deciphering the role of fluids in early stage rifting from...
TRANSCRIPT
33.0˚ 34.0˚ 35.0˚−11.0˚
−10.0˚
−9.0˚
33.6˚ 33.7˚ 33.8˚ 33.9˚ 34.0˚−10.0˚
−9.9˚
−9.8˚
−9.7˚
−9.6˚
Deciphering the role of fluids in early stage rifting from full moment tensor inversion of East African earthquakes S.J. Oliva1 ([email protected]), C.J. Ebinger1, S.W. Roecker2, D.B. Keir3, D.J. Shillington4, P. Chindandali5
1U. of Rochester (USA), 2Rensselaer Polytechnic Inst. (USA), 3U. of Southampton (UK), 4LDEO, Columbia U. (USA), 5Geological Survey of Malawi (Malawi)
1. Introduction 3. Magmatic sector: Kenya - Northern Tanzania 5. Discussion
2. Full moment tensor inversion
The East African Rift splits around the Archaean Tanzania craton into the magmatic Eastern branch and the mostly amagmatic Western branch. The EARS is the site of lower crustal EQs and active magma intrusion, enabling detection of a broad range of rifting processes and providing insights into the early rifting.
Focus: Is brittle strain accommodated by shear in magmatic and amagmatic rift sectors, or do magma and volatile flow add a significant isotropic component? Are there differences between unusual lower crustal EQs and shallow EQs?
(Adapted from Dawson, 2008)
Chapter 1
Introduction
There are only a few areas on Earth where continental platebreak-up and the attendant magmatism are taking place at thepresent day. In this context, the East African Rift system takespride of place as it is the most extensive, presently active,continental extension zone, the extension being accompanied
by seismicity, crustal thinning and, in some sectors, magmatism.The reason for this spectacular fracturing of the African Platehas been the subject of much debate but there is general consensusthat it is due, at least in part, to the presence of rising thermalplumes in the mantle beneath Africa. The extension is now held
Fig. 1.1. Map of East Africa, showing the plate tectonic position of the North Tanzania Divergence relative to the Red Sea spreading centre, and the main structural units
of the Ethiopian and Kenya domes and the Tanzania Craton.
J. B. Dawson, University of Edinburgh ( [email protected])From: DAWSON, J. B. 2008. The Gregory Rift Valley and Neogene–Recent Volcanoes of Northern Tanzania. Geological Society, London, Memoirs, 33, 1–2.
0435-4052/08/$15.00 # The Geological Society of London 2008. DOI: 10.1144/M33.1
at Marie Curie Library - The Abdus Salam ICTP on July 20, 2015http://mem.lyellcollection.org/Downloaded from
4. Amagmatic sector: Northern Malawi
Acknowledgments
✦ Dreger & Ford TDMT algorithm ✦ full waveforms, TRV components ✦ MT decompositions capture different mechanisms
✦ DC : shear faulting ✦ ISO : tensile opening ✦ CLVD : non-∆V DC deviation
✦ uses a 1D velocity model ✦ from a seismic line, north of the region
✦ largest variance reduction = best fit ✦ improved source depth estimate ✦ bp filter 0.02 - 0.10 Hz, or range within ✦ non-ISO vs ISO solution:
✦ EVT1 and EVT2: Two significant-sized EQs within a day of the same mechanism, with a big isotropic component as shown in this inversion = an intrusion? — awaiting inSAR results on this
✦ Suggests reinterpretation of shallow magma chamber of the Biggs et al (2009, 2013) geodetic model based on InSAR
Full moment tensor inversion uses Dreger and Ford TDMT-INVC algorithm (Dreger, 2003; Minson & Dreger, 2008). Many thanks to N. Lindsey for assistance in learning this code. Support from NSF, ANR, IRIS/PASSCAL gratefully acknowledged.
36
-3
-2.5
< 5<10<15<20<30<40<50
Gelai
Songob.f.
NATRONBASIN
OLNS
Lo
F1F3
Manyarab.f
K
Kitumbeine
Engaruka tf
F2
F4
Em
C C’
C C’
-30
-20
-10
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2.5 3.0 3.5 4.0
Vs
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-25
-15
-5
0 10 20 30 40 50 60
5
0
1
2
3
S. flank Gelai volcano
NaiborSoito monogenetic cones
N. flank, OldoinyoLengai volcano
Songo borderfault
Natron Basin
km
km
km
W E2007 dike intrusion
Mw5.9
36E
magma body
17/7/2007
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magma body
sedimentary strata
Mosonik
v
B B’
B B’
Manyarabasin
magma intrusion zone local stress field rotation
RIFTSEGMENTLINKAGE VIA MAGMAINTRUSION
strainby slip alongborder fault
strainby magma intrusionand slip alongborder fault
Gelai volcano
Gelai
dike intrusion zone
?
