28 -

42

Broome, 23rd April 1979Date :1979 April 23Place :Continental shelf edge, northwest Australia.Surface expression :Nil

Solution Reference :Harvard University Seismology GrougType of analysis :Centroid Moment Tensor

Zoback Rating:C Fault Plane Rating:3042379B NORTHWEST OF AUSTRALIA Date (y/m/d): 1979/4/23Information on data used in inversion Wave nsta nrec cutoffBody 11 30 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsMLI 5 45 10.10 -16.54 120.18 33.0 5.9 5.7CMT 5 45 11.20 -16.62 120.16 34.0Error 0.20 0.02 0.03 -1.0Assumed half duration: 4.2Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 0.430 1.700 -2.130 -0.560 -0.280 -0.080Error 0.020 0.030 0.040 0.040 0.050 0.020Mw = 6.1 Scalar Moment = 2.04e+25Fault plane: strike=318 dip=71 slip=10Fault plane: strike=224 dip=80 slip=160Eigenvector: eigenvalue: 1.92 plunge: 21 azimuth: 180(T)Eigenvector: eigenvalue: 0.25 plunge: 68 azimuth: 19(N)Eigenvector: eigenvalue: -2.17 plunge: 7 azimuth: 272(P)Comments :The strikeslip CMT has north-south T axis and east-west P axis.\

43

Cadoux, 2nd June 1979Date :1979 June 02Place :Cadoux, southwest Western Australia; Bencubbin 1:250000 Map.Surface expression :Complex set of new surface faults within a north-south zone 15 km long and 3 km wide. Mainmovement in central part of zone was west over east, maximum throw about 1.3m with a dextral strike slip component(Denham et al.(1987). More detail is provided in Denham et al.(1987) and in Lewis et al.(1981).

Solution Reference :Denham et al.(1987).Hypocentre source :Denham et al.(1987).Type of analysis :Long period P and SH wave inversion, and P wave polarities, Schmidt projectionMagnitudes :ML 6.2; mb 5.9; MS 6.0.Origin time (UTC) :094758.7Hypocentre, Latitude:-30.83 Longitude:117.18 Depth(km):6Mechanism :OverthrustNodal plane 1, Strike:165 Dip:26 Slip:71 Pole, Azimuth:075 Plunge:64Nodal plane 2, Strike:007 Dip:64 Slip:100 Pole, Azimuth:277 Plunge:26T axis Azimuth:299 Plunge:68N axis Azimuth:182 Plunge:09 Uncertainty:Inversion.P axis Azimuth:090 Plunge:18 Zoback Rating:C Fault Plane Rating:3Comments :The nodal plane data was not provided, but was measured off the projection. The nodal planestriking north-south and dipping to the west would be favoured as the fault plane to agree with mid-fault surface overthrustdisplacement, west side over east.

Solution Reference :Harvard University Seismology GroupType of analysis :Centroid Moment Tensor

Zoback Rating:C Fault Plane Rating:060279A WESTERN AUSTRALIA** Date (y/m/d): 1979/6/2Information on data used in inversion Wave nsta nrec cutoffBody 10 26 45Mantle 4 7 135Timing and location information hr min sec lat lon depth mb MsMLI 9 47 58.10 -30.81 117.18 6.0 6.0 6.1CMT 9 48 5.00 -30.86 116.99 15.0Error 0.30 0.03 0.03 -1.0Assumed half duration: 4.2Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 1.280 0.380 -1.660 -0.810 0.090 0.250Error 0.030 0.030 0.040 0.080 0.110 0.030Mw = 6.1 Scalar Moment = 1.73e+25Fault plane: strike=200 dip=49 slip=132Fault plane: strike=326 dip=56 slip=52Eigenvector: eigenvalue: 1.75 plunge: 59 azimuth: 178(T)

44

Eigenvector: eigenvalue: -0.05 plunge: 30 azimuth: 349(N)Eigenvector: eigenvalue: -1.70 plunge: 4 azimuth: 82(P)Comments :Although the Harvard CMT solution is an overthrust similar to the inversion solution ofDenham et al., it is noted that the positions of the respective N axes differ by about 40°.

Station Azimuth Plunge C + D - 0 83 +4 51 +6 53 +13 59 +14 30 +14 43 +14 39 -18 25 +28 83 +38 59 +54 62 -58 55 +60 64 -70 83 +70 54 -71 38 -90 42 -90 60 -84 28 -97 57 -101 46 -108 52 -110 40 -113 58 +116 48 -121 64 -127 54 -177 26 +204 66 +215 29 +292 71 +328 58 +330 59 +335 59 +338 53 +338 65 +351 50 +

45

Broome, 14th July 1979Date :1979 July 14Place :Northwest Western Australia; Broome 1:250000 MapSurface expression :Nil


Zoback Rating:C Fault Plane Rating:3071479A WESTERN AUSTRALIA Date (y/m/d): 1979/7/14Information on data used in inversion Wave nsta nrec cutoffBody 9 19 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsMLI 9 40 50.70 -18.13 122.47 10.0 5.3 0.0CMT 9 40 51.60 -17.71 122.81 15.0Error 2.20 0.21 0.15 0.0Assumed half duration: 1.4Mechanism information Exponent for moment tensor: 23 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 0.020 4.110 -4.130 1.350 0.710 0.570Error 0.410 0.420 0.570 2.010 1.200 0.410Mw = 5.0 Scalar Moment = 4.42e+23Fault plane: strike=132 dip=72 slip=6Fault plane: strike=40 dip=84 slip=162Eigenvector: eigenvalue: 4.58 plunge: 17 azimuth: 355(T)Eigenvector: eigenvalue: -0.32 plunge: 71 azimuth: 204(N)Eigenvector: eigenvalue: -4.26 plunge: 9 azimuth: 87(P)Comments :The solution is strikeslip, with P and T axes virtually horizontal, striking north-south and east-west respectively.

46

Hawker, 22nd April 1980Date :1980 April 22Place :Hawker, S.A., Orroroo 1:250000 Map.Surface expression :Nil

Solution Reference :Singh(1985).Hypocentre source :University of AdelaideType of analysis :P wave polarity; Schmidt projection.Magnitudes :ML 3.7Origin time (UTC) :012445.9Hypocentre, Latitude:-32.03 Longitude:138.72 Depth(km):12Mechanism :Normal fault or overthrustNodal plane 1, Strike:038 Dip:42 Slip:-149 Pole, Azimuth:308 Plunge:48Nodal plane 2, Strike:284 Dip:70 Slip:-52 Pole, Azimuth:194 Plunge:20T axis Azimuth:349 Plunge:16N axis Azimuth:090 Plunge:36 Uncertainty:~60°*30°.P axis Azimuth:238 Plunge:51 Zoback Rating:D Fault Plane Rating:5Comments :The solution is poorly constrained. In addition to the normal fault solution presented, thesolution can also be overthrust within the N axis uncertainty.

Station Azimuth Plunge C + D - UMS 11 38 +RPA 59 4 -EDO 61.5 8 -PNA 93 10 -WKA 165 37 -MGR 167 38 -ADT 181 37 -WSA 298 38 -HTT 353 4 +

47

Wilpena, 15th July 1981Date :1981 July 15Place :Wilpena, South Australia; Parachilna 1:250000 Map.Surface expression :Nil

Solution Reference :Greenhalgh et al.(1994)Hypocentre source :Greenhalgh et al.(1994).Type of analysis :P wave polarity, Schmidt projection, S wave amplitude.Magnitudes :ML 3.7Origin time (UTC) :020909.9Hypocentre, Latitude:-31.37 Longitude:138.64 Depth(km):3Mechanism :Vertical faultNodal plane 1, Strike:030 Dip:90 Slip:0 Pole, Azimuth:120 Plunge:00Nodal plane 2, Strike:120 Dip:00 Slip:180 Pole, Azimuth:030 Plunge:90T axis Azimuth:120 Plunge:45N axis Azimuth:030 Plunge:00 Uncertainty:~5°*1°.P axis Azimuth:300 Plunge:45 Zoback Rating:E Fault Plane Rating:1Comments :The solution is tight with critically positioned station polarities, being either a vertical orhorizontal nodal plane. Greenhalgh et al. favour the vertical plane as the fault plane. The Zoback(1992) rating is E as both Pand T axes plunge at 45°. A 45° plunging northwest compression probably did not cause the earthquake; more likely simpleshear on the vertical plane.

Station Azimuth Plunge C + D - EDO 28 6 -PNA 33 5 +ADT 180 37 -UMB 201 5 +NBK 202 38 +CLV 216 41 -RPA 218 37 -WSA 279 38 -

48

Appin, 15th November 1981Date :1981 November 15Place :Appin, near Sydney, NSW; Wollongong 1:250000 Map.Surface expression :Nil

Solution Reference :Denham et al.(1982).Hypocentre source :AGSOType of analysis :P wave polarityMagnitudes :ML 4.6; mb 4.3.Origin time (UTC) :165810.4Hypocentre, Latitude:-34.249 Longitude:150.897 Depth(km):14.4Mechanism :OverthrustNodal plane 1, Strike:182 Dip:48 Slip:87 Pole, Azimuth:092 Plunge:42Nodal plane 2, Strike:007 Dip:42 Slip:94 Pole, Azimuth:277 Plunge:48T axis Azimuth:052 Plunge:87N axis Azimuth:184 Plunge:02 Uncertainty:~45°*1°.P axis Azimuth:275 Plunge:03 Zoback Rating:D Fault Plane Rating:4Comments :One nodal plane of the overthrust solution is well constrained, the other not so. However, the Paxis remains horizontal, varying through about 30° between WSW and WNW. Two stations, LER and SFF are inconsistentwith the solution.The fault plane solution of an aftershock which occurred four days later on 19 November was very poorly constrained(Denham et al., 1982). Although an overthrust similar to that of the main shock is the solution shown, a strike slip solutionis also possible from the few available station polarities. Denham et al. suggest that the location of the aftershock to thenorthwest of the main earthquake and at a shallower depth favours the east dipping plane of the main shock as the faultplane.

(a)Station Azimuth Plunge C + D - BRS 13 43 +COO 14 42 +WER 140 14 -SAV 199 43 +STG 204 44 +SFF 206 45 -RIV 209 14 -MEG 221 20 -SBR 224 41 +CNB 230 44 -TOO 234 41 +GVL 235 41 +CAN 238 43 -LER 243 19 +BFD 247 42 -BWA 265 40 -YOU 269 40 -STK 288 42 -JNL 301 19 -WRA 310 45 +ISQ 320 42 +CTA 342 43 +

(b)AVO 58 17 -RIV 212 8 -MEG 221 19 -SBR 226 40 +LER 244 19 -BWA 266 40 -JNL 300 17 -

49

Suggan Buggan, 30th November 1981Date :1981 November 30Place :Suggan Buggan, Snowy Mtns, southeast NSW; Tallangatta 1:250000 Map.Surface expression :Nil

Solution Reference :Bock and Denham(1983).Hypocentre source :Bock and Denham(1983).Type of analysis :P wave polarityMagnitudes :3.7Origin time (UTC) :020908Hypocentre, Latitude:-36.69 Longitude:148.33 Depth(km):7Mechanism :Strikeslip.Nodal plane 1, Strike:230 Dip:80 Slip:-174 Pole, Azimuth:140 Plunge:10Nodal plane 2, Strike:139 Dip:86 Slip:-9 Pole, Azimuth:049 Plunge:04T axis Azimuth:186 Plunge:05N axis Azimuth:290 Plunge:78 Uncertainty:~60°*2°P axis Azimuth:095 Plunge:10 Zoback Rating:D Fault Plane Rating:4Comments :One nodal plane of the strikeslip solution is well constrained, but not the other. Station LER isanomalous, as it was for the 15 November 1981 Appin earthquake (but not the 19 November aftershock). Bock andDenham consider that the earthquake may have occurred on the Moyangul River Fault, which would make the northwesttrending nodal plane the fault plane, and the strikeslip motion sinistral.

Station Azimuth Plunge C + D - YOU 1 44 +BWA 10 44 -CAN 23 25 +LER 25 44 -JNL 26 46 +CNB 30 44 +WER 35 44 +SBR 38 44 +AVO 42 44 -WAW 42.5 14 +TOM 230 44 +KGO 246 43 -TOO 248 44 -GVL 252 44 -BFD 265 42 -DRM 286 16 -

50

Wonnangatta, 21st Nobember 1982Date :1982 November 21Place :Wonnangatta, east Victoria; Warburton 1:250000 MapSurface expression :Nil

Solution Reference :Denham et al.(1985).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection; aftershock distribution.Magnitudes :ML 5.4, mb 4.8.Origin time (UTC) :113418.7Hypocentre, Latitude:-37.205 Longitude:146.956 Depth(km):17Mechanism :OverthrustNodal plane 1, Strike:357 Dip:52 Slip:52 Pole, Azimuth:268 Plunge:38Nodal plane 2, Strike:229 Dip:51 Slip:129 Pole, Azimuth:139 Plunge:39T axis Azimuth:205 Plunge:61N axis Azimuth:022 Plunge:29 Uncertainty:1°*1°.P axis Azimuth:113 Plunge:01 Zoback Rating:B Fault Plane Rating:1Comments :The solution is very well constrained, an overthrust with ESE trending P axis. Denham et al.found that although there is considerable scatter in the distribution of the aftershocks, the evidence suggests that the north-south striking nodal plane is associated with the faulting. Note that for the north-south plane as the fault plane, east side isup.

Station Azimuth Plunge C + D - YOU 22 44 +BWA 28 44 +COO 29 49 +DRT 35 20 +CAH 37 42 +CAN 41 40 -RIV 43 41 +SBR 48 41 -LER 49 41.5 +MEG 51 40.5 -WAM 57 41 -TAU 176 40 +SAV 178 40 +TRR 181 40 +SPK 183 40 +SFF 186 40 +MOO 190 40 +STG 196 40 +JEN 201 19 +PAT 211 19 +TOM 215 19 +MIC 219 19 +LIL 249 40 +TOO 253 19 -PNA 253 40 +PIT 257 40 +BFD 271 40 +PEG 276 39 -KLG 286 52 +ADT 288 41 -MEK 294 58 +STK 320 42 -WB2 326 50 -CTA 356 48 +

51

West Wyalong, 26 November 1982Date :1982 November 26Place :West Wyalong, central NSW; Forbes 1:250000 map.Surface expression :Nil

Solution Reference :Denham et al.(1985)Hypocentre source :AGSOType of analysis :P wave polarity; Schmidt projectionMagnitudes :ML 4.6Origin time (UTC) :001114Hypocentre, Latitude:-33.94 Longitude:147.25 Depth(km):04Mechanism :OverthrustNodal plane 1, Strike:192 Dip:41 Slip:59 Pole, Azimuth:102 Plunge:49Nodal plane 2, Strike:051 Dip:56 Slip:114 Pole, Azimuth:321 Plunge:34T axis Azimuth:015 Plunge:69N axis Azimuth:217 Plunge:21 Uncertainty:~8°*1°.P axis Azimuth:124 Plunge:07 Zoback Rating:B Fault Plane Rating:2Comments :The southeast dipping nodal plane is well constrained. The west dipping nodal plane isconstrained to pass as close as possible to dilatation stations HWK and PNA which are anomalous but close to the nodalplane, making the solution tight. The P axis is horizontal on a southeast azimuth.

Station Azimuth Plunge C + D - Q14 34 46 -BRS 38 45 -CDO 49 46 -RIV 87 41 -WER 90 40.5 -AVO 99 41 -BWA 110 17 -CAH 112 40 -MEG 116 40 -LER 110 17 -CNB 130 40 -CAN 131 39 -WAM 151 40 -TAO 154 40 -CBR 158 40 -DRT 176 41 -TOO 203 43 +BFD 231 40 +WKA 246 41 +AOT 260 46 +WRE 280 44 +EOO 283 44 +HWA 284 41 +STK 292 40 +UMB 299 44 +ASP 311 45 +

52

Tasman Sea, 25th November 1983Date :1983 November 25Place :Tasman Sea, east of Flinders Island.Surface expression :Nil

Solution Reference :Denham(1985).Hypocentre source :USGSType of analysis :P wave polarity, synthetic seismograms, Schmidt projection.Magnitudes :mb 6.0, MS 5.8.Origin time (UTC) :195607.8Hypocentre, Latitude:-40.451 Longitude:155.507 Depth(km):18Mechanism :OverthrustShort-period P wave polarityNodal plane 1, Strike:208 Dip:17 Slip: Pole, Azimuth:117 Plunge:73Nodal plane 2, Strike:013 Dip:74 Slip: Pole, Azimuth:282 Plunge:16T axis Azimuth:276 Plunge:61N axis Azimuth:014 Plunge:04 Uncertainty:~12°*1°.P axis Azimuth:106 Plunge:29Long-period P wave polarity, Synthetic seismogramsNodal plane 1, Strike:208 Dip:17 Slip:105 Pole, Azimuth:117 Plunge:73Nodal plane 2, Strike:013 Dip:74 Slip:86 Pole, Azimuth:282 Plunge:16T axis Azimuth:208 Plunge:82N axis Azimuth:049 Plunge:07 Uncertainty:Synthetic seismogramsP axis Azimuth:319 Plunge:03The separation of the N axes from the two methods is approximately 35°.

Zoback Rating:D Fault Plane Rating:4Comments :The short-period P wave solution contains many anomalous readings. Apart from that, onenodal plane is well defined. The other is not so well defined, the strike depending on which stations are included or ignoredas anomalous. An alternative orientation would rotate the strike from 014° to 024°. The N axis azimuth is at 014°.The long-period P wave/synthetic seismogram solution is rotated onto a northeast-southwest azimuth, with the N axis at049°.


Zoback Rating:C Fault Plane Rating:3112583B SOUTHEAST OF AUSTRALIA Date (y/m/d): 1983/11/25Information on data used in inversion Wave nsta nrec cutoffBody 18 42 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 19 56 8.50 -40.44 155.58 24.0 6.0 5.8CMT 19 56 16.30 -39.95 156.36 24.3Error 0.30 0.04 0.05 1.8Assumed half duration: 3.5Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 8.930 -7.440 -1.490 -5.320 -0.980 -4.340Error 0.190 0.270 0.300 0.790 0.620 0.210Mw = 6.0 Scalar Moment = 1.08e+25

53

Fault plane: strike=52 dip=31 slip=74Fault plane: strike=251 dip=60 slip=100Eigenvector: eigenvalue: 10.52 plunge: 73 azimuth: 185(T)Eigenvector: eigenvalue: 0.56 plunge: 8 azimuth: 66(N)Eigenvector: eigenvalue: -11.08 plunge: 15 azimuth: 334(P)Comments :The CMT solution is overthrust but with the N axis rotated clockwise still further to 066°.

Station Azimuth Plunge C + D - KOU 23 44 +PVC 30 48 +

32 43 -MSV 47 52 +AFI 56 55 -

88 26 -93 29 -101 23 -116 18 -120 16 -140 62 -173 23 -180 53 +181 57 -209 58 +

TAU 244 12 +246 14 -248 14 -252 12 -255 11 +259 12 -271 50 +273 50 -273 52 -281 20 +280 50 -281 50 +283 42 +285 14 -285 20 +286 14 -287 18 +287 24 +286 52 +286 71 +287 54 -287 82 +292 82.5 +292 83.5 +292 24 +292 26 +292.5 49 +292.5 53 +292.5 71 +292.5 62 -292.5 64 -292.5 66 -293 82.5 +295 29 +296.5 57 +296.5 61 +296.6 63 +297 58 -297 64 +298 26 -303 23 +303 27 +303 58 -

54

303 63 +305 12 -306 47 +306 66 +306 68 +307 70 -307 14 -309 60 +309 66 +311 14 -312 50 +312 60 +311 70 -314 11 -314 13 -314 53 +314 67 +315 14 -315 19 +315 53 +315 66 +317 12 -317 70 +318 66 +320 47 +320 60 +320 70 +322 60 +322 66 -322 70 +324 65 -326 67 +326 69 +330 13 -330 67 -330 69 -334 45 +336 24 +338 43 +341 17 +341 53 +341 68 +345 68 +345 20 +345 53 +345 68 +246 21 +347 69 +347 20 +348 17 -348 69 -349 21 -

55

Beltana, 29th December 1983Date :1983 December 29Place :Beltana, east South Australia; Copley 1:250000 Map.Surface expression :Nil

Solution Reference :Greenhalgh and Denham(1986)Hypocentre source :University of AdelaideType of analysis :P wave polarity; Schmidt projection, aftershock pattern.Magnitudes :ML 4.4; mb 5.1.Origin time (UTC) :174201.16Hypocentre, Latitude:-30.794 Longitude:138.405 Depth(km):20.4Mechanism :StrikeslipNodal plane 1, Strike:325 Dip:83 Slip:8 Pole, Azimuth:235 Plunge:07Nodal plane 2, Strike:235 Dip:82 Slip:174 Pole, Azimuth:145 Plunge:08T axis Azimuth:190 Plunge:10N axis Azimuth:011 Plunge:85 Uncertainty:Tight, anomalous stations.P axis Azimuth:097 Plunge:01 Zoback Rating:C Fault Plane Rating:2Comments :The strikeslip solution is tight with anomalous stations. Observatory station TOO is held in thecorrect quadrant, making JEN and PEG close to the nodal plane but anomalous. Station UMB is close to the nodal planebut anomalous. Stations WKA and MGR, reported to be definite dilatations, are effectively ignored in the solution infavour of TOO and BFD. The foreshock and aftershock sequence favours the northwest striking plane as the fault plane.Both P and T axes are horizontal. From the solution alone, there is no reason to favour a compressive stress origin overtensional stress or simple shear.

Station Azimuth Plunge C + D - PNA 9 6 +CTA 35 56 +UMB 48 13 -RTQ 68 41 -WRG 77 5 -CMS 101 40 -YOU 106 38 -STK 112 40 -LER 115 41 -MEG 117 40 -CAN 120 40 -CAB 125 40 -KHA 127 40 -JEN 141 40 -TOO 139 39 +PEG 144 40 -BFD 153 39 +MGR 163 39 -WKA 167 39 -ADE 167 43 +HTT 171 38 +NBK 188 39 +RPA 203 40 +CLV 207 39 +MUN 260 49 -MEK 278 46 -HKW 286 40 -NAU 287 56 -WBN 293 56 -MBL 302 50 -ASPO 329 58 -KNA 328 52 -MTN 340 59 +WCB 340 42 +

56

Oolong, 9th August 1984Date :1984 August 09Place :Oolong, southeast NSW; Goulburn 1:250000 MapSurface expression :Nil

Solution Reference :McCue et al.(1989).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 4.3Origin time (UTC) :063014.0Hypocentre, Latitude:-34.81 Longitude:149.17 Depth(km):05Mechanism :Overthrust. (Vertical fault parameters below)Nodal plane 1, Strike:346 Dip:45 Slip: Pole, Azimuth:256 Plunge:45Nodal plane 2, Strike:200 Dip:50 Slip: Pole, Azimuth:110 Plunge:40T axis Azimuth:186 Plunge:73N axis Azimuth:006 Plunge:21 Uncertainty:Anomalous stations.P axis Azimuth:274 Plunge:03 Zoback Rating:X Fault Plane Rating:XComments :McCue et al. were unable to obtain a unique solution. The two solutions shown, an overthrustand a vertical fault, are very uncertain, with anomalous stations scattered throughout the plot, caused by the emergence andhence unreliability of the Pn arrivals.Neither solution should be used as a stress field indicator, and should not appear on the Australian Stress Map.

