HR: 15:25h
AN: T23F-08    [Abstracts]
TI: Computational Improvements for Deriving a 3-D Shear-Wave Model for the Tarim Basin, China, Using Multiple Geophysical Observations
AU: * Lucero, C
EM: xian98@nmt.edu
AF: New Mexico Institute of Mining and Technology, Mathematics Department, Socorro, NM 87801, United States
AU: Maceira, M
EM: mmaceira@lanl.gov
AF: Los Alamos National Laboratory, EES-11, M.S. D-408, Los Alamos, NM 87545, United States
AU: Rowe, C
EM: char@lanl.gov
AF: Los Alamos National Laboratory, EES-11, M.S. D-408, Los Alamos, NM 87545, United States
AU: Steck, L
EM: lsteck@lanl.gov
AF: New Mexico Institute of Mining and Technology, Mathematics Department, Socorro, NM 87801, United States
AU: Borchers, B
EM: borchers@nmt.edu
AF: New Mexico Institute of Mining and Technology, Mathematics Department, Socorro, NM 87801, United States
AB: We derive a 3-dimensional Vs model for the Tarim Basin, China, using surface wave dispersion, teleseismic receiver functions, gravity and body-wave travel times. High-resolution Rayleigh wave slowness maps provide 23 group velocity dispersion curves in the period range between 8 and 100 s for a grid of locations across central Asia. Receiver functions for 38 stations and body wave travel times for 4315 seismic events are included. GRACE satellite gravity observations constrain simultaneous information from neighboring map cells and layers to properly account for density contributions to seismic velocity. The combined data sets produce a model fitting diverse geophysical parameters, and allow us to constrain the model in places where one parameter may be poorly represented; however, the diversity of parameters and size of the problem pose difficulties regarding stability and limited computing resources. We use an interative, LSQR conjugate gradient solver in lieu of singular value decomposition (SVD). LSQR is ideal for large, overdetermined sparse systems. Or optimized inversion requires 0.05% of the memory for SVD and runs ~1000 times faster, permitting multiple runs within a tractable time frame. Preliminary results agree with the SVD findings, indicating very low upper crust and high upper mantle shear velocities beneath the Tarim basin; these values exhibit variations between the eastern and western parts of the Tarim.
DE: 7218 Lithosphere (1236)
DE: 7270 Tomography (6982, 8180)
DE: 7290 Computational seismology
DE: 8180 Tomography (6982, 7270)
DE: 9320 Asia
SC: Tectonophysics [T]
MN: 2007 Fall Meeting