OldoinyoLengai
ca. 15 km
Naibor Soitomonogeneticcones
NSOL
Border fault
Magadibasin
Natronbasin
✦ Geometry of earthquakes close to the region of the 2007 diking could be indicative of a sill (Weinstein et al, submitted)
✦ Strain accommodation via non-DC mechanisms (indicative of fluids?) supports the magma-driven model of rifting
Tanganyika rift
Malawi rift
✦ ISO component can be significant, important to consider ✦ May be indicative of fluid activity
T51C-2942
35.8˚ 35.9˚ 36.0˚ 36.1˚ 36.2˚−2.9˚
−2.8˚
−2.7˚
−2.6˚
−2.5˚
35.0˚ 36.0˚ 37.0˚ 38.0˚−6.0˚
−5.0˚
−4.0˚
−3.0˚
−2.0˚
−1.0˚
M1M2M3M4M5
Gelai
Oldoinyo Lengai
Kerimasi
border fault
EVT1
EVT2
EVT3
EVT4
EVT5
EVT6
0 5 10 15 20 25 30 35 40 45 50Depth (km)
Tangential Radial Vertical
MW43.data
Distance = 33 km Azimuth = 211 Max Amp = 1.39e−03 cm Zcorr = 7 VR = 50 30.00 sec
LN46.data
Distance = 64 km Azimuth = 96 Max Amp = 8.46e−04 cm Zcorr = 11 VR = 73 30.00 sec
LN26.data
Distance = 44 km Azimuth = 326 Max Amp = 4.12e−03 cm Zcorr = 6 VR = 39 30.00 sec
LN25.data
Distance = 54 km Azimuth = 334 Max Amp = 3.77e−03 cm Zcorr = 7 VR = 48 30.00 sec
LN14.data
Distance = 66 km Azimuth = 32 Max Amp = 4.44e−04 cm Zcorr = 9 VR = 6 30.00 sec
LL24.data
Distance = 82 km Azimuth = 337 Max Amp = 8.01e−04 cm Zcorr = 9 VR = −16 30.00 sec
�
page 1 of 2
Tangential Radial Vertical
PR63.data
Distance = 63 km Azimuth = 245 Max Amp = 6.84e−05 cm Zcorr = 4 VR = 0 22.50 sec
PR61.data
Distance = 89 km Azimuth = 255 Max Amp = 5.84e−05 cm Zcorr = 7 VR = 33 22.50 sec
NG55.data
Distance = 57 km Azimuth = 221 Max Amp = 1.15e−04 cm Zcorr = 6 VR = 66 22.50 sec
MW43.data
Distance = 51 km Azimuth = 189 Max Amp = 1.60e−04 cm Zcorr = 5 VR = 53 22.50 sec
LN15.data
Distance = 23 km Azimuth = 54 Max Amp = 3.11e−04 cm Zcorr = 0 VR = 23 22.50 sec
LL24.data
Distance = 58 km Azimuth = 336 Max Amp = 1.71e−04 cm Zcorr = 4 VR = 85 22.50 sec
�
page 1 of 2
Tangential Radial Vertical
NG55.data
Distance = 60 km Azimuth = 217 Max Amp = 2.34e−04 cm Zcorr = 6 VR = 57 22.50 sec
NG54.data
Distance = 72 km Azimuth = 268 Max Amp = 8.06e−05 cm Zcorr = 6 VR = 50 22.50 sec
LN26.data
Distance = 18 km Azimuth = 307 Max Amp = 2.29e−04 cm Zcorr = 2 VR = 34 22.50 sec
LN25.data
Distance = 27 km Azimuth = 329 Max Amp = 1.95e−04 cm Zcorr = 3 VR = 39 22.50 sec
LN15.data
Distance = 21 km Azimuth = 65 Max Amp = 2.16e−04 cm Zcorr = 0 VR = 29 22.50 sec
LN14.data
Distance = 54 km Azimuth = 56 Max Amp = 7.62e−05 cm Zcorr = 6 VR = 76 22.50 sec
�
page 1 of 2
Tangential Radial Vertical
LN34.data
22.50 sec
LL65.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
PR52.data
22.50 sec
PR61.data
22.50 sec
�
page 2 of 2
Sample waveform fitsEvent
EVT12013-06-03 03:24Ml 4.40, 8 km depth
% DC 30 % CLVD 32 % ISO 39
Tangential Radial Vertical
MW43.data
30.00 sec
LN46.data
30.00 sec
LN26.data
30.00 sec
LN25.data
30.00 sec
LN14.data
30.00 sec
LL24.data
30.00 sec
�
page 1 of 2Tangential Radial Vertical
MW43.data
30.00 sec
LN46.data
30.00 sec
LN26.data
30.00 sec
LN25.data
30.00 sec
LN14.data
30.00 sec
LL24.data
30.00 sec
�
page 1 of 2
Tangential Radial Vertical
MW43.data
30.00 sec
LN46.data
30.00 sec
LN26.data
30.00 sec
LN25.data
30.00 sec
LN14.data
30.00 sec
LL24.data
30.00 sec
�
page 1 of 2
Tangential Radial Vertical
LL23.data
30.00 sec
NBI.data
30.00 sec
KMBO.data
30.00 sec
�LL23.data
NBI.dataKMBO.data
Depth = 8Strike = 262 ; 47Rake = −66 ; −117Dip = 51 ; 44Mo = 1.40e+23Mw = 4.71Percent DC = 30Percent CLVD = 32Percent ISO = 39Variance = 1.88e−07Var. Red. = 43.0
page 2 of 2
EVT22013-06-03 09:53Ml 4.38, 8 km depth
EVT32014-08-04 03:06Ml 3.68, 11 km depth
% DC 48 % CLVD 40 % ISO 12
EVT42014-09-05 17:54Ml 3.60, 8 km depth
% DC 37 % CLVD 28 % ISO 36
% DC 33 % CLVD 42 % ISO 25
EVT52014-09-19 19:50Ml 3.50, 7 km depth
% DC 65 % CLVD 30 % ISO 5
EVT62014-10-31 17:50Ml 5.1, 21 km depth
% DC 49 % CLVD 29 % ISO 31
Tangential Radial Vertical
PR63.data
30.00 sec
PR33.data
30.00 sec
PR11.data
30.00 sec
NG56.data
30.00 sec
NG54.data
30.00 sec
MW36.data
30.00 sec
�
PR63.dataPR33.data
PR11.dataNG56.data
NG54.data
MW36.data
Depth = 8Strike = 260 ; 32Rake = −64 ; −132Dip = 64 ; 36Mo = 5.20e+23Mw = 5.08Percent DC = 37Percent CLVD = 28Percent ISO = 36Variance = 6.00e−07Var. Red. = 44.4
page 1 of 2
Tangential Radial Vertical
PR63.data
30.00 sec
PR33.data
30.00 sec
PR11.data
30.00 sec
NG56.data
30.00 sec
NG54.data
30.00 sec
MW36.data
30.00 sec
�
PR63.dataPR33.data
PR11.dataNG56.data
NG54.data
MW36.data
Depth = 8Strike = 260 ; 32Rake = −64 ; −132Dip = 64 ; 36Mo = 5.20e+23Mw = 5.08Percent DC = 37Percent CLVD = 28Percent ISO = 36Variance = 6.00e−07Var. Red. = 44.4
page 1 of 2
Tangential Radial Vertical
LN26.data
30.00 sec
LN25.data
30.00 sec
LN15.data
30.00 sec
LL65.data
30.00 sec
LL23.data
30.00 sec
�
LN26.data
LN25.data
LN15.dataLL65.data
LL23.data
Depth = 8Strike = 260 ; 32Rake = −64 ; −132Dip = 64 ; 36Mo = 5.20e+23Mw = 5.08Percent DC = 37Percent CLVD = 28Percent ISO = 36Variance = 6.00e−07Var. Red. = 44.4
page 2 of 2
Tangential Radial Vertical
PR63.data
30.00 sec
PR33.data
30.00 sec
PR11.data
30.00 sec
NG56.data
30.00 sec
NG54.data
30.00 sec
MW36.data
30.00 sec
�
PR63.dataPR33.data
PR11.dataNG56.data
NG54.data
MW36.data
Depth = 8Strike = 260 ; 32Rake = −64 ; −132Dip = 64 ; 36Mo = 5.20e+23Mw = 5.08Percent DC = 37Percent CLVD = 28Percent ISO = 36Variance = 6.00e−07Var. Red. = 44.4
page 1 of 2
Tangential Radial Vertical
PR63.data
22.50 sec
PR61.data
22.50 sec
NG55.data
22.50 sec
MW43.data
22.50 sec
LN15.data
22.50 sec
LL24.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
LL66.data
22.50 sec
LL24.data
22.50 sec
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
LL66.data
22.50 sec
LL24.data
22.50 sec
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
LL66.data
22.50 sec
LL24.data
22.50 sec
LL23.data
22.50 sec
LL22.data
22.50 sec