Solution Reference :McCue et al.(1989)Type of analysis :P wave polarity, Schmidt projection.Mechanism :Vertical faultNodal plane 1, Strike:032 Dip:83 Slip: Pole, Azimuth:302 Plunge:07Nodal plane 2, Strike:129 Dip:46 Slip: Pole, Azimuth:039 Plunge:44T axis Azimuth:329 Plunge:36N axis Azimuth:205 Plunge:45 Uncertainty:Anomalous stationsP axis Azimuth:088 Plunge:23

Station Azimuth Plunge C + D - CAN 16 9 +JNL 36 23 -WER 54 39 -RIV 60 37 +AVO 69 22 -WAM 189 23 +CBR 209 22 +TAO 221 22.5 -KHA 211 37 -TOM 217 43 -TOO 227 43 -OOLO 224 56 +GVL 231 43 -BFD 246 43 -IVY 291 7 -STK 296 44 +CMSO 320 44 -CNB 343 5 -

57

Lake Frome, 28th May 1985Date :1985 May 28Place :Lake Frome, east South Australia; Parachilna 1:250000 MapSurface expression :Nil

Solution Reference :McCue(1989)Hypocentre source :AGSOType of analysis :P wave polarity, ; listing only, projection not included.Magnitudes :ML 4.0Origin time (UTC) :040011.8Hypocentre, Latitude:-31.76 Longitude:139.42 Depth(km):05Mechanism :Nodal plane 1, Strike:228 Dip:70 Slip:32 Pole, Azimuth: Plunge:Nodal plane 2, Strike:126 Dip:61 Slip:156 Pole, Azimuth: Plunge:T axis Azimuth:356 Plunge:8N axis Azimuth:258 Plunge:52 Uncertainty:not seenP axis Azimuth:92 Plunge:39 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1985, listing only, projection not included

58

Norseman, 28th July 1985Date :1985 July 28Place :Norseman, south Western Australia, Norseman 1:250000 MapSurface expression :Nil

Solution Reference :McCue(1989)Hypocentre source :AgsoType of analysis :P wave polarity, listing only projection not includedMagnitudes :ML 5.4Origin time (UTC) :074937.3Hypocentre, Latitude:-32.51 Longitude:122.22 Depth(km):10Mechanism :Nodal plane 1, Strike:216 Dip:46 Slip:126 Pole, Azimuth: Plunge:Nodal plane 2, Strike:350 Dip:52 Slip:57 Pole, Azimuth: Plunge:T axis Azimuth:104 Plunge:2N axis Azimuth:14 Plunge:30 Uncertainty:P axis Azimuth:198 Plunge:63 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1985, listing only, projection not included

59

Canberra, 28th November 1985Date :1985 November 28Place :Canberra, ACT, Canberra 1:250000 MapSurface expression :Nil

Solution Reference :McCue(1989)Hypocentre source :AGSOType of analysis :P wave polarity, listing only, projection not includedMagnitudes :ML 2.4Origin time (UTC) :205112.2Hypocentre, Latitude:-35.28 Longitude:149.11 Depth(km):02Mechanism :Nodal plane 1, Strike:245 Dip:70 Slip-20 Pole, Azimuth: Plunge:Nodal plane 2, Strike:342 Dip:80 Slip:-145 Pole, Azimuth: Plunge:T axis Azimuth:209 Plunge:28N axis Azimuth: 358 Plunge:58 Uncertainty:P axis Azimuth:111 Plunge:14 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1985, listing only, projection not included.

60

Colo, 20th February 1986Date :1986 February 20Place :Upper Colo, east NSW, Sydney 1:250000 MapSurface expression :Nil

Solution Reference :Gregson and Moiler(1990)Hypocentre source :AGSOType of analysis :P wave polarity, listing only, projection not included.Magnitudes :3.9Origin time (UTC) :214355.3Hypocentre, Latitude:-33.30 Longitude:150.60 Depth(km):02Mechanism :Nodal plane 1, Strike:40 Dip:70 Slip:-158 Pole, Azimuth: Plunge:Nodal plane 2, Strike:302 Dip:70 Slip:-22 Pole, Azimuth: Plunge:T axis Azimuth:262 Plunge:30N axis Azimuth:82 Plunge:60 Uncertainty:P axis Azimuth:353 Plunge:0 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1986, listing only, projection not included.

61

Marryat Creek, 30th March 1986Date :1986 March 30Place :Marryat Creek, north South Australia, Alberga 1:250000 Map.Surface expression :A surface fault scarp that is in the shape of a boomerang (convex to the northeast) ~13 km long,with a maximum displacement of 0.8 m.

Solution Reference :McCue et al.(1987).Hypocentre source :McCue et al.(1987).Type of analysis :P wave polarity, Schmidt projection.Magnitudes :mb 5.7; MS 5.8; ML 6.0Origin time (UTC) :085348Hypocentre, Latitude:-26.22 Longitude:132.82 Depth(km):00?Mechanism :Overthrust/strikeslipNodal plane 1, Strike:350 Dip:58 Slip:152 Pole, Azimuth:260 Plunge:32Nodal plane 2, Strike:096 Dip:67 Slip:36 Pole, Azimuth:003 Plunge:23T axis Azimuth:314 Plunge:41N axis Azimuth:122 Plunge:48 Uncertainty:1°*1°, tightP axis Azimuth:220 Plunge:04 Zoback Rating:B Fault Plane Rating:1Comments :The solution is tight apart from one anomalous polarity. The P axis is horizontal on a northeast-southwest azimuth.The surface fault scarp has a north-south section and an east-west section, with sinistral and dextralcomponents of motion respectively, in agreement with both nodal planes of the solution, but McCue et al. conclude that theinitial fault motion, as recorded by seismograph stations and from which the solution is derived, was associated with theeast-west limb of the fault.


Zoback Rating:C Fault Plane Rating:3033086A SOUTH AUSTRALIA Date (y/m/d): 1986/3/30Information on data used in inversion Wave nsta nrec cutoffBody 12 26 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 8 53 53.20 -26.23 132.70 10.0 5.7 5.8CMT 8 54 1.90 -25.63 132.82 15.0Error 0.50 0.07 0.04 0.0Assumed half duration: 2.7Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 4.360 -0.700 -3.660 0.370 0.910 1.850Error 0.120 0.140 0.170 0.460 0.500 0.120Mw = 5.7 Scalar Moment = 4.57e+24Fault plane: strike=145 dip=42 slip=76Fault plane: strike=344 dip=50 slip=103Eigenvector: eigenvalue: 4.53 plunge: 80 azimuth: 311(T)Eigenvector: eigenvalue: 0.07 plunge: 10 azimuth: 156(N)Eigenvector: eigenvalue: -4.60 plunge: 4 azimuth: 65(P)

62

Comments :The Harvard cmt solution is an overthrust on a NNW-SSE azimuth, agreeing with neither north-south nor east-west surface fault segments, but could represent more of the "full picture", or combination of both faultsegments.

Station Azimuth Plunge C + D- 1 64 +13 29 -21 25 -42 48 -43 52 -94 34 -98 38 -109 37 -117 33 +120 37 +126 46 +128 40 +139 34 +142 30 +146 30 +146 34 -151 32 +151 33 -152 48 -152 35 +152 30 -157 30 -207 62 -236 36 +242 36 -251 34 -256 35 -272 28 +292 32 +305 56 +312 53 +322 66 +326 63 +326 64 +326 65 +334 65 +334 67 +340 31 +340 65 +340 67 +347 49 +347 63 +347 65 +347 49 +350 66 +358 68 -

63

Marryat Creek, 11 July 1986Date :1986 July 11Place :Marryat Creek, north South Australia, Alberga 1:250000 Map.Surface expression :Nil

Solution Reference :Gregson and Moiler(1990)Hypocentre source :AGSOType of analysis :P wave polarity, listing only, projection not included.Magnitudes :mb 5.6, MS 5.4Origin time (UTC) :071754.7Hypocentre, Latitude:-26.262 Longitude:132.511 Depth(km):05Mechanism :Nodal plane 1, Strike:0 Dip:49 Slip:156 Pole, Azimuth: Plunge:Nodal plane 2, Strike:106 Dip:68 Slip:37 Pole, Azimuth: Plunge:T axis Azimuth:230 Plunge:11N axis Azimuth:130 Plunge:44 Uncertainty:P axis Azimuth:332 Plunge:44 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1986, listing only, projection not included.

64


Zoback Rating:C Fault Plane Rating:3071186A SOUTH AUSTRALIA Date (y/m/d): 1986/7/11Information on data used in inversion Wave nsta nrec cutoffBody 14 26 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 7 17 58.40 -26.22 132.84 10.0 5.6 5.4CMT 7 18 8.70 -25.52 132.64 15.0Error 0.80 0.10 0.06 0.0Assumed half duration: 1.7Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 0.640 0.680 -1.320 -0.240 0.250 0.400Error 0.040 0.070 0.070 0.140 0.160 0.040Mw = 5.3 Scalar Moment = 1.17e+24Fault plane: strike=209 dip=57 slip=156Fault plane: strike=313 dip=70 slip=36Eigenvector: eigenvalue: 0.91 plunge: 39 azimuth: 175(T)Eigenvector: eigenvalue: 0.53 plunge: 50 azimuth: 339(N)Eigenvector: eigenvalue: -1.44 plunge: 8 azimuth: 78(P)Comments :The cmt solution is strikeslip/overthrust with a horizontal P axis, virtually east-west.

65

Tennant Creek, 9th January 1987Date :1987 January 09Place :Central Northern Territory, Bonney Well 1:250000 MapSurface expression :Nil


Zoback Rating:C Fault Plane Rating:3010987C N TERRITORY, AUSTRALIA Date (y/m/d): 1987/1/9Information on data used in inversion Wave nsta nrec cutoffBody 4 9 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 11 27 11.40 -20.03 133.71 10.0 5.1 0.0CMT 11 27 16.70 -20.03 133.71 15.0Error 2.30 0.00 0.00 0.0Assumed half duration: 1.8Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 1.000 -0.120 -0.880 0.290 1.100 0.630Error 0.220 0.200 0.340 0.600 0.640 0.210Mw = 5.4 Scalar Moment = 1.61e+24Fault plane: strike=125 dip=32 slip=41Fault plane: strike=359 dip=69 slip=115Eigenvector: eigenvalue: 1.67 plunge: 58 azimuth: 304(T)Eigenvector: eigenvalue: -0.13 plunge: 24 azimuth: 169(N)Eigenvector: eigenvalue: -1.54 plunge: 20 azimuth: 70(P)Comments :The overthrust earthquake occurred on either a north-south or northwest-southeast strikingfault. The P axis plumges at 20°.

66

Cadoux, 7th March 1987Date :1987 March 07Place :Cadoux, southwest Western Australia, Bencubbin 1:250000 Map.Surface expression :Nil

Solution Reference :Michael-Leiba and Dent(1991).Hypocentre source :AGSOType of analysis :P wave polarity, listing only, projection not included.Magnitudes :ML 4.5Origin time (UTC) :053807.7Hypocentre, Latitude:-30.77 Longitude:117.09 Depth(km):05Mechanism :Nodal plane 1, Strike:210 Dip:51 Slip:98 Pole, Azimuth: Plunge:Nodal plane 2, Strike:17 Dip:40 Slip:80 Pole, Azimuth: Plunge:T axis Azimuth:173 Plunge:80N axis Azimuth:26 Plunge: 5 Uncertainty:P axis Azimuth:296 Plunge:6 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1987, projection not included.

67

Lithgow, 24th June 1987Date :1987 June 24Place :Lithgow, east NSW, Sydney 1:250000 Map.Surface expression :Nil

Solution Reference :Michael-Leiba and Dent(1991).Hypocentre source :AGSOType of analysis :P wave polarity, listing only, projection not included.Magnitudes :ML 4.3Origin time (UTC) :150455.2Hypocentre, Latitude:-33.432 Longitude:150.149 Depth(km):05Mechanism :Nodal plane 1, Strike:202 Dip:74 Slip: -162 Pole, Azimuth: Plunge:Nodal plane 2, Strike:107 Dip:63 Slip: -11 Pole, Azimuth: Plunge:T axis Azimuth:336 Plunge:1N axis Azimuth:230 Plunge:57 Uncertainty:P axis Azimuth:68 Plunge:37 Zoback Rating:X Fault Plane Rating:XComments :Australian seismological report 1987,listing only, projection not included.

68

Nhill, 22nd December 1987Date :1987 December 22Place :Nhill, west Victoria, Horsham 1:250000 MapSurface expression :Nil

Solution Reference :McCue et al.(1990)Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 4.9Origin time (UTC) :150630.7Hypocentre, Latitude:-36.11 Longitude:141.54 Depth(km):06Mechanism :Strikeslip/normal.Nodal plane 1, Strike:050 Dip:50 Slip: -169 Pole, Azimuth:320 Plunge:40Nodal plane 2, Strike:313 Dip:80 Slip: -35 Pole, Azimuth:223 Plunge:10T axis Azimuth:008 Plunge:13N axis Azimuth:120 Plunge:48 Uncertainty:Anomalous stationsP axis Azimuth:264 Plunge:35 Zoback Rating:X Fault Plane Rating:XComments :The publisted solution is strikeslip/normal, with T axis virtually horizontal and P axis plungingat 35° to the west. There are anomalous station compressions close to a nodal plane and one mid-quadrant. However analternative overthrust solution with similar uncertainty also is possible, with P axis virtually horizontal, oriented southeast,parameters shown below.

Solution Reference :AlternativeType of analysis :P wave polarities of McCue et al.(1990).Mechanism :OverthrustNodal plane 1, Strike:204 Dip:36 Slip: Pole, Azimuth:114 Plunge:54Nodal plane 2, Strike:062 Dip:59 Slip: Pole, Azimuth:332 Plunge:31T axis Azimuth:016 Plunge:68N axis Azimuth:231 Plunge:20 Uncertainty:Anomalous stations.P axis Azimuth:136 Plunge:13Station Azimuth Plunge C + D-

74 4 -77 31 +78 27 +81 25 +83 35 +84 32 -86 28 -87 33 -90 34 -115 37 -140 29 +275 6 -281 7 +298 36 -315 37 -315 41 -321 38 +325 38 +330 43 +340 33 +347 40 +359.5 38 +

69

Tennant Creek, 22nd January 1988Date :1988 January 22Place :Tennant Creek, central Northern Territory, Tennant Creek 1:250000 MapSurface expression :Complex surface faulting. Jones et al.(1991) described the fault scarp, including the following:The rupture at 0036UTC appears to have begun near the cusp on the Lake Surprise Fault, and propogated mainlynorthwest. The easterly extent of this propogation is limited by the account of Mr Kevin Holt of NTGAS, who observed nodamage to the gas pipeline before the second mainshock. Therefore, the maximum length of rupture is the distance from thepipeline to the western end of the Kunayungku scarp, 22 km.

Solution Reference :Jones et al.(1991).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, relative P wave amplitudes, fault scarp observations, andtrench excavations.Magnitudes :mb 6.1, MS 6.3, ML 6.3.Origin time (UTC) :003601.0Hypocentre, Latitude:-19.81 Longitude:133.98 Depth(km):06Mechanism :OverthrustNodal plane 1, Strike:117 Dip:55 Slip:72 Pole, Azimuth:027 Plunge:35Nodal plane 2, Strike:326 Dip:38 Slip:114 Pole, Azimuth:236 Plunge:52T axis Azimuth:338 Plunge:73N axis Azimuth:119 Plunge:14 Uncertainty:Non-orthogonal, tightP axis Azimuth:220 Plunge:09 Zoback Rating:B Fault Plane Rating:2Comments :The solution is tight, but with anomalous station polarities. If the CTAO broadband stationcompression is adopted, then the nodal plane is drawn as close as possible to the anomalous PMG. Surface thrusting,southern block over northern block, described by Jones et al., favours the plane dipping southwest as the fault plane. The Paxis is horizontal, azimuth southwest. The observed thrusting is described as "almost pure". If station PMG were favouredin the solution over CTAO, a thrust solution would still result, but with a strong sinistral (left lateral) component, which isnot observed in the surface faulting.


Zoback Rating:C Fault Plane Rating:3012288A NORTHERN TERRITORY, AUSTRALIA Date (y/m/d): 1988/1/22Information on data used in inversion Wave nsta nrec cutoffBody 16 41 45Mantle 10 21 135Timing and location information hr min sec lat lon depth mb MsPDE 0 35 57.90 -19.90 133.81 5.0 6.1 6.3CMT 0 36 2.80 -19.69 133.81 15.0Error 0.30 0.02 0.02 0.0Assumed half duration: 5.6Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 2.510 -2.450 -0.060 0.570 -0.320 0.950Error 0.040 0.030 0.050 0.150 0.100 0.030Mw = 6.2 Scalar Moment = 2.73e+25Fault plane: strike=286 dip=38 slip=85Fault plane: strike=112 dip=52 slip=94Eigenvector: eigenvalue: 2.59 plunge: 83 azimuth: 42(T)

70

Eigenvector: eigenvalue: 0.27 plunge: 3 azimuth: 290(N)Eigenvector: eigenvalue: -2.86 plunge: 7 azimuth: 200(P)Comments :The southwest dipping plane, the fault plane, is virtually the same as that of Jones et al.See also Choy and Bowman(1990), who determined the focal mechanisms for the four main earthquakes from broadbanddisplacement records of P waves from teleseismically recorded data, and McCaffrey(1989) who obtained waveforminversions of the three main earthquakes.

Station Azimuth Plunge C + D- PMG 54 46 -CTAO 94 35 +

134 55 +143 54 +153 54 +153 58 +166 45 +166 68 +

ASP 180 45 -MAW 202 68 +NWAO 202 68 +MUN 233 51 -LEM 294 55 +

306 73 +322 63 -322 66 +

71

Tennant Creek, 22nd January 1988Date :1988 January 22Place :Tennant Creek, central Northern Territory, Tennant Creek 1:250000 MapSurface expression :Probable extension of surface fault scarp caused by 0036 UTC earthquake.

Solution Reference :Jones et al.(1991)Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, surface fault scarp.Magnitudes :mb 6.1, MS 6.4, ML 6.4.Origin time (UTC) :035728.5Hypocentre, Latitude:-19.83 Longitude:133.98 Depth(km):04Mechanism :Strikeslip/overthrustNodal plane 1, Strike:152 Dip:73 Slip: 154 Pole, Azimuth:062 Plunge:17Nodal plane 2, Strike:250 Dip:66 Slip: 19 Pole, Azimuth:160 Plunge:24T axis Azimuth:110 Plunge:30N axis Azimuth:299 Plunge:58 Uncertainty:~8°*4°.P axis Azimuth:203 Plunge:04 Zoback Rating:C Fault Plane Rating:3Comments :The solution is a tight strikeslip with overthrust. One station compression is situated right on theintersection of the nodal planes, the Null axis, and can fit into either of the compressional quadrants. However the strikeslipnature of the solution relies heavily on two teleseismic station dilatations to constrain one of the nodal planes, while ananomalous station dilatation of the same or a nearby station was ignored in the first of the Tennant creek earthquakesolutionsJones et al. consider that this second earthquake fractured the western ENE trending limb of the Lake Surprise Fault, wherethe northern block was upthrust, and there was a much stronger sinistral strikeslip component. The Fault plane solutionconforms with this surface faulting pattern if the ENE trending nodal plane is the fault plane.Jones et al. further suggest that fracture extended to the eastern limb of the Surprise Fault, so involving rupture on two faultsurfaces of opposing dip, to the SSW (east side) and to the NNW (west side).The P axis is horizontal on a SSW azimuth.


Zoback Rating:C Fault Plane Rating:3012288B NORTHERN TERRITORY, AUSTRALIA

Date (y/m/d): 1988/1/22Information on data used in inversion Wave nsta nrec cutoffBody 12 33 45Mantle 9 18 135Timing and location information hr min sec lat lon depth mb MsPDE 3 57 25.10 -19.81 133.91 5.0 6.1 6.4CMT 3 57 31.30 -19.66 133.82 15.0Error 0.30 0.02 0.02 0.0Assumed half duration: 5.6Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 2.740 -3.540 0.800 0.790 -0.280 1.440Error 0.050 0.040 0.060 0.220 0.150 0.040Mw = 6.3 Scalar Moment = 3.46e+25Fault plane: strike=285 dip=38 slip=88Fault plane: strike=108 dip=52 slip=92

72

Eigenvector: eigenvalue: 2.84 plunge: 83 azimuth: 29(T)Eigenvector: eigenvalue: 1.23 plunge: 2 azimuth: 287(N)Eigenvector: eigenvalue: -4.08 plunge: 7 azimuth: 197(P)Comments :The overthrust CMT solution is similar to the P wave polarity strikeslip/overthrust solution ofJones et al., the difference being in the Null axis location. The P wave solution Null axis is at azimuth 299°, plunge 58°,and the CMT at 287°,2°, a difference of about 56°.The P axis has the same SSW orientation.

Station Azimuth Plunge C + D- 53 57 +55 46 +72 59 +93 35 +134 53 +140 52 +153 53 +153 56 +164 45 +172 68 +181 44 -202 67 +221 50 -230 51 -275 74 +278 74 +292 56 +302 74 +320 67 +336 63 -342 64 -342 65 +342 66 +

73

Tennant Creek, 22nd January 1988Date :1988 January 22Place :Tennant Creek, central Northern Territory, Tennant Creek 1:250000 Map.Surface expression :Extension of surface fault scarp caused by the 0036UTC earthquake.

Solution Reference :Jones et al.(1991)Hypocentre source :AGSOType of analysis :P wave projection, Schmidt projection, surface fault scarp.Magnitudes :mb 6.5, MS 6.7, ML 6.7.Origin time (UTC) :120500.6Hypocentre, Latitude:-19.84 Longitude:133.99 Depth(km):05Mechanism :OverthrustNodal plane 1, Strike:132 Dip:36 Slip:107 Pole, Azimuth:042 Plunge:54Nodal plane 2, Strike:291 Dip:56 Slip:78 Pole, Azimuth:201 Plunge:34T axis Azimuth:160 Plunge:76N axis Azimuth:298 Plunge:08 Uncertainty:~90°*30°.P axis Azimuth:031 Plunge:10 Zoback Rating:D Fault Plane Rating:5Comments :As drawn with one station dilatation anomalous, The Null axis uncertainty is very big. The Paxis remains approximately horizontal but can vary from north through northeast. The solution can be held so that theanomalous station is on the nodal plane and no longer anomalous, which reduces the Null axis uncertainty to just the othernodal plane, but still about 90°, see alternative solution below.

Solution Reference :AlternativeType of analysis :P wave polarities of Jones et al.(1991).Mechanism :OverthrustNodal plane 1, Strike:288 Dip:67 Slip: Pole, Azimuth:198 Plunge:23Nodal plane 2, Strike:108 Dip:23 Slip: Pole, Azimuth:018 Plunge:67T axis Azimuth:198 Plunge:69N axis Azimuth:108 Plunge:00 Uncertainty:~88°*1°.P axis Azimuth:018 Plunge:21

This earthquake was the largest of the series. Jones et al. proposed that the extent of its fracture included all of thesoutheastern Lake Surprise Fault surface and almost certainly broke across the pipeline.


Zoback Rating:C Fault Plane Rating:3012288C NORTHERN TERRITORY, AUSTRALIA Date (y/m/d): 1988/1/22Information on data used in inversion Wave nsta nrec cutoffBody 15 38 45

74

Mantle 7 19 135Timing and location information hr min sec lat lon depth mb MsPDE 12 4 57.50 -19.88 133.88 5.0 6.5 6.7CMT 12 5 3.40 -19.76 133.89 15.0Error 0.30 0.02 0.02 0.0Assumed half duration: 7.8Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 9.140 -7.810 -1.320 -0.010 -0.380 3.270Error 0.110 0.100 0.130 0.580 0.420 0.100Mw = 6.6 Scalar Moment = 9.16e+25Fault plane: strike=290 dip=45 slip=87Fault plane: strike=115 dip=45 slip=93Eigenvector: eigenvalue: 9.15 plunge: 88 azimuth: 102(T)Eigenvector: eigenvalue: 0.02 plunge: 2 azimuth: 293(N)Eigenvector: eigenvalue: -9.17 plunge: 0 azimuth: 203(P)Comments :The CMT solution is an overthrust similar to that obtained by Jones et al.

Station Azimuth Plunge C + D- 53 46 -93 33 +130 60 +134 54 +142 53 +153 54 +155 57 +160 45 +170 68 +180 45 +207 68 +220 51 +231 51 +249 75 +270 76 +277 72 +277 74 +285 76 +293 56 +309 66 +320 67 +338 40 -338 61 +343 62 +348 65 -

75

Tennant Creek, 22nd January 1988Date :1988 January 22Place :Tennant Creek, central Northern Territory, Tennant Creek 1:250000 Map.Surface expression :Nil

Solution Reference :Jones et al.(1991)Hypocentre source :AGSOType of analysis :P wave polarities, Schmidt projectionMagnitudes :mb 5.1, MS 5.3, ML 5.3.Origin time (UTC) :205405.6Hypocentre, Latitude:-19.89 Longitude:134.08 Depth(km):03Mechanism :Strikeslip or overthrustNodal plane 1, Strike:201 Dip:80 Slip: -174 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 110 Dip: 80 Slip: -6 Pole, Azimuth: Plunge:T axis Azimuth:158 Plunge:0N axis Azimuth: Plunge: Uncertainty:Two solutions possibleP axis Azimuth: 67 Plunge:16 Zoback Rating:X Fault Plane Rating:XComments :A strikeslip solution for the earthquake is given, but with many anomalous station readings. Anoverthrust solution can just as easily be drawn with about the same number of anomalous readings.


