Improved Velocity Models In Western China For Two-And Three-Dimensional Finite Difference Modeling
LOS ALAMOS NATIONAL LAB NM
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In order to improve our understanding of the tectonics of western China, we are developing methods for creating improved three-dimensional 3-D lithospheric structural models for the region. Stratamodelregistered trademark, a computational toolbox for modeling fully heterogeneous rock properties in 3-D and ArcInfo, a widely accepted surface mapping routine, form the framework within which we build our models. To explore the accuracy of our new velocity structures, we compare synthetic seismograms from a full-waveform finite difference algorithm with regional data available from the IRIS-DMC for seismic events in western China. In this paper, we present seismogram modeling results from an earthquake in the Xinjiang province of western China, demonstrate improvements to previous velocity models, and describe the scheme we are using to create 2-- and 3-D velocity models for western China. On January 30, 1999, at 035107 GMT an earthquake occurred at 41.67 W, 88.46 N near the Lop Nor test site in western China. Using an anelastic finite difference code, we model the records from this event at the stations AAK, MAKZ and WMQ. Preliminary two-dimensional models were obtained for each sourcereceiver path from the Cornell Database, and these are fused with appropriate one-dimensional velocity models from published receiver function work or our own surface wave inversions. For each sourcereceiver path, the Cornell Database provides a topography profile, a depth-to-basement or basin profile, and a Moho profile. To date we have not included topography effects in our modeling.
- Geology, Geochemistry and Mineralogy