KEN3.data
22.50 sec
KEN2.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
NG55.data
22.50 sec
NG54.data
22.50 sec
LN26.data
22.50 sec
LN25.data
22.50 sec
LN15.data
22.50 sec
LN14.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
PR33.data
22.50 sec
PR31.data
22.50 sec
PR11.data
22.50 sec
NG55.data
22.50 sec
MW44.data
22.50 sec
LN46.data
22.50 sec
�
page 1 of 2Tangential Radial Vertical
PR33.data
22.50 sec
PR31.data
22.50 sec
PR11.data
22.50 sec
NG55.data
22.50 sec
MW44.data
22.50 sec
LN46.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
PR33.data
22.50 sec
PR31.data
22.50 sec
PR11.data
22.50 sec
NG55.data
22.50 sec
MW44.data
22.50 sec
LN46.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
LN34.data
22.50 sec
LL65.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
JILO.data
22.50 sec
KIPE.data
22.50 sec
LL65.data
22.50 sec
LOSI.data
22.50 sec
MBAR.data
22.50 sec
NG56.data
22.50 sec
�
page 1 of 2Tangential Radial Vertical
JILO.data
22.50 sec
KIPE.data
22.50 sec
LL65.data
22.50 sec
LOSI.data
22.50 sec
MBAR.data
22.50 sec
NG56.data
22.50 sec
�
page 1 of 2Tangential Radial Vertical
JILO.data
22.50 sec
KIPE.data
22.50 sec
LL65.data
22.50 sec
LOSI.data
22.50 sec
MBAR.data
22.50 sec
NG56.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
PR52.data
22.50 sec
PR61.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
MW43.data
Distance = 33 km Azimuth = 211 Max Amp = 1.39e−03 cm Zcorr = 7 VR = 50 30.00 sec
LN46.data
Distance = 64 km Azimuth = 96 Max Amp = 8.46e−04 cm Zcorr = 11 VR = 73 30.00 sec
LN26.data
Distance = 44 km Azimuth = 326 Max Amp = 4.12e−03 cm Zcorr = 6 VR = 39 30.00 sec
LN25.data
Distance = 54 km Azimuth = 334 Max Amp = 3.77e−03 cm Zcorr = 7 VR = 48 30.00 sec
LN14.data
Distance = 66 km Azimuth = 32 Max Amp = 4.44e−04 cm Zcorr = 9 VR = 6 30.00 sec
LL24.data
Distance = 82 km Azimuth = 337 Max Amp = 8.01e−04 cm Zcorr = 9 VR = −16 30.00 sec
�
page 1 of 2
Tangential Radial Vertical
MW43.data
Distance = 33 km Azimuth = 211 Max Amp = 1.39e−03 cm Zcorr = 6 VR = 35 30.00 sec
LN46.data
Distance = 64 km Azimuth = 96 Max Amp = 8.46e−04 cm Zcorr = 11 VR = 68 30.00 sec
LN26.data
Distance = 44 km Azimuth = 326 Max Amp = 4.12e−03 cm Zcorr = 6 VR = 38 30.00 sec
LN25.data
Distance = 54 km Azimuth = 334 Max Amp = 3.77e−03 cm Zcorr = 7 VR = 46 30.00 sec
LN14.data
Distance = 66 km Azimuth = 32 Max Amp = 4.44e−04 cm Zcorr = 9 VR = 3 30.00 sec
LL24.data
Distance = 82 km Azimuth = 337 Max Amp = 8.01e−04 cm Zcorr = 9 VR = −15 30.00 sec
�
page 1 of 2Tangential Radial Vertical
LN26.data
Distance = 16 km Azimuth = 305 Max Amp = 4.19e−03 cm Zcorr = 7 VR = 52 30.00 sec
LN25.data
Distance = 25 km Azimuth = 330 Max Amp = 3.30e−03 cm Zcorr = 6 VR = 61 30.00 sec
LN15.data
Distance = 22 km Azimuth = 70 Max Amp = 2.66e−03 cm Zcorr = 8 VR = 26 30.00 sec
LL65.data
Distance = 70 km Azimuth = 296 Max Amp = 3.69e−03 cm Zcorr = 14 VR = 31 30.00 sec