Zoback Rating:C Fault Plane Rating:3012288D NORTHERN TERRITORY, AUSTRALIA Date (y/m/d): 1988/1/22Information on data used in inversion Wave nsta nrec cutoffBody 10 19 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 20 54 2.90 -19.86 133.99 5.0 5.8 5.0CMT 20 54 14.40 -19.02 133.66 15.0Error 1.40 0.14 0.07 0.0Assumed half duration: 1.9Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 1.190 -0.670 -0.520 0.550 0.550 0.480

76

Error 0.070 0.070 0.090 0.240 0.170 0.070Mw = 5.3 Scalar Moment = 1.31e+24Fault plane: strike=333 dip=48 slip=124Fault plane: strike=107 dip=52 slip=58Eigenvector: eigenvalue: 1.55 plunge: 65 azimuth: 314(T)Eigenvector: eigenvalue: -0.47 plunge: 25 azimuth: 128(N)Eigenvector: eigenvalue: -1.08 plunge: 2 azimuth: 219(P)Comments :The Harvard CMT solution is an overthrust, quite different from the P wave strikesllip solutionby Jones et al.

Station Azimuth Plunge C + D- 5 67 -52 47 -70 61 -92 43 -100 41 -140 54 +144 57 +146 54 +152 44 +158 61 -165 45 +180 45 +206 69 +226 44 +230 49 -230 52 -234 50 -237 50 +237 75 +245 75 -259 75 -289 69 +292 60 +291 68 +297 59 -297 61 -297 70 +300 54 +300 70 +303 61 -303 69 +310 42 -314 64 +316 64 +316 56 +318 68 +321 60 +321 67 +321 68 +328 69 +334 40 -336 67 +339 45 +340 68 +

77

Doubtful Bay, 6th February 1988Date :1988 February 06Place :Doubtful Bay, north Western Australia, Charnley 1:250000 Map.Surface expression :NilSolution Reference :Harvard University Seismology GroupType of analysis :Centroid Moment Tensor

Zoback Rating:C Fault Plane Rating:3020688B WESTERN AUSTRALIA Date (y/m/d): 1988/2/6Information on data used in inversion Wave nsta nrec cutoffBody 10 19 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 5 23 58.10 -16.70 124.64 10.0 5.2 0.0CMT 5 24 3.70 -16.13 124.85 15.0Error 2.20 0.21 0.15 0.0Assumed half duration: 1.5Mechanism information Exponent for moment tensor: 23 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 0.260 3.150 -3.410 0.500 -2.880 3.560Error 0.550 0.440 0.820 1.990 1.560 0.490Mw = 5.1 Scalar Moment = 5.53e+23Fault plane: strike=288 dip=66 slip=-10Fault plane: strike=22 dip=81 slip=-155Eigenvector: eigenvalue: 4.84 plunge: 11 azimuth: 153(T)Eigenvector: eigenvalue: 1.38 plunge: 64 azimuth: 41(N)Eigenvector: eigenvalue: -6.22 plunge: 23 azimuth: 248(P)Comments :The CMT solution is strikeslip with a component of normal faulting. The Taxis is horizontal,the P axis plunges at 64°.

Solution Reference :McCue and Paull(1991) – Alternative (Ripper)Hypocentre source :AGSOType of analysis :P wave polarities, Schmidt projection.Magnitudes :mb 5.2 ML 5.7Origin time (UTC) :052358.0Hypocentre, Latitude:-16.18 Longitude:124.51 Depth(km):05Mechanism :Normal faultNodal plane 1, Strike:143 Dip:46 Slip: Pole, Azimuth:053 Plunge:44Nodal plane 2, Strike:012 Dip:66 Slip: Pole, Azimuth:282 Plunge:34T axis Azimuth:080 Plunge:06N axis Azimuth:173 Plunge:27 Uncertainty:tight, anomalous station.P axis Azimuth:340 Plunge:64

Zoback Rating:X Fault Plane Rating:XComments :The prefered solutio is the Harvard CMT solution of the earthquake, a strikeslip solution. Thestation polarities number only nine, and a normal fault solution with only one anomalous station is possible. The Harvardsolution should be adopted.Parameters of the alternative normal fault solution with one anomalous station reading are shown below. One nodal plane isdrawn as close as possible to the anomalous dilatation.

78

Station Azimuth Plunge C + D- 103 45 -110 54 +132 42 +141 49 +202 43 -206 42 +209 42 +232 44 +

79

Bunnaloo, 3rd July 1988Date :1988 July 03Place :Bunnaloo, south NSW, Denilquin 1:250000 MapSurface expression :Nil

Solution Reference :McCue and Paull(1991)Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 4.0Origin time (UTC) :082312Hypocentre, Latitude:-35.73 Longitude:144.49 Depth(km):10Mechanism :StrikeslipNodal plane 1, Strike:254 Dip:76 Slip: -159 Pole, Azimuth:164 Plunge:14Nodal plane 2, Strike:160 Dip:70 Slip:-17 Pole, Azimuth:070 Plunge:20T axis Azimuth:026 Plunge:06N axis Azimuth:286 Plunge:75 Uncertainty:~30*20P axis Azimuth:118 Plunge:22 Zoback Rating:C Fault Plane Rating:4Comments :The solution as shown has the nodal plane dipping NNW passing to the north of two anomalousstation compressions. An alternative solution would pass the nodal plane south of these stations, making a single stationdilatation anomalous. Either way, the solution does not change much. The N axis uncertainty incorporates bothpossibilities.The T axis is horizontal. The P axis plunges at about 22° to the southeast.

Station Azimuth Plunge C + D- 16 46 +66 45 -73 45 +80 44 +84 47 -85 43 -88 45 -90 42 -140 40 -143.8 36 -144 40 -223 38 +231 5 +276 45 -318 40 -327 47 +

80

Uluru, 28 May 1989Date :1989 May 28Place :Uluru (Ayers Rock), south Northern Territory, central Australia, Ayers Rock 1:250000 Map.Surface expression :Nil

Solution Reference :Michael-Leiba et al.(1994).Hypocentre source :AGSOType of analysis :P wave polarity.Magnitudes :mb 5.4, MS 5.1,ML 5.6.Origin time (UTC) :025520.6Hypocentre, Latitude:-25.25 Longitude:130.65 Depth(km):31Mechanism :OverthrustNodal plane 1, Strike:324 Dip:50 Slip:76 Pole, Azimuth:234 Plunge:40Nodal plane 2, Strike:165 Dip:42 Slip: 106 Pole, Azimuth:075 Plunge:48T axis Azimuth:154 Plunge:79N axis Azimuth:333 Plunge:11 Uncertainty:Tight, with anomalous station polarities.P axis Azimuth:064 Plunge:02 Zoback Rating:C Fault Plane Rating:2Comments :The overthrust solution is tight with anomalous station dilatations within the P wavecompressional quadrant. While holding the solution orthogonal, the anomalous station dilatations are brought as close aspossible to the nodal planes.The P axis is horizontal and has an ENE orientation. No aftershocks were recorded to help identify the fault plane.

Station Azimuth Plunge C + D- 25 48 +38 44 -64 43 -68 44 -75 37 -102 38 +111 38 +120 38 +126 37 +127 42 -142 33 +146 43 +202 58 +231 38 +232 42 +235 44 -238 43 +241 45 +245 1 -249 43 +254 38 -260 43 +289 44 -316 56 +317 58 +321 59 +330 47 +347 46 +354 47 -

81

Beagle Bay, 13th October 1989Date :1989 October 13Place :North Western Australia, Pender 1:250000 Map.Surface expression :Nil


Zoback Rating:C Fault Plane Rating:3101389A WESTERN AUSTRALIA Date (y/m/d): 1989/10/13Information on data used in inversion Wave nsta nrec cutoffBody 14 31 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 9 59 11.80 -17.62 122.39 10.0 5.6 4.5CMT 9 59 25.80 -16.94 122.57 15.0Error 1.40 0.09 0.06 0.0Assumed half duration: 2.1Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT -0.570 1.740 -1.170 -0.330 -0.890 1.080Error 0.100 0.070 0.160 0.370 0.250 0.080Mw = 5.5 Scalar Moment = 2.09e+24Fault plane: strike=294 dip=59 slip=-13Fault plane: strike=31 dip=79 slip=-149Eigenvector: eigenvalue: 2.23 plunge: 13 azimuth: 159(T)Eigenvector: eigenvalue: -0.27 plunge: 57 azimuth: 49(N)Eigenvector: eigenvalue: -1.95 plunge: 30 azimuth: 257(P)Comments :The solution is strikeslip with a component of normal faulting; the P axis plunges at 30° andshould not be used as evidence for compressive stress.

82

Newcastle, 28th December 1989Date :1989 December 27(UTC); 28 December local time.Place :Newcastle,east NSW, Newcastle 1:250000 Map.Surface expression :Nil

Solution Reference :McCue et al.(1990).Hypocentre source :McCue et al.(1990).Type of analysis :P wave polarity, Schmidt projection.Magnitudes :mb 5.7, ML 5.6Origin time (UTC) :232658Hypocentre, Latitude:-32.95 Longitude:151.61 Depth(km):11.5Mechanism :OverthrustNodal plane 1, Strike:104 Dip:32 Slip:35 Pole, Azimuth:014 Plunge:58Nodal plane 2, Strike:339 Dip:65 Slip: 113 Pole, Azimuth:249 Plunge:25T axis Azimuth:274 Plunge:64N axis Azimuth:140 Plunge:20 Uncertainty:~55°*10°.P axis Azimuth:044 Plunge:17 Zoback Rating:E Fault Plane Rating:5Comments :The overthrust solution is constrained to have the southwest striking nodal plane pass throughRIV, which recorded a short period compression and long period dilatation, and to pass as close as possible to three SouthAustralian dilatations which are anomalous in a region of compressions whatever the solution. But from an overthrustsolution with almost horizontal P axis, the other nodal plane can dip through vertical, producing a mainly normal faultsolution with P axis plunging at about 45°.The fault plane solution is not necessarily indicative of a horizontal compressive stress.

Station Azimuth Plunge C + D- 6 38 -10 41 -93 12 -201 49 +201 30 +212 38 +213 29 +218 39 +219 31 +220 39 +222 38 +229 37 +236 29 +236.5 37 +236 41 +242 37 +260 49 -265 47 -273 40 -273 43 +277 43 +284 38 +294 53 +302 54 +308 76 +310 57 +318 39 +339 39 +

83

Meckering, 17th January 1990Date :1990 January 17Surface expression : NilPlace :Meckering, southeast Western Australia. Perth and Kellerberrin 1:250000 Maps

Solution Reference :McCue and Gregson(1993).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 5.5Origin time (UTC) :063808Hypocentre, Latitude:-31.70 Longitude:117.00 Depth(km):06Mechanism :Overthrust or strikeslipNodal plane 1, Strike:347 Dip:66 Slip:75 Pole, Azimuth:257 Plunge:24Nodal plane 2, Strike:200 Dip:28 Slip:120 Pole, Azimuth:110 Plunge:62T axis Azimuth:228 Plunge:65N axis Azimuth:353 Plunge:13 Uncertainty:Several solutions possibleP axis Azimuth:090 Plunge:18 Zoback Rating:X Fault Plane Rating:XComments :The solution has several anomalous station polarities, including the group of Chinese stations.Other solutions are possible which include the Chinese stations, but which are just as uncertain as they also include severalanomalous stations.

Station Azimuth Plunge C + D- 10 68 -13 45 +16 43 -38 42 -56 42 -63 5 -65 43 -71 57 -77 43 +88 65 +88.5 58 -89 45 -95 47 -96 48 +97 46 -99 48 +103 61 +108 60 +109 55 -111 57 -166 7 +175 67 +178 44 +204 64 +261 9 -314 68 +340 43 +342 69.5 +347 58 -347 67 -351 7 -353 67 -353 68 -

84

Woods Reef, 14th November 1990Date :1990 November 14Place :Woods Reef, northeast NSW, Manilla 1:250000 Map.Surface expression :Nil

Solution Reference :Bock(1993).Hypocentre source :AGSOType of analysis :Seismic phase amplitude ratios, Schmidt projection.Magnitudes :Ml 3.1Origin time (UTC) :185645Hypocentre, Latitude:-30.33 Longitude:150.84 Depth(km):06Mechanism :StrikeslipNodal plane 1, Strike:210 Dip:78 Slip: 161 Pole, Azimuth:120 Plunge:12Nodal plane 2, Strike:304 Dip:69 Slip: 11 Pole, Azimuth:214 Plunge:21T axis Azimuth:165 Plunge:24N axis Azimuth:002 Plunge:65 Uncertainty:UndefinedP axis Azimuth:258 Plunge:06 Zoback Rating:D Fault Plane Rating:5Comments :The method compares seismic phase amplitudes (Pn etc) of regional seismic stationseismograms with synthetic seismograms and minimises the differences. A unique solution was obtained in that the twonodal planes were recognised. N axis uncertainty was not given, but the given uncertainties of the orientations of the nodalplanes and P and T axes were not small. The 6° plunge of the P axis can vary from -16° to 32°, thus not necessarily close tohorizontal, and the 24° plunge of the T axis from 1° to 44°. Station BRS P wave compression was anomalous to theamplitude ratio solution, but close to a nodal plane.

