HR: 0800h
AN: S51A-0142    [Abstracts]
TI: Characterizing Local Seismicity of the Bhutan Himalaya: An Analysis of Earthquakes Recorded With a Temporary Seismic Network During 2002-2003
AU: * Gee, V L
EM: vgee@geo.utep.edu
AF: University of Texas at El Paso, Department of Geological Sciences 500 University Avenue, El Paso, TX 79968 United States
AU: Velasco, A A
EM: velasco@geo.utep.edu
AF: University of Texas at El Paso, Department of Geological Sciences 500 University Avenue, El Paso, TX 79968 United States
AU: Rowe, C
EM: char@lanl.gov
AF: Los Alamos National Lab, EES -11 MS D408, Los Alamos, NM 87545 United States
AB: The University of Texas at El Paso (UTEP) operated a temporary seismic network in the Kingdom of Bhutan between January 2002 and March 2003. This network consisted of five three-component, broadband instruments. Our network, in combination with regional stations, detected approximately 2,100 teleseismic, regional and local events, $\sim$900 of which do not appear in the global NEIC catalog. We reviewed these 900 events and manually timed P- and S-wave arrivals. Using a subset of $\sim$200 events which occurred within Bhutan, a preliminary 1-D local velocity model was developed using the program VELEST. We further evaluated these events by quality weighting each arrival and testing several velocity models for the region. We relocated events with the program HYPOELLIPSE, using a suite of velocity models obtained from other regional studies, as well as our own preliminary 1-D model, to investigate the sensitivity of hypocenter locations and their associated uncertainties to variations in the available models. Using the data output from HYPOELLIPSE, we set specific criteria for developing our highest quality events. These criteria include azimuthal gap, number of stations recording the event, number of phases, and the size of the error ellipses. Based on our criteria, hypocenter locations were obtained and show generally scattered locations; however, they exhibit a concentration in southwestern Bhutan where there appears to be a quasi-linear cluster of events. We evaluate the apparent seismicity concentrations in terms of waveform similarity and the existence of doublet or multiplet / repeating events within our catalogue and present these findings, along with general seismicity parameters for the catalog.
UR: http://www.geo.utep.edu/pub/vgee
DE: 7230 Seismicity and seismotectonics
DE: 7205 Continental crust (1242)
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting