HR: 0830h
AN: S21D-0329    [PDF]
TI: Single-earthquake Location Using 3-D Vp and Vs Model - Applications in the Central USA and Taiwan Regions
AU: * Chiu, J
EM: jerchiu@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AU: Chen, H
EM: hchen@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AU: Kim, K
EM: kkim@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AU: Pujol, J
EM: jpujol@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AU: Chiu, S
EM: scchiu@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AU: Withers, M
EM: mwithers@memphis.edu
AF: The University of Memphis, Center for Earthquake Research and Information, Memphis, TN 38152 United States
AB: Traditional local earthquake location using a horizontally layered homogeneous velocity model is always limited in its resolution and reliability due to the existence of frequently overlooked 3- dimensional complexity of the real earth. Simultaneous earthquake relocation during a traditional 3-D seismic tomography has only applied to a limited set of selected earthquakes that more than 50% of earthquakes in a catalog are basically ignored. A new earthquake location program has been developed to locate every local earthquake using the best available 3-D Vp and Vs model for a region. Many modern seismic networks have provided excellent spatial coverage of seismic stations to record high-resolution earthquake data to allow the determination of high-resolution 3-D Vp and Vs velocity model for the region. Once Vp and Vs information for all 3-D grid points are available, travel time from each grid point to all seismic stations can be calculated using any available 3-D ray tracing techniques and be stored in computer files for later usage. Travel times from a trial hypocenter to the recording stations can be interpolated simply from those of the adjacent 8 grid points available in computer files without the very time consuming 3-D ray tracing. Iterations continue until the hypocenter adjustments are less than the given criteria and the travel time residual, or the difference between the observed and the calculated travel times, is a minimum. Therefore, any earthquake, no matter how small or how big it is, will be efficiently and reliably located using the 3-D velocity model. This new location program has been applied to the New Madrid seismic zone of the central USA and in various seismic zones in Taiwan region. Preliminary results in these two regions indicate that earthquake hypocenters can be reliably relocated in spite of the very significant lateral structural variations. This location program can also be applied in routine earthquake location for any seismic network in the future as long as a reliable 3-D Vp and Vs velocity model is available.
UR: http://www.ceri.memphis.edu
DE: 7200 SEISMOLOGY
DE: 7215 Earthquake parameters
DE: 7230 Seismicity and seismotectonics
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2003 Fall Meeting