LL23.data
Distance = 56 km Azimuth = 322 Max Amp = 1.80e−03 cm Zcorr = 8 VR = 37 30.00 sec
�
page 2 of 2
deviatoric solution
isotropic solution
EVT1-Tanz EVT2-Tanz EVT7-Mlwi
% DC 99 % CLVD 1 % ISO 0
% DC 30 % CLVD 32 % ISO 39
% DC 98 % CLVD 2 % ISO 0
% DC 37 % CLVD 28 % ISO 36
Tangential Radial Vertical
THAN.data
Distance = 163 km Azimuth = 168 Max Amp = 5.74e−03 cm Zcorr = 14 VR = 28 30.00 sec
MLOW.data
Distance = 91 km Azimuth = 156 Max Amp = 1.01e−02 cm Zcorr = 6 VR = 58 30.00 sec
ZINI.data
Distance = 168 km Azimuth = 107 Max Amp = 1.18e−02 cm Zcorr = 11 VR = 75 30.00 sec
NGEA.data
Distance = 211 km Azimuth = 110 Max Amp = 1.42e−02 cm Zcorr = 17 VR = 44 30.00 sec
LIGA.data
Distance = 168 km Azimuth = 116 Max Amp = 9.85e−03 cm Zcorr = 12 VR = 75 30.00 sec
KURU.data
Distance = 217 km Azimuth = 127 Max Amp = 1.08e−02 cm Zcorr = 19 VR = 58 30.00 sec
�
page 1 of 3
% DC 53 % CLVD 28 % ISO 19
Tangential Radial Vertical
THAN.data
Distance = 163 km Azimuth = 168 Max Amp = 5.72e−03 cm Zcorr = 14 VR = 21 30.00 sec
MLOW.data
Distance = 91 km Azimuth = 156 Max Amp = 8.35e−03 cm Zcorr = 6 VR = 47 30.00 sec
ZINI.data
Distance = 168 km Azimuth = 107 Max Amp = 1.18e−02 cm Zcorr = 11 VR = 74 30.00 sec
NGEA.data
Distance = 211 km Azimuth = 110 Max Amp = 1.41e−02 cm Zcorr = 17 VR = 44 30.00 sec
LIGA.data
Distance = 168 km Azimuth = 116 Max Amp = 9.95e−03 cm Zcorr = 12 VR = 74 30.00 sec
KURU.data
Distance = 217 km Azimuth = 127 Max Amp = 1.09e−02 cm Zcorr = 19 VR = 56 30.00 sec
�
page 1 of 3
% DC 89 % CLVD 11 % ISO 0
Sample waveform fitsEvent
EVT72014-12-31 19:47Mw 5.1, 6 km depth
% DC 53 % CLVD 28 % ISO 19
EVT82014-12-31 20:41 5 km depth
% DC 61 % CLVD 33 % ISO 6
EVT92015-01-01 00:33
10 km depth
% DC 52 % CLVD 42 % ISO 6
Tangential Radial Vertical
THAN.data
30.00 sec
MLOW.data
30.00 sec
ZINI.data
30.00 sec
NGEA.data
30.00 sec
LIGA.data
30.00 sec
KURU.data
30.00 sec
�
THAN.dataMLOW.data
ZINI.dataNGEA.dataLIGA.data
KURU.data
Depth = 6Strike = 9 ; 160Rake = −72 ; −113Dip = 53 ; 41Mo = 2.80e+24Mw = 5.57Percent DC = 53Percent CLVD = 28Percent ISO = 19Variance = 2.25e−06Var. Red. = 60.6
page 1 of 3
Tangential Radial Vertical
CHML.data
30.00 sec
WINO.data
30.00 sec
MKIL.data
30.00 sec
MBAM.data
30.00 sec
LOSI.data
30.00 sec
JILO.data
30.00 sec
�CHML.data
WINO.data
MKIL.dataMBAM.data
LOSI.dataJILO.data
Depth = 6Strike = 9 ; 160Rake = −72 ; −113Dip = 53 ; 41Mo = 2.80e+24Mw = 5.57Percent DC = 53Percent CLVD = 28Percent ISO = 19Variance = 2.25e−06Var. Red. = 60.6
page 2 of 3
Tangential Radial Vertical
CHML.data
30.00 sec
WINO.data
30.00 sec
MKIL.data
30.00 sec
MBAM.data
30.00 sec
LOSI.data
30.00 sec
JILO.data
30.00 sec
�CHML.data
WINO.data
MKIL.dataMBAM.data
LOSI.dataJILO.data
Depth = 6Strike = 9 ; 160Rake = −72 ; −113Dip = 53 ; 41Mo = 2.80e+24Mw = 5.57Percent DC = 53Percent CLVD = 28Percent ISO = 19Variance = 2.25e−06Var. Red. = 60.6
page 2 of 3
Tangential Radial Vertical