Station Azimuth Plunge C + D- BRS 31 46 +JNL 190 45 +CMS 255 44 -NEWH 279 3 -

85

Bajool, 10th June 1991Date :1991 June 10Place :Bajool, east Queensland, Rockhamton 1:250000 Map.Surface expression :Nil.

Solution Reference :McKavanagh et al.(1993).Hypocentre source :McKavanagh et al.(1993).Type of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 2.9Origin time (UTC) :120023Hypocentre, Latitude:-23.60 Longitude:150.63 Depth(km):10Mechanism :UndefinedNodal plane 1, Strike:130 Dip:40 Slip: 90 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 310 Dip:50 Slip: 90 Pole, Azimuth: Plunge:T axis Azimuth: 220 Plunge:84N axis Azimuth: Plunge: Uncertainty:Very large.P axis Azimuth:40 Plunge:6 Zoback Rating:X Fault Plane Rating:XComments :The six station polarities allow almost any solution to be plotted. McKavanagh et al. state that aunique source mechanism for the main shock could not be obtained---- (but) the number of possibilities is reduced if theknown structural geology and the inferred principal stress direction are used as constraints.In other words, the inferred principal tectonic stress direction is used to obtain the fault plane solution and the P axisorientation, hence the fault plane solution should not be used as evidence for a compressional stress field of any orientation.

Station Azimuth Plunge C + D- MTMQ 52 13 -AWD 123 32 +UCQ 158 22 -BDM 156 40 +CRC 189 46 +BJLQ 317 4 -

86

Tennant Creek 19th June 1991Date :1991 June 19Place :Tennant Creek, Northern Territory, Tennant Creek 1:250000 Map.Surface expression :Nil.

Solution Reference :McCue and Gregson(1994).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :mb 5.2, ML 5.1.Origin time (UTC) :113824.7Hypocentre, Latitude:-19.79 Longitude:133.95 Depth(km):03Mechanism :Normal fault.Nodal plane 1, Strike:226 Dip:34 Slip:-131 Pole, Azimuth:136 Plunge:56Nodal plane 2, Strike:092 Dip:64 Slip: -66 Pole, Azimuth:002 Plunge:26T axis Azimuth:186 Plunge:20N axis Azimuth:260 Plunge:20 Uncertainty:~30°*5°.P axis Azimuth:006 Plunge:70 Zoback Rating:C Fault Plane Rating:3Comments :The solution is reasonably good and tight apart from two anomalous compressions in the centraldilatational quadrant, which have been ignored. The P axis is virtually vertical.

Station Azimuth Plunge C + D- 4 69 +92 50 +96 44 -116 49 -140 50 +152 50 +180 46 +180 72 -224 50 +228 50 +243 54 +266 5 -255 51 -269 5 -273 5 +276 5 +279 5 +281 5 +284 5 +285 5 +287 5 +289 5 +290 5 +295 70 -310 51 -316 67 -338 50 -

87

Tennant Creek, 8th July 1991Date :1991 July 08Place :Tennant Creek, Northern Territory, Tennant Creek 1:250000 Map.Surface expression :Nil

Solution Reference :McCue and Gregson(1994).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection.Magnitudes :mb 5.1, ML 5.0Origin time (UTC) :104534.2Hypocentre, Latitude:-19.861 Longitude:133.866 Depth(km):05Mechanism :Normal fault.Nodal plane 1, Strike:238 Dip:48 Slip: -136 Pole, Azimuth:148 Plunge:42Nodal plane 2, Strike:115 Dip:57 Slip: -50 Pole, Azimuth:025 Plunge:33T axis Azimuth:177 Plunge:03N axis Azimuth:270 Plunge:34 Uncertainty:Tight, non-orthogonal.P axis Azimuth:080 Plunge:60 Zoback Rating:C Fault Plane Rating:3Comments :To attempt to get an orthogonal solution, the nodal plane dipping northwest is held close to theWRA array stations and to two station dilatations in the northwest quadrant of the projection.. The other nodal plane ispulled close to the compressions and dilatation in the southwest quadrant of the projection, the dilatation being anomalous.As such, the solution is tight with the anomalous dilatation close to the nodal plane. However, there are three anomalousstation compressions in the centre of the solution which are anomalous and ignored, placing some doubt on the solution.The P axis is not horizontal. McCue and Gregson postulate settlement of the block upthrown by the 1988 Tennant Creekwestern Lake Surprise Fault "mainshocks" as the mechanism of this and the 19 June 1991 earthquakes.

Station Azimuth Plunge C + D- 94 50 -106 50 +130.5 51 -151 50 -160 50 -179 41 +184 70 -205 49 -227 48 +241 47 +244 3 -246 3 -249 3 -251 3 -252.5 3 -255 3 -257 3 -259 3 -281 3 -320 49 -328 68 +334 72 +338 50 -

88

Moralana, February 1992Date :1992, February.Place :Moralana, east South Australia, Parachilna 1:250000 Map.Surface expression :NilSolution Reference :Greenhalgh et al.(1994), and Michael-Leiba and Dent(1994). The earthquake swarm began inNovember 1991 and lasted through February 1992. Flinders University of South Australia carried out a micro-earthquakesurvey at Moralana during 6-23 February, and the eight best-located earthquakes were used to construct a fault-planecomposite , assuming all earthquakes occurred on the same plane.The composite is an overthrust striking northeast-southwest, with the fault plane dipping either northwest or southeast.

Station Azimuth Plunge C + D- 4.3 50 +52 53 +72 47 +78 87 +82 28 -92 50 +99 42 +102 22 -105 34 -105 49 +107 60 +113 23 -116 47 -119 18 -120 44 -130 18 -134 29 -134 32 -141 58 +141 24 -142 34 +142 48 +144 34 -147 34 -149 36 -151 39 -155 43 +158 57 +161 32 -161 39 -173 22 -175 29 -176 23 -181 24 -181 33 -188 24 -195 28 -195 43 +199 20 -199 44 +205 25 +205 46 +208 42 +211 81 +214 28 -214 54 +227 24 +229 24 +231 24 +245 27 -245 32 -256 28 -259 31 -264 22 -264 60 +

89

279 32 -283 72 +292 30 -296 67 +302 48 -318 48 -332 77 +352 45 +352 48 +

90

Ellalong, 6th August 1994Date :1994 August 06Place :Ellalong, east NSW, Singleton 1:250000 Map.Surface expression :Nil

Solution Reference :Jones et al.(1995), McCue and Gregson(1996).Hypocentre source :AGSOType of analysis :P wave Polarity, Schmidt projection.Magnitudes :mb 5.3, ML 5.3.Origin time (UTC) :110351.6Hypocentre, Latitude:-32.924 Longitude:151.288 Depth(km):02Mechanism :Overthrust.Nodal plane 1, Strike:309 Dip:44 Slip:77 Pole, Azimuth:219 Plunge:46Nodal plane 2, Strike:147 Dip:48 Slip:102 Pole, Azimuth:057 Plunge:42T axis Azimuth:100 Plunge:79N axis Azimuth:319 Plunge:09 Uncertainty:Tight, non-orthogonal, anomalous stations.P axis Azimuth:230 Plunge:03 Zoback Rating:C Fault Plane Rating:3Comments :The nodal plane dipping southwest is tightly constrained, but on the basis of an emergentdilatation at station STKA. The other nodal plane orientation can vary slightly depending on which stations are ignored andare anomalous, or accepted. The adopted nodal plane orientation attempts to average these uncertainties.The P axis is horizintal on a southwest azimuth.

Station Azimuth Plunge C + D- ARMA 7 40 +BRS 13 40 -CHI 27 38 -NLD 85 38 -NPS 91 38 +KIM 93 38 +MHL 181 49 +RIV 186 42 +MOO 196 42 -CNB 215 40 -TOO 224 39 -BFD 237 40 -WRG 275 42 +STKA 276 40 -CMS 283 40 +ASPA 297 46 +QLP 314 40 +RMQ 334 38 +CTAO 340 42 -

91

Southern Ocean, 15th May 1995Date :1995 May 15Place :Southern Ocean, south of Western Australia, west of Tasmania.Surface expression :Nil.


Zoback Rating:C Fault Plane Rating:3051595I SOUTH OF AUSTRALIA Date (y/m/d): 1995/5/15Information on data used in inversion Wave nsta nrec cutoffBody 47 79 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 22 29 31.30 -42.38 120.04 10.0 5.3 4.9CMT 22 29 37.10 -42.52 120.51 15.0Error 0.20 0.03 0.05 0.0Assumed half duration: 1.3Mechanism information Exponent for moment tensor: 24 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 1.200 -1.120 -0.090 -0.860 -0.220 0.160Error 0.030 0.030 0.040 0.150 0.090 0.030Mw = 5.4 Scalar Moment = 1.46e+24Fault plane: strike=109 dip=28 slip=111Fault plane: strike=266 dip=64 slip=79Eigenvector: eigenvalue: 1.53 plunge: 70 azimuth: 154(T)Eigenvector: eigenvalue: -0.12 plunge: 10 azimuth: 271(N)Eigenvector: eigenvalue: -1.40 plunge: 18 azimuth: 4(P)Comments :The CMT solution is an overthrust with north-south P axis, suggesting north-southcompression.McCue and Gregson(1997) attempted a P wave polarity solution, but their best solution, an overthrust similar to , but notidentical with, the CMT solution, still had significant anomalous station polarities, and they preferred the CMT solution.

92

White Cliffs, 13th August 1996Date :1996 August 13Place :The Range, White Cliffs, west NSW, White Cliffs 1:250000 Map.Surface expression :Nil.

Solution Reference :McCue et al.(1996).Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projection, aftershock locations.Magnitudes :mb 4.9, ML 5.1.Origin time (UTC) :043010.7Hypocentre, Latitude:-30.08 Longitude:143.52 Depth(km):02Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:213 Dip:64 Slip: -136 Pole, Azimuth:123 Plunge:26Nodal plane 2, Strike:100 Dip:52 Slip:-35 Pole, Azimuth:010 Plunge:38T axis Azimuth:335 Plunge:07N axis Azimuth:238 Plunge:42 Uncertainty:Tight, non-orthogonal.P axis Azimuth:072 Plunge:50 Zoback Rating:C Fault Plane Rating:2Comments :Apart from one anomalous station compression (ARMA) which is ignored, the solution is tightwith two station dilatations close to but on the wrong side of a nodal plane. McCue et al. drew in a second possible solution(dashed lines), but this solution has station dilatation Buckleboo (BBOO) anomalously positioned in a compressionalquadrant. This solution was not preferred.McCue stated that the aftershocks are oriented NNE (Gibson pers comm) so that the nodal plane striking NNE-SSW is thelikely fault plane.

Station Azimuth Plunge C + D- QLP 10 47 -AMO 54 46 -BRS 77 45 -

93 22 -CMSA 128 44 -CNB 153 43 -

159 42 -TOO 169 45 +

172 47 +188 42 +198 62 -200 43 +218 42 +218 41 +227 43 +237 43 +246 43 +259 47 +263 43 +303 46 +303 54 +317 47 +327 55 +338 44 +

93

Thomson Dam, 25th September 1996Date :1996 September 25Place :Under Thomson Dam, Gippsland, Vic..Surface expression :Nil.

Solution Reference :Allen T. Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :mb 4.7, ML 5.0.Origin time (UTC) :074957.0Hypocentre, Latitude:-37.88 Longitude:146.43 Depth(km):11Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:76 Dip:64 Slip: 124 Pole, Azimuth:166 Plunge:26Nodal plane 2, Strike:199 Dip:41 Slip: 41 Pole, Azimuth:289 Plunge:49T axis Azimuth:143 Plunge:13N axis Azimuth:238 Plunge:42 Uncertainty:Tight.P axis Azimuth:034 Plunge:56 Zoback Rating:C Fault Plane Rating:2Comments :Thirty stations with only few anomalous stations.

