Active Tectonics of the Kashmir Himalaya, NW India: Implications for earthquake potential in the Kashmir Seismic Gap
About the Event:
In Kashmir, the Himalayan Frontal thrust is blind, characterized by a broad fold, the Suruin-Mastgarh anticline, and displays no emergent faults cutting either limb. Vector fold restoration of fluvial terrace profiles, bedrock dip data, and stratigraphic thickness indicate a deformation pattern controlled by a duplex structure emplaced at depth along the basal décollement, folding the overlying roof thrust and foreland strata into a detachment-like fold. Dated terraces from multiple OSL and 10Be TCN depth profiles ages across the frontal fold yield best-fit shortening rate of ~6 mm/yr since 44 ka. Active emergent thrust faulting is occurring north of the deformation front along the >60-km-long Riasi fault system. Multiple fault strands with Quaternary activity characterize the fault system near the Chenab River. Dated fluvial terraces across these fault strands indicate that a 6–7 mm/yr shortening rate characterized the Riasi fault system during the last 100 kyr. Contact relationships in a trench date the last surface rupture at ~4,500 yrs ago on the Riasi fault zone. Geodetic data indicate that an 11–13 mm/yr arc-normal shortening rate characterizes the interseismic strain accumulation across the plate boundary due to India-Tibet convergence. These data combined with rates of other active faults in the Kashmir Himalaya indicate that the shortening occurs at an equal rate between folding at the deformation front and the Riasi fault system to the north. A substantial slip deficit characterizes both structures and highlights the presence of a regionally important seismic gap in the Kashmir Himalaya. Slip deficit, scaling relationships, and a scenario of rupture and slip on the Main Himalayan thrust parsed onto either the Riasi fault system or the thrust front, or both, suggests that great earthquakes (Mw > 8) pose an even greater seismic hazard than the Mw 7.6 2005 earthquake on the Balakot-Bagh fault in Pakistan Azad Kashmir.
About the Speaker:
Oregon State University
Gavillot is currently a Research Associate at Oregon State University, and an Adjunct Instructor/Lecturer teaching field geology courses (Wyoming, Morocco, French Alps) for South Dakota School of Mines and Technology. Following his PhD, he continues to work on the active tectonics of the Kashmir Himalaya characterizing active faults and associated seismic sources, and Miocene-recent exhumation history across the thrust belt using low-temperature thermochronology. He is currently working on a new project with the U.S. Geologic Survey to refine structural geometry and slip rates estimates to improve seismic source models of blind faults in the Sacramento-San Joaquin Bay Delta of Northern California.
Gavillot has expertise in the fields of active tectonics, structural geology, tectonic geomorphology, earthquake geology, surface processes, low-temperature thermochronology, and Quaternary dating techniques. His research interests are focused on the investigation of crustal deformation at various spatial and time scales, from individual seismogenic faults to evolution of entire mountain belts. Gavillot is particularly interested in linking space-time behavior of faulting and deformation between earthquake cycles, millennial timescales, and long-term tectonic processes; and the feedback mechanisms between active tectonics, erosion, climate, and landscape evolution, which affect mountain building processes.
His prior work (2012-2015) as a Geologist Specialist at UNESCO Headquarters in Paris involved the development and coordination of various international projects in the field of Earth sciences and science policy, sustainable development best practices, and capacity building. Gavillot received his PhD (2014) from Oregon State University working with Andrew Meigs. For his MS (2008), he worked with Gary Axen and Brian Horton on an active tectonics and thermochronology study in the High Zagros fold-thrust belt (Iran). Gavillot is originally from Ile de la Réunion (French territory) east of Madagascar, and subsequently lived in southern France and in the USA (Arizona, California, and Oregon).