Using convergence research to connect the 3D architecture of the Himalayan thrust wedge to the seismic hazard and risk in Western Nepal
Presenters: Prof. Dr. Michael Murphy, Prof. Dr. Michael H. Taylor, Dr. Sean Bemis, Dr. Richard Styron, Dr. Elaina Sutley
Moderator: Asst. Prof. Dr. Basanta Raj Adhikari
Date: September 13 (Sunday), 2020
Time: 20:00 NPT (+5:45 GMT)
Using Convergence Research to Connect the 3D architecture of the Himalayan thrust wedge to the seismic hazard and risk in Western Nepal
Michael Murphy2 , Michael H. Taylor1, Sean Bemis3, Richard Styron4, Elaina Sutley1, Andrew K.R. Hoxey1, Suoya Fan2, Basanta R. Adhikari5, Deepak Chamlagain4, John Matthew Cannon6
1University of Kansas, Department of Geology, 1414 Naismith Drive, Lawrence, KS, 2University of Houston, Department of Earth and Atmospheric Sciences, 3507 Cullen Blvd., Houston, TX, 3Virginia Tech, Department of Geosciences, 926 West Campus Drive Blacksburg, VA, 4GEM Foundation 21855 Bear Creek Road, Los Gatos, CA 5Department of Civil Engineering, Institute of Engineering (IOE), Central Campus, Pulchowk, Tribhuvan University, Nepal, 5Department of Geology, Tri-Chandra M. Campus, Tribhuvan University, Nepal, 6 University of Texas, San Antonio, Department of Geological Sciences, San Antonio, TX 78249.
Studies of historical and prehistoric earthquakes show that great (Mw 8+) Himalayan earthquakes nucleate on the Main Himalayan Thrust (MHT) and propagate up-dip to faults at the front of the range; these pose the largest regional seismic hazard as regions near the seismogenic portions of the MHT have highly populated cities. However, a growing body of evidence suggests that faults within the wedge are active with slip rates and magnitudes high enough to play a key role in Himalayan geodynamics and seismic hazard. In far western Nepal, a recently identified and well-exposed splay fault system referred to as the Western Nepal Fault System is a zone of faulting that cuts across the thrust wedge and is capable of generating large earthquakes.
In this webinar we share our study that’s just beginning and aimed at addressing two high-priority scientific problems with a pressing societal impact:
(1)What is the role of splay faults in Himalayan megathrust models?
(2)What controls the lateral segmentation of rupture zones (and hence maximum magnitude)?
We will walk you through the seismotectonic framework of the Himalaya and our current understanding of the geometry of the MHT. We will then describe our observations from western Nepal and describe our preliminary results on fault system characteristics. We will end by presenting a few scenarios on the seismic hazard and risk in western Nepal.