Station Azimuth Plunge C+ D-FSH 21 5 +LGT 38 30 +IVJS 18 48 +DRA 21 49 +DDC 32 50 +MIT 34 50 +JBRS 40 50 +WERS 42 50 +NAR 41 50 +IVS 16 50 +DTMS 33 50 +CDN 86 7 -ROY 104 6 -RORS 104 6 -MCV 113 16 -TMA 128 75 -TOM 129 58 -TOS 150 70 -TOSS 150 70 -ABE 170 43 -DVBX 249 31 -GLB 264 51 +SHY 273 31 -MPD 278 31 -SHY 283 31 -CRN 298 50 +WSK 298 50 -HOP 313 50 +KOWA 324 50 -TYR 359 28 -

94

Burra, 5th March 1997Date :1997 March 05Place :Burra, southeast South Australia, Burra 1:250000 Map.Surface expression :Nil

Solution Reference :Mountford et al. (1997). Hypocentre source :Mountford et al.(1997).Type of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 5.1Origin time (UTC) :061521Hypocentre, Latitude:-33.816 Longitude:138.984 Depth(km):20.4Mechanism :OverthrustNodal plane 1, Strike:025 Dip:40 Slip: 112 Pole, Azimuth:295 Plunge:50Nodal plane 2, Strike:177 Dip:52 Slip: 72 Pole, Azimuth:087 Plunge:38T axis Azimuth:035 Plunge:76N axis Azimuth:187 Plunge:12 Uncertainty:Tight, 1°*1°.P axis Azimuth:280 Plunge:05 Zoback Rating:B Fault Plane Rating:1Comments :Except for one anomalous station dilatation within the central P wave compressional quadrant,the solution is a tight overthrust with horizontal P axis.

Station Azimuth Plunge C + D- 6 39 +11 9 +11 13 +48 38 -70 38 +93 39 +94.5 39 +110 39 -122 26 +130 39 -131 11 -133 39 +138 39 +140 39 +141 39 +155 39 +158 39 +162 39 +215 39 +272 39 -288 38 -301 38 -308 38 -320.5 39 +338 39 +348 15 +

Solution Reference :McCue, et al. (2001). Type of analysis :P wave polarity, Schmidt projection.Magnitudes :ML 5.1Origin time (UTC) :061521Hypocentre, Latitude:-33.816 Longitude:138.984 Depth(km):20.4Mechanism :OverthrustNodal plane 1, Strike:218 Dip:70 Slip: 114 Pole, Azimuth:128 Plunge:20Nodal plane 2, Strike:346 Dip:30 Slip: 42 Pole, Azimuth:256 Plunge:60T axis Azimuth:158 Plunge:36N axis Azimuth:029 Plunge:22 Uncertainty:Well constrained 5°*5°.P axis Azimuth:290 Plunge:26 Zoback Rating:B Fault Plane Rating:2Comments :A few anomalous stations particularly around the east dipping axis. The solution is a tightoverthrust with horizontal P axis.

95

Station Azimuth Plunge C+ D-ADT 12 13 +THS 15 14 +QLP 43 42 +STRR 55 33 -RMQ 54 34 -CMSA 72 29 +ARMA 78 31 +YRR 92 33 +YCR 93 31 +YOU 95 30 +CNB 102 31 -CRN 130 44 -GOG 133 38 -BFD 135 37 -GRX 145 51 +WRA 148 55 +GIRL 285 49 -BBOO 291 30 -WARB 298 30 -RPA 305 25 -ASAR 324 50 -KAKA 310 33 -PNA 331 43 +WB2 327 58 -

96

Collier Bay, 10th August 1997Date :1997 August 10Place :Collier Bay, northwest coast of Western Australia, Camden Sound/Yampi 1:250000 Maps.Surface expression :Nil.


Zoback Rating:C Fault Plane Rating:3081097A NORTHWEST WESTERN AUSTRALIA Date (y/m/d): 1997/8/10Information on data used in inversion Wave nsta nrec cutoffBody 54 121 45Mantle 49 93 135Timing and location information hr min sec lat lon depth mb MsPDE 9 20 31.00 -16.01 124.33 10.0 5.9 6.0CMT 9 20 38.00 -15.98 124.48 15.0Error 0.10 0.01 0.01 0.0Assumed half duration: 3.0Mechanism information Exponent for moment tensor: 25 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT 0.330 1.390 -1.720 -1.210 -0.910 1.380Error 0.020 0.010 0.020 0.060 0.060 0.010Mw = 6.2 Scalar Moment = 2.56e+25Fault plane: strike=299 dip=60 slip=15Fault plane: strike=201 dip=77 slip=149Eigenvector: eigenvalue: 2.79 plunge: 31 azimuth: 156(T)Eigenvector: eigenvalue: -0.46 plunge: 57 azimuth: 0(N)Eigenvector: eigenvalue: -2.33 plunge: 11 azimuth: 253(P)Comments :The solution is essentially strikeslip with some overthrust.

\Station Azimuth Plunge C+ D-KAKA 69 29 -WB2 103 29 +QIS 110 30 +CMSA 131 35 +STAK 135 34 +BBOO 151 32 -FORT 169 31 +SPA 181 70 +WOOL 188 31 +ASPA 131 31 -BAL 199 31 +KLB 202 31 +GIRL 230 29 +GRM 236 68 -RSR 236 71 -ALF 244 68 -SCR 244 71 -

306 60 -DNP 306 29 -

97

Tennant Creek 15th April 1999

Date :1999 April 15Place :Tennant CreekSurface expression :Nil

Solution Reference :This reportHypocentre source :GAType of analysis P wave polarity, Schmidt projection:Magnitudes :5.1Origin time (UTC) :4:55:53Hypocentre, Latitude: -19.79 Longitude: 134.04 Depth(km): 5Mechanism : ThrustNodal plane 1, Strike: 285 Dip: 68 Slip: 15 Pole, Azimuth: 195 Plunge: 22Nodal plane 2, Strike: 22 Dip: 60 Slip: 112 Pole, Azimuth: 112 Plunge: 30T axis Azimuth: 242 Plunge: 36N axis Azimuth: 70 Plunge: 52 Uncertainty: TightP axis Azimuth: 336 Plunge: 3 Zoback Rating: C Fault Plane Rating: 1Comments :

Station Azimuth Plunge C+ D-QIS 97 43 -ARMA 127 50 -QLP 128 43 -YOU 141 53 -STKA 152 45 -BFD 159 49 -ASPA 181 43 +CSY 192 66 +FORT 204 45 +WB0 269 11 +WB9 273 11 +WB8 276 11 +WB7 280 11 +WB6 284 11 +WB5 288 11 +WB4 292 11 -WB3 295 11 -WB2 297 11 -WB1 299 11 -WR1 298 11 -WR2 297 11 -WR3 296 11 -KAKA 346 40 -

98

Boolarra South, 29th August 2000Date :2000 August 29Place :Boolara South, Victoria.Surface expression :Nil.

Solution Reference :Allen T.Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 5.0.Origin time (UTC) :120552.4Hypocentre, Latitude:-38.42 Longitude:146.29 Depth(km):18Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:216 Dip:67 Slip: 68 Pole, Azimuth:123 Plunge:26Nodal plane 2, Strike:082 Dip:32 Slip: 49 Pole, Azimuth:010 Plunge:38T axis Azimuth:092 Plunge:60N axis Azimuth:226 Plunge:30 Uncertainty: 5°*25°.P axis Azimuth:326 Plunge:20 Zoback Rating:D Fault Plane Rating:3Comments :Southwest – northeast striking plane well constrained.

Station Azimuth Plunge C+ D-FSHM 28 26 -DTMM 26 50 +SGTH 48 30 +TOMM 187 19 -WILL 262 27 -ROWM 296 50 -SBSV 308 76 +CCRM 294 50 -MACM 293 49 -BUCM 292 50 -CDMM 306 30 -RUSM 320 50 -MLWM 330 50 -ROYM 314 30 -KOWM 332 50 -

99

Exmouth Plateau, 11th October 2000Date :2000 October 11Place :Off coast of northwest Australia, near Barrow Island.Surface expression :Nil.


Zoback Rating:C Fault Plane Rating:3101100D NORTHWEST OF AUSTRALIA Date (y/m/d): 2000/10/11Information on data used in inversion Wave nsta nrec cutoffBody 12 17 45Mantle 0 20 0Timing and location information hr min sec lat lon depth mb MsPDE 19 27 13.30 -20.07 112.90 10.0 5.3 4.4CMT 19 27 15.00 -20.07 112.90 15.0Error 2.00 0.00 0.00 0.0Assumed half duration: 1.0Mechanism information Exponent for moment tensor: 23 units: dyne/cm Mrr Mtt Mpp Mrt Mrp MtpCMT -0.120 3.340 -3.230 1.580 2.220 -2.450Error 0.630 0.380 0.890 2.130 1.760 0.560Mw = 5.1 Scalar Moment = 4.84e+23Fault plane: strike=150 dip=62 slip=-10Fault plane: strike=245 dip=81 slip=-152Eigenvector: eigenvalue: 4.33 plunge: 12 azimuth: 14(T)Eigenvector: eigenvalue: 1.02 plunge: 61 azimuth: 261(N)Eigenvector: eigenvalue: -5.35 plunge: 26 azimuth: 111(P)Comments :The solution is essentially strikeslip with some normal fault.

100

Dumbalk, 30th October 2000Date :2000 October 30Place :Dumbalk, Victoria.Surface expression :Nil.

Solution Reference :Allen T.Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 3.2Origin time (UTC) :173034.3Hypocentre, Latitude:-38.56 Longitude:146.05 Depth(km):16Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:238 Dip:42 Slip: 72 Pole, Azimuth:328 Plunge:48Nodal plane 2, Strike:082 Dip:51 Slip: 74 Pole, Azimuth:172 Plunge:39T axis Azimuth:052 Plunge:76N axis Azimuth:251 Plunge:12 Uncertainty: 5°*10°.P axis Azimuth:161 Plunge:05 Zoback Rating:D Fault Plane Rating:3Comments :Northwest dipping plane well constrained.

Station Azimuth Plunge C+ D-TOM 18 31 -FSH 8 44 -SGTH 56 54 +SKRN 116 45 -SBCH 198 56 -MDR 209 19 -JEN 233 28 -SBSV 235 38 -WILL 247 17 -SYRM 267 23 -HEX 284 50 +ROW 300 49 -CCR 308 50 -MAC 310 50 -CDN 312 30 -MLW 342 50 - ROY 326 30 -

101

Boolarra South, 4th July 2001Date :2001 July 4Place :Boolara South, Victoria.Surface expression :Nil.

Solution Reference :Allen T.Hypocentre source :AGSOType of analysis :P wave polarity, Schmidt projectionMagnitudes :ML 3.4.Origin time (UTC) :041642.3Hypocentre, Latitude:-38.47 Longitude:146.34 Depth(km):7Mechanism :Normal fault with strikeslip.Nodal plane 1, Strike:179 Dip:62 Slip: 66 Pole, Azimuth:269 Plunge:28Nodal plane 2, Strike:042 Dip:35 Slip: 34 Pole, Azimuth:132 Plunge:55T axis Azimuth:050 Plunge:66N axis Azimuth:189 Plunge:20 Uncertainty: 5°*30°.P axis Azimuth:286 Plunge:14 Zoback Rating:D Fault Plane Rating:4Comments :South striking plane well constrained.