GAWA.data
30.00 sec
MBEY.data
30.00 sec
� GAWA.dataMBEY.data
Depth = 6Strike = 9 ; 160Rake = −72 ; −113Dip = 53 ; 41Mo = 2.80e+24Mw = 5.57Percent DC = 53Percent CLVD = 28Percent ISO = 19Variance = 2.25e−06Var. Red. = 60.6
page 3 of 3
Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
�
page 1 of 2Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
�
page 1 of 2
Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
�
page 1 of 1Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
�
page 1 of 1
Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
�
page 1 of 1Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
�
page 1 of 1
EVT9
EVT7
EVT8
Tangential Radial Vertical
THAN.data
Distance = 163 km Azimuth = 168 Max Amp = 5.74e−03 cm Zcorr = 14 VR = 28 30.00 sec
MLOW.data
Distance = 91 km Azimuth = 156 Max Amp = 1.01e−02 cm Zcorr = 6 VR = 58 30.00 sec
ZINI.data
Distance = 168 km Azimuth = 107 Max Amp = 1.18e−02 cm Zcorr = 11 VR = 75 30.00 sec
NGEA.data
Distance = 211 km Azimuth = 110 Max Amp = 1.42e−02 cm Zcorr = 17 VR = 44 30.00 sec
LIGA.data
Distance = 168 km Azimuth = 116 Max Amp = 9.85e−03 cm Zcorr = 12 VR = 75 30.00 sec
KURU.data
Distance = 217 km Azimuth = 127 Max Amp = 1.08e−02 cm Zcorr = 19 VR = 58 30.00 sec
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0 5 10 15 20 25 30 35 40 45 50Depth (km)
Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
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Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
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✦ CRAFTI broadband seismic array, 2013-2014 ✦ M > 3.5 with good azimuthal coverage (for EVT6, the SEGMeNT array in SW
complements CRAFTI) ✦ EVT1-5, source-to-receiver distances < 200 km
✦ SEGMeNT array, 2014-12-31 EQ sequence ✦ EVT7-9, source-to-receiver distances < 200 km
✦ Shallow extensional and strike-slip events, similar to 2009 Karonga sequence
✦ Unruptured segment during the 2009 sequence? Though not as strong
✦ Shallow Mw5.1 EQ may have triggered slip on faults in lower crust, with strike-slip mechanisms possibly associated with linkage to faults that slipped in 2009
✦ First motion analyses of full aftershock sequence to test fault linkage hypothesis
✦ Smaller volumetric components of FMT in amagmatic compared to magmatic sectors, suggesting less fluid activity or different mechanism of activity
✦ Significant CLVD in all FMTs probably due to fluids
(Weinstein et al, 2016)
(Weinstein et al, 2016)
(Adapted from Gaherty et al, AGU 2012; Faults after Ebinger 1993; Mortimer et al, 2007; Biggs et al, 2010; Bathymetry from Lyons et al, 2011)
Tangential Radial Vertical
MW43.data
Distance = 33 km Azimuth = 211 Max Amp = 1.39e−03 cm Zcorr = 7 VR = 50 30.00 sec
LN46.data
Distance = 64 km Azimuth = 96 Max Amp = 8.46e−04 cm Zcorr = 11 VR = 73 30.00 sec
LN26.data
Distance = 44 km Azimuth = 326 Max Amp = 4.12e−03 cm Zcorr = 6 VR = 39 30.00 sec
