Subsurface Fault and Colluvial Wedge Detection Using Resistivity, Refraction Tomography and Seismic...
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Subsurface Fault and Colluvial Wedge Detection Using Resistivity, Refraction Tomography and Seismic Reflection Sherif Hanafy King Abdullah University of
Subsurface Fault and Colluvial Wedge Detection Using
Resistivity, Refraction Tomography and Seismic Reflection Sherif
Hanafy King Abdullah University of science and Technology
(KAUST)
Slide 2
Outline Motivations Methodology Study Area Data Acquisition
(Resistivity and Seismic) Data Processing and Interpretation
Resistivity Seismic Summary and Future Work
Slide 3
Outline Motivations Methodology Study Area Data Acquisition
(Resistivity and Seismic) Data Processing and Interpretation
Resistivity Seismic Summary and Future Work
Slide 4
Motivations 1.Demonstrate the capability of geophysics to
detect shallow subsurface faults 2.Is Qademah fault exists? 3.Track
the Qademah fault (if exist) 4.trenching and dating ancient
earthquakes at Qademah fault to assess size and recurrence
intervals
Slide 5
Outline Motivations Methodology Study Area Data Acquisition
(Resistivity and Seismic) Data Processing and Interpretation
Resistivity Seismic Summary and Future Work
Slide 6
Methodology Ground surface Depth ts are known, xs are know, and
ss are unknown
Slide 7
Outline Motivations Study Area Data Acquisition (Resistivity
and Seismic) Data Processing and Interpretation Resistivity Seismic
Summary and Future Work
Slide 8
KAUST Qadema Fault Study Area
Slide 9
Data Acquisition (Resistivity and Seismic)
Slide 10
Data Acquisition (Resistivity and Seismic)
Slide 11
Topography
Slide 12
Outline Motivations Study Area Data Acquisition (Resistivity
and Seismic) Data Processing and Interpretation Resistivity Seismic
Summary and Future Work
Slide 13
Data Acquisation Resistivity Equipment: Syscal R2 No. of
Profiles: 2 No. of Nodes: 64 Node Interval: 5 m Profile Length: 315
m Array Type: Wenner Seismic Equipment: Geometrics (NZXP + Geode)
No of Profiles: 1 No. of shots: 109 Shot Interval: 3 m No. of
Receivers: 109 Receiver Interval: 3 m Profile Length: 324 m
Slide 14
Outline Motivations Study Area Data Acquisition (Resistivity
and Seismic) Data Processing and Interpretation Resistivity Seismic
Summary and Future Work
Slide 15
Resistivity Results Site # 1 Raw Data No. of Nodes: 64 Node
Interval: 5 m Profile Length: 315 m Array Type: Wenner
Slide 16
Resistivity Results Site # 1 Inverted Data S SabkhaCW Colluvial
Wedge F FanSG Sand-silt-gravel LS Limestone
Slide 17
Resistivity Results Site # 2 Raw Data No. of Nodes: 64 Node
Interval: 5 m Profile Length: 315 m Array Type: Wenner
Slide 18
Resistivity Results Site # 2 Inverted Data S SabkhaCW Colluvial
Wedge F FanSG Sand-silt-gravel LS Limestone
Slide 19
Outline Motivations Study Area Data Acquisition (Resistivity
and Seismic) Data Processing and Interpretation Resistivity Seismic
Summary and Future Work
Slide 20
No. of shots: 109 Shot Interval: 3 m No. of Receivers: 109
Receiver Interval: 3 m Profile Length: 324 m CSG # 60 0 0.25 0 324
X (m) Time (s) Common Shot Gather No of TT: 11881 TT passes Reci.
Test: 9488 No. of TT rejected: 2393 No. of Iterations: 40
Slide 21
Refraction Tomogram
Slide 22
Reflection Stacked Section
Slide 23
Slide 24
Result Summary
Slide 25
Outline Motivations Study Area Data Acquisition (Resistivity
and Seismic) Data Processing and Interpretation Resistivity Seismic
Summary and Future Work
Slide 26
Resistivity and seismic methods used to detect the Qademah
fault One colluvial wedge is shown on both ERT and refraction
tomogram Reflection stacked section shows the Qademah fault and the
associated antithetic fault(s)
Slide 27
Summary and Future Work The Qademah Fault will be tracked to
the south with Seismic Resistivity EM and possibly GPR A trench
will be made at Qademah fault to date the colluvial wedge If more
than one colluvial wedge is found, then we will be able to find the
fault recurrence.