Station Azimuth Plunge C+ D-FSH 37 3 +DTMM 28 52 +THOP 147 4 -TOM 183 3 +SBSV 187 81 +SYRM 295 1 -MAC 303 51 -MLW 334 32 -

102

Burakin, September 28th 2001Date : 28/09/2001Place : BurakinSurface expression : none

Solution Reference : This report Angela Bullock/Mark LeonardHypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 5.1Origin time (UTC) : 0254 UTHypocentre, Latitude: -30.493 Longitude: 117.058 Depth(km): 0.06Mechanism : strike-slipNodal plane 1, Strike: 102.8 Dip: 83.7 Slip: 31.4 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 8.9 Dip: 58.8 Slip: 172.6 Pole, Azimuth: Plunge:T axis Azimuth: 330 Plunge: 26N axis Azimuth: 113 Plunge: 58 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 231 Plunge: 17 Zoback Rating: B Fault Plane Rating: 3Comments : 20 stations Station MEEK does not fit solution

Station Azimuth Plunge C+ D-CMC 173 0.7 + BLDU 248 0.6 -KLBR 151 -30.8 +MUN 205 -42.2 -MORW 327 -42.2 +MEEK 19 -42.2 -RKGY 180 -42.2 -GIRL 341 -42.2 eKMBL 103 -42.2 eFITZ 34 -42.2 +FORT 94 -42.2 eBBOO 103 -42.2 -ASPA 69 -42.2 eKNA 38 -42.2 eSTKA 100 -55.3 eARPS 113 -56.2 +KAKA 41 -57.4 +QLP 87 -57.9 -CMSA 99 -57.9 -RMQ 89 -60.1 +

103

Ravensthorpe, October 19th 2001Date : 19/10/2001Place : RavensthorpeSurface expression : none

Solution Reference : Clark D.Hypocentre source : GAType of analysis : First motionMagnitudes : ML 5.2Origin time (UTC) : 1743 UTHypocentre, Latitude: -33.635 Longitude: 120.607 Depth(km): 19Mechanism : normalNodal plane 1, Strike: 264 Dip: 48 Slip: -90 Pole, Azimuth: 354 Plunge: 42Nodal plane 2, Strike: 084 Dip: 42 Slip: -90 Pole, Azimuth: 174 Plunge: 48T axis Azimuth: 354 Plunge: 3N axis Azimuth: 084 Plunge: 0 Uncertainty: <30deg in azimuth, 0deg in dipP axis Azimuth: 174 Plunge: 87 Zoback Rating: D Fault Plane Rating: 4Comments : 19 stations reasonably good fit Stations STKA and FITZ do not fit solution

Station Azimuth Plunge D+C-KMBL 25 42.2 +KLBR 309 42.2 -RKGY 251 42.2 -BLDU 311 42.2 -MORW 318 42.2 +FORT 67 42.2 -MEEK 345 42.2 +GIRL 331 42.2 +MUN 292 42.2 eBBOO 90 42.2 eASPA 52 42.2 -FITZ 17 42.2 -ARPS 106 42.2 -STKA 90 42.2 +CMSA 91 55.6 -QIS 56 55.4 -RMQ 81 58.7 -CSY 187 61.5 -MAW 206 64.4 -

104

Burakin December 25th 2001Date : 25/12/2001Place : BurakinSurface expression : none

Solution Reference : This report Angela Bullock/Mark LeonardHypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 4.0Origin time (UTC) : 0056 UTHypocentre, Latitude: -30.526 Longitude: 117.062 Depth(km): 1.52Mechanism : Over thrustNodal plane 1, Strike: 188.9 Dip: 83.0 Slip: 89.0 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 17.1 Dip: 7.1 Slip: 98.2 Pole, Azimuth: Plunge:T axis Azimuth: 98 Plunge: 52N axis Azimuth: 189 Plunge: 1 Uncertainty: <10deg in azimuth, <5 deg in dipP axis Azimuth: 280 Plunge: 38 Zoback Rating: B Fault Plane Rating: 3Comments : 15 stations Station MORW does not fit solution

Station Azimuth Plunge C+D-CMC 173 3.6 eBLDU 254 3.0 -PIG2 215 2.4 +GOK 192 1.1 +PIG3 212 1.0 -KLBR 151 -30.8 +PIG4 211 -30.8 -MORW 328 -42.2 +NWAO 176 -42.2 eRKGY 180 -42.2 eMEEK 19 -42.2 +KMBL 102 -42.2 +FORT 94 -42.2 -eGIRL 341 -42.2 eBK1 276 16.6 e

105

Burakin December 25th 2001Date : 28/12/2001Place : BurakinSurface expression : none

Solution Reference : This report Angela Bullock / Mark LeonardHypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 4.5Origin time (UTC) : 1631 UTHypocentre, Latitude: -30.539 Longitude: 117.063 Depth(km): 2.04Mechanism : overthrust Nodal plane 1, Strike: 195.6 Dip: 68.1 Slip: 84.6 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 29.7 Dip: 22.5 Slip: 103.2 Pole, Azimuth: Plunge:T axis Azimuth: 96 Plunge: 66N axis Azimuth: 197 Plunge: 5 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 298 Plunge: 23 Zoback Rating: B Fault Plane Rating: 3Comments : 20 stations Station MORW does not fit solution

Station Azimuth Plunge C+D-BK1 289 19.7 -BLDU 256 3.9 -PIG2 217 3.1 +GOK 192 1.4 ePIG3 212 1.3 +KLBR 150 -30.8 +PIG4 212 -30.8 -MUN 206 -42.2 +MORW 328 -42.2 +NWAO 176 -42.2 +RKGY 180 -42.2 eMEEK 19 -42.2 eKMBL 102 -42.2 +KAKA 41 -57.4 eGIRL 341 -42.2 eFORT 94 -42.2 eFITZ 34 -42.2 eBBOO 102 -42.2 eASPA 69 -42.2 eSTKA 100 -55.3 e

106

Burakin March 5th 2002Date : 05/03/2002Place : BurakinSurface expression : none

Solution Reference : This report Leonard, M. and Bullock, A.Hypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 5.0Origin time (UTC) : 0147 UTHypocentre, Latitude: -30.477 Longitude: 117.087 Depth(km): 0.26Mechanism : overthrustNodal plane 1, Strike: 223.0 Dip: 41.7 Slip: -109.7 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 68.7 Dip: 51.2 Slip: -73.2 Pole, Azimuth: Plunge:T axis Azimuth: 147 Plunge: 5N axis Azimuth: 238 Plunge: 13 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 37 Plunge: 76 Zoback Rating: B Fault Plane Rating: 3Comments : 20 stations Station FORT does not fit solution

Station Azimuth Plunge C+D-CA3 225 7.0 -BK1 241 3.6 -CMC 178 1.0 +BLDU 247 0.9 -KLBR 153 -30.8 +PIG4 211 -30.8 -MORW 326 -42.2 -MUN 206 -42.2 -NWAO 177 -42.2 eMEEK 19 -42.2 eRKGY 181 -42.2 +KMBL 103 -42.2 +FORT 94 -42.2 +FITZ 34 -42.2 -GIRL 341 -42.2 eBBOO 103 -42.2 -STKA 100 -55.3 -ARPS 113 -56.2 eKAKA 41 -57.4 -CMSA 99 -57.9 -

107


Solution Reference : This report Leonard, M. and Bullock, A.Hypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 4.6Origin time (UTC) : 0329 UTHypocentre, Latitude: -30.502 Longitude: 117.060 Depth(km): 0.44Mechanism : overthrust / strike-slipNodal plane 1, Strike: 263.8 Dip: 68.1 Slip:-59.60 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 26.23 Dip: 36.85 Slip: -141.52 Pole, Azimuth: Plunge:T axis Azimuth: 332 Plunge: 17N axis Azimuth: 71 Plunge: 28 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 213 Plunge: 56 Zoback Rating: B Fault Plane Rating: 3Comments : 18 stations Station KMBL does not fit solution

Station Azimuth Plunge C+D-BK1 251 7.1 -CMC 173 1.3 +BLDU 249 1.2 -KLBR 151 -30.8 +PIG4 211 0.2 -MUN 206 -42.2 -MORW 328 -42.2 +MEEK 19 -42.2 +RKGY 180 -42.2 eKMBL 103 -42.2 +NWAO 176 0.1 +GIRL 341 -42.2 eFORT 94 -42.2 eFITZ 34 -42.2 eSTKA 100 -42.2 -KAKA 41 -57.4 +BBOO 103 -42.2 -CMSA 99 -57.9 -

108

Burakin March 23rd 2002Date : 23/03/2002Place : BurakinSurface expression : none

Solution Reference : This report Leonard, M. and Bullock, A.Hypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 4.8Origin time (UTC) : 1316 UTHypocentre, Latitude: -30.522 Longitude: 117.076 Depth(km): 1.65Mechanism : overthrust / strike-slipNodal plane 1, Strike: 285.2 Dip: 79.3 Slip: -55.3 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 30.3 Dip: 36.1 Slip: -161.6 Pole, Azimuth: Plunge:T axis Azimuth: 349 Plunge: 26N axis Azimuth: 98 Plunge: 34 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 230 Plunge: 45 Zoback Rating: B Fault Plane Rating: 3Comments : 27 stations Stations GIRL,NWAO do not fit solution

Station Azimuth Plunge C+D-BK1 272 14.8 -CMC 176 3.8 +BLDU 254 3.1 -PIG2 216 2.5 -PIG3 212 1.0 -KLBR 151 -30.8 +PIG4 212 0.7 -MUN 206 -42.2 -MORW 327 -42.2 +NWAO 176 -42.2 +GIRL 341 -42.2 -KMBL 102 -42.2 +FORT 94 -42.2 eTOO 114 -57.9 eCTA 75 -60.1 eFITZ 34 -42.2 +BBOO 103 -42.2 -ASPA 69 -42.2 eSTKA 100 -55.3 -ARPS 113 -56.2 -QIS 69 -57.4 +KAKA 41 -57.4 +QLP 87 -57.9 +CMSA 99 -57.9 -RMQ 89 -60.1 -MEEK 19 -42.2 +CA3 296 34.0 +

109


Solution Reference : This report Leonard, M. and Bullock, A.Hypocentre source : GAType of analysis : single-event solutionMagnitudes : ML 5.2Origin time (UTC) : 2115 UTHypocentre, Latitude: -30.525 Longitude: 117.049 Depth(km): 1.22Mechanism : overthrustNodal plane 1, Strike: 27.0 Dip: 64.0 Slip: 90.0 Pole, Azimuth: Plunge:Nodal plane 2, Strike: 207.0 Dip: 26.0 Slip: 90.0 Pole, Azimuth: Plunge:T axis Azimuth: 297 Plunge: 71N axis Azimuth: 27 Plunge: 0 Uncertainty: <10 deg in azimuth, <5 deg in dipP axis Azimuth: 117 Plunge: 19 Zoback Rating: C Fault Plane Rating: 3Comments : 26 stations Stations BBOO,GIRL,NWAO,PIG4,QLP do not fit solution

Station Azimuth Plunge C+D-CA3 354 43.5 +BK4 41 11.6 +CMC 171 3.0 -PIG2 214 2.0 ePIG3 211 0.8 -KLBR 150 -30.8 -PIG4 211 0.5 +MUN 206 -42.2 +MORW 328 -42.2 +NWAO 176 -42.2 -MEEK 19 -42.2 eKMBL 102 -42.2 eGIRL 341 -42.2 -FORT 94 -42.2 eFITZ 34 -42.2 +ASPA 69 -42.2 eSTKA 100 -55.3 -QIS 69 -57.4 +KAKA 41 -57.4 eQLP 87 -57.9 +CMSA 99 -57.9 -RMQ 89 -60.1 -CTA 75 -60.1 eBBOO 102 -42.2 +BK1 277 17.3 eBK5 84 12.5 -

110

Sutton Swarm December 2001 – April 2002Date : 12/2001 - 4/2002Place : SuttonSurface expression : none

Solution Reference : Clark D. and Levinson M.Hypocentre source : GAType of analysis : First motion, 8 event composite solutionMagnitudes : ≤ ML 2.5Origin time (UTC) : variousHypocentre, Latitude: Longitude: Depth(km): Mechanism : thrustNodal plane 1, Strike: 82 Dip: 10 Slip: 79 Pole, Azimuth: 172 Plunge: 80Nodal plane 2, Strike: 273 Dip: 80 Slip: 92 Pole, Azimuth: 183 Plunge: 10T axis Azimuth: 185 Plunge: 55N axis Azimuth: 92 Plunge: 2 Uncertainty: 20-30deg in azimuth, <5deg in dipP axis Azimuth: 360 Plunge: 35 Zoback Rating: C Fault Plane Rating: 3Comments : 38 polarities plotted, three did not fit the best-fit solution

Station Azimuth Plunge C+D-MP3 267 65 +MP2 79 32.3 +CNB 153 14.4 -YNG 320 -23 -MILA 183 -37.9 eMGCD 37 -44.1 eMP3 276 57.5 +MP2 75 33.4 +CNB 154 14.2 eYNG 320 -23 eMP1 80 42.2 +MP4 302 33.5 +MP2 70 13.4 +CNB 155 5.4 -MP3 278 60 +MP2 75 32.1 +CNB 153 14.1 eYNG 320 -23 eMP1 81 25.1 -MP3 285 14.2 +MP2 71 7.7 +CNB 154 3.3 +MILA 183 -37.9 eMP1 33 12.6 +MP4 342 11 +MP3 325 9.3 -CNB 148 3.8 -MP5 185 71.8 +MP4 292 42.4 +GMP1 98 38.6 +GMP3 273 27.1 +GCNB 155 5.4 eHMP4 112 87.3 +HMP3 241 77.3 +HMP2 84 32.7 +HCNB 151 15.6 eHYNG 320 -23 e

111

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