LN25.data
Distance = 54 km Azimuth = 334 Max Amp = 3.77e−03 cm Zcorr = 7 VR = 48 30.00 sec
LN14.data
Distance = 66 km Azimuth = 32 Max Amp = 4.44e−04 cm Zcorr = 9 VR = 6 30.00 sec
LL24.data
Distance = 82 km Azimuth = 337 Max Amp = 8.01e−04 cm Zcorr = 9 VR = −16 30.00 sec
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Tangential Radial Vertical
PR63.data
Distance = 63 km Azimuth = 245 Max Amp = 6.84e−05 cm Zcorr = 4 VR = 0 22.50 sec
PR61.data
Distance = 89 km Azimuth = 255 Max Amp = 5.84e−05 cm Zcorr = 7 VR = 33 22.50 sec
NG55.data
Distance = 57 km Azimuth = 221 Max Amp = 1.15e−04 cm Zcorr = 6 VR = 66 22.50 sec
MW43.data
Distance = 51 km Azimuth = 189 Max Amp = 1.60e−04 cm Zcorr = 5 VR = 53 22.50 sec
LN15.data
Distance = 23 km Azimuth = 54 Max Amp = 3.11e−04 cm Zcorr = 0 VR = 23 22.50 sec
LL24.data
Distance = 58 km Azimuth = 336 Max Amp = 1.71e−04 cm Zcorr = 4 VR = 85 22.50 sec
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Tangential Radial Vertical
NG55.data
Distance = 60 km Azimuth = 217 Max Amp = 2.34e−04 cm Zcorr = 6 VR = 57 22.50 sec
NG54.data
Distance = 72 km Azimuth = 268 Max Amp = 8.06e−05 cm Zcorr = 6 VR = 50 22.50 sec
LN26.data
Distance = 18 km Azimuth = 307 Max Amp = 2.29e−04 cm Zcorr = 2 VR = 34 22.50 sec
LN25.data
Distance = 27 km Azimuth = 329 Max Amp = 1.95e−04 cm Zcorr = 3 VR = 39 22.50 sec
LN15.data
Distance = 21 km Azimuth = 65 Max Amp = 2.16e−04 cm Zcorr = 0 VR = 29 22.50 sec
LN14.data
Distance = 54 km Azimuth = 56 Max Amp = 7.62e−05 cm Zcorr = 6 VR = 76 22.50 sec
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Tangential Radial Vertical
LN34.data
22.50 sec
LL65.data
22.50 sec
�
page 2 of 2
Tangential Radial Vertical
PR52.data
22.50 sec
PR61.data
22.50 sec
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page 2 of 2
Tangential Radial Vertical
THAN.data
Distance = 163 km Azimuth = 168 Max Amp = 5.74e−03 cm Zcorr = 14 VR = 28 30.00 sec
MLOW.data
Distance = 91 km Azimuth = 156 Max Amp = 1.01e−02 cm Zcorr = 6 VR = 58 30.00 sec
ZINI.data
Distance = 168 km Azimuth = 107 Max Amp = 1.18e−02 cm Zcorr = 11 VR = 75 30.00 sec
NGEA.data
Distance = 211 km Azimuth = 110 Max Amp = 1.42e−02 cm Zcorr = 17 VR = 44 30.00 sec
LIGA.data
Distance = 168 km Azimuth = 116 Max Amp = 9.85e−03 cm Zcorr = 12 VR = 75 30.00 sec
KURU.data
Distance = 217 km Azimuth = 127 Max Amp = 1.08e−02 cm Zcorr = 19 VR = 58 30.00 sec
�
page 1 of 3
Tangential Radial Vertical
NGON.data
22.50 sec
MLOW.data
22.50 sec
KAPK.data
22.50 sec
ZINI.data
22.50 sec
LOSI.data
22.50 sec
IGOM.data
22.50 sec
�
page 1 of 1
Tangential Radial Vertical
KALO.data
22.50 sec
THAZ.data
22.50 sec
KARM.data
22.50 sec
KIPE.data
22.50 sec
UWEM.data
22.50 sec
NKAL.data
22.50 sec
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page 1 of 2
Rungwe
Lake Malawi (Lake Nyasa)
Karonga
Livingstone fault
12/12/2009
12/08/2009
12/06/2009
12/19/2009