virgin river dcip report - university of british columbia · 2011. 1. 26. · virgin river dcip...

Data AcquisitionInversion

InterpretationDiscussion

Virgin River DCIP Report

Justin Granek1

1University of British Columbia

Geophysical Inversion Facility

Applied Geophysics, 2010

Justin Granek DCIP Report



Outline

1 Data AcquisitionLocationSurvey Specications

2 InversionData ErrorsDCIP2DDCIP3D

3 InterpretationCorrelationsSnowbird Tectonic Zone




LocationSurvey Specs

Outline








RegionalAthabasca Basin, Northern Saskatchewan

Northern Saskatchewan

South Central Athabasca Basin

NTS Reference 74 G/12





LocalWide Lake Grid

10 Lines runningNW-SE

Approximately 4kmlong each

Approximately 40line-km total





Outline








Electrode CongurationPole-Pole

Collected in Summer 2007-2008 by Patterson Geophysics Ltd.

Pole Spacing a = 150m

12 Stainless Steel Electrodes (Including Innites)





Electrode CongurationCurrent Advance Protocol

For Electrodes n=1:6

Advance in Increments of 75m

For Electrodes n=7:10

Advance in Increments of 150m

Data Collected at Current-Potential Electrode Spacings of...

75m, 150m, 225m, 300m, 375m, 450m, 525m, 600m, 675m, 750m,825m, 900m, 1050m, 1200m, 1350m, and 1500m.





HardwareInstrument Specications

Walcer TX9000 9.0 kW IP Transmitter

Walcer MG-12 Motor Generator

Two IRIS Instruments ELREC Pro Time DomainIP-Resistivity Receivers





DataFiles Provided to UBC-GIF

RES2DINV File (.dat)

Reduced data format for RES2DINV software

Excel Spreadsheet (.xls)

File containing most of the raw data:

Voltage (mV)

Current (A)

Self Potential (mV/V)

20 Chargeability Channels (mV/V)

Local Tx/Rx Electrode Coordinates

Reduced Excel Spreadsheet (.xls)

Reduced data format for plotting pseudo-sections from Excel





DataQuality

Duplicates

Data are mostly duplicated

Typically very similar

IP Data

Very noisy

Not very useful




Data ErrorsDCIP2DDCIP3D

Outline








Errors

Noise oor + 5% of each Datum

2D: Noise oor calculated as 90% of smallest value along line

3D: Noise oor calculated as 90% of smallest value





Outline








Survey Lines





Local Grid: Default ParametersData





Local Grid: Default ParametersInversion Results





UTM: Fine MeshData





UTM: Fine MeshInversion Results





Outline








UTM: Default ParametersInversion Parameters

Data 3582

Mesh 175 712 cells

Core Cell Size 75m×75m×37.5m

Reference Model 1000Ωm

Mist 4059





UTM: Default ParametersVertical Slice through Line 1200N





UTM: Default ParametersSurface View





UTM: Default Parameters375m Depth Slice





UTM: Default Parameters750m Depth Slice





UTM: Default ParametersResistivity Cuto of 300Ωm





ProblemsTopics worth Revisiting

Duplicated Data

IP Chargeability

Noisy Surface





Duplicated DataComparison at 600m Depth Slice





IP ChargeabilityDecay Curves





IP ChargeabilityInversion

Datum 554

Mesh 165 528 cells

Core Cell Size 75m×75m×37.5m

Mist 2539





IP Chargeability600m Depth Slice: Useful...?





Surface WeightingSurface View





Surface WeightingVertical Slice through Line 1200N





Surface Weighting375m Depth Slice





Surface Weighting750m Depth Slice




CorrelationsSnowbird Tectonic Zone

Outline








ZTEMRecall From Elliott's Presentation...





Outline








Snowbird Tectonic ZoneGraphitic Fault Oset




DiscussionFeedback, Questions & Opinions

What Do You Think?


virgin river dcip report - university of british columbia · 2011. 1. 26. · virgin river dcip...

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