Imaging Normal Faults in Alluvial fans using Geophysical

Outline • • Motivation: Faults in alluvial sediments Study Area: Gulf of Aqaba Data

Motivation Can we locate and characterize faults in alluvial sediments? We used seismic traveltime

Data Acquisition Fault rupture due to 1995 earthquake. Photo taken on Nov. 2013 Another

Seismic Data Common Shot Gather # 1 0. 0 Time (s) First arrival traveltimes

Traveltime Picks Raw Picking After Reciprocity 1 Source No. 1 120 1 Receiver No.

RMS Error RMS error (ms) 0. 04 0. 0 Itr. No. 40

Seismic Tomogram First arrival traveltime picks are inverted to get the traveltime tomogram Unidentified

Resistivity The Res 2 DInv software is used to invert the resistivity data Z

Seismic - Resistivity A possible Colluvial Wedge Unidentified Anomaly The 1995 fault A possible

Conclusions • Seismic and resistivity methods can be used to locate hidden faults in

Future Work Seismic reflection processing to generate the zero-stacked section. Use the traveltime tomogram

Acknowledgements I would like to thank • The CSIM sponsors for their support •

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Imaging Normal Faults in Alluvial fans using Geophysical Techniques: Field Example from the Coast of Aqaba, Saudi Arabia Sherif M. Hanafy 28 October 2014

Outline • • Motivation: Faults in alluvial sediments Study Area: Gulf of Aqaba Data Acquisition: Seismic and resistivity Seismic Result: Traveltime tomography Resistivity Result: 2 D imaging Conclusions Future Work

Motivation Can we locate and characterize faults in alluvial sediments? We used seismic traveltime tomography and 2 D resistivity imaging to locate the fault

Gulf of A qaba Study Area Red Sea

Study Area Fault raptured at the 1995 earthquake Seismic/resistivity profile

Data Acquisition • Seismic Data – – – One profile 120 shot gather, 120 receiver/shot gather 2. 5 m shot/receiver interval 297. 5 m profile length 15 -20 stacks/shot location Source is a 200 lb weight drop • Resistivity – – 64 Nodes 5 m node interval 315 m profile length Wenner-Schlumberger configuration

Data Acquisition Fault rupture due to 1995 earthquake. Photo taken on Nov. 2013 Another location of the fault rapture due to 1995 earthquake. Photo taken on Nov. 2013

Data Acquisition Source: 200 lb weight drop Resistivity profile Seismic profile A photo shows the seismic and resistivity acquisition

Seismic Data Common Shot Gather # 1 0. 0 Time (s) First arrival traveltimes 0. 3 0. 0 297 Offset (m)

Traveltime Picks Raw Picking After Reciprocity 1 Source No. 1 120 1 Receiver No. Time (ms) 0 210 120

RMS Error RMS error (ms) 0. 04 0. 0 Itr. No. 40

Seismic Tomogram First arrival traveltime picks are inverted to get the traveltime tomogram Unidentified Anomaly A possible Colluvial Wedge The 1995 fault A possible fault

Resistivity The Res 2 DInv software is used to invert the resistivity data Z (m) 0 45 0 315 X (m) Resistivity (Ohm. m) 1 500

Seismic - Resistivity A possible Colluvial Wedge Unidentified Anomaly The 1995 fault A possible fault Z (m) 0 45 0 315 X (m) Resistivity (Ohm. m) 1 500

Conclusions • Seismic and resistivity methods can be used to locate hidden faults in the subsurface. • One example is collected at the Gulf of Aqaba coast. • Results show the location of fault due to the 1995 earthquake. • Possible local anomalies are shown on the traveltime tomogram and the 2 D resistivity image. • Further study is required to explain the nature of these local anomalies

Future Work Seismic reflection processing to generate the zero-stacked section. Use the traveltime tomogram to migrate the data Common Shot Gather # 1 Time (s) 0. 0 0. 3 0. 0 297 Offset (m)

Acknowledgements I would like to thank • The CSIM sponsors for their support • The the students of the “Geophysical Field Methods” class for their help in data collection Thank You