HR: 14:00h
AN: T23A-01    [Abstracts]
TI: Do the great Himalayan earthquakes occur on the plane of detachment?
AU: * Kayal, J
EM: jr_kayal@hotmail.com
AF: Indian School of Mines, Department of Applied Geophysics, Dhanbad, 826004, India
AU: Mooney, W D
EM: mooney@usgs.gov
AF: U.S. Geological Survey, 345 Middlefield Rd. MS 977, Menlo Park, CA 94025, United States
AB: The most accepted conceptual tectonic models of the Himalayan Seismic Belt (HSB) suggest that below the Main Central Thrust (MCT) lies the Basement Thrust Front (BTF), a 'ramp', the geometrical asperity that accumulates the tectonic stress due to collision tectonics, and the great earthquakes occur on the basement thrust/or on the plane of detachment that separates the Indian shield and the Himalayan sedimentary wedge. Some authors named it Main Himalayan Thrust (MHT). These models are based on the teleseismic data and geological/geophysical evidences. The microearthquake data and a relook into the source processes of the great earthquakes in the Himalaya do not support these models. The four known great (M~8.0) earthquakes in the Himalaya, from west to east, the 1905 Kangra, 1934 Bihar, 1897 Shillong and the 1950 Assam, occurred by different tectonic processes, and possibly none can be explained by the conceptual tectonic models of the HSB; each occurred in its own unique tectonic environment.
DE: 8104 Continental margins: convergent
DE: 8108 Continental tectonics: compressional
DE: 8118 Dynamics and mechanics of faulting (8004)
DE: 8123 Dynamics: seismotectonics
DE: 8125 Evolution of the Earth (0325)
SC: Tectonophysics [T]
MN: 2007 Joint Assembly