HR: 16:45h
AN: T54C-04    [Abstracts]
TI: Intensity, magnitude, location and attenuation in India for felt earthquakes since 1764
AU: Martin, S
EM: stacey.martin@asc-india.org
AF: Amateur Seismic Centre, Pune, Maharashtra, 411001, India
AU: * Szeliga, W
EM: szeliga@colorado.edu
AF: University of Colorado, 2200 Colorado Ave, Boulder, CO 80309-0399, United States
AU: Bilham, R
EM: bilham@colorado.edu
AF: University of Colorado, 2200 Colorado Ave, Boulder, CO 80309-0399, United States
AB: We have subjected more than 7444 intensity reports from 204 earthquakes in India that have occurred since 1764 to a felt-intensity vs attenuation analysis using the methods of Bakun and Wentworth (1997). Our catalog consists entirely of re-evaluated MSK intensities from authentic accounts. We include the 43 north Indian earthquakes analyzed by Ambraseys and Douglas (2004) supplemented by an additional 201 earthquakes newly evaluated by the Amateur Seismic Centre, India. We compare first the approximately 90 earthquakes for which we have both an instrumentally determined location and moment magnitude, and examine attenuation effects throughout India. We also compare the intensity-derived epicenter with the instrumental location. From empirical regressions we calculate the most probable locations and magnitudes for earthquakes in the remainder of the catalog. For those earthquakes that occur on extended sources we have modified our search procedure to seek the most probable center of a line source representing the closest edge of a subsurface dislocation to the surface. During our talk we shall present the most interesting of our findings, with comparisons between Indian and North American attenuation laws, and associate our newly derived locations with physical processes within the Indian plate and along its boundaries.
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
DE: 8199 General or miscellaneous
SC: Tectonophysics [T]
MN: 2007 Fall Meeting