A New Regional 3-D Velocity Model for Asia from the Joint Inversion of P-Wave Travel Times and Surface-Wave Dispersion Data
Abstract
Accurate travel-time predictions for regional seismic phases are essential for locating small seismic events with the accuracy needed for nuclear monitoring decisions. Travel times calculated through a three-dimensional (3-D) Earth model have the best chance of achieving acceptable prediction errors, if the model is constrained by sufficient data. With this motivation, we have developed a self-consistent 3-D P and S velocity model of the crust and upper mantle in a large region of southern and central Asia to a depth of approximately 400 km. Our new model is the result of a nonlinear, joint body-wave/surface-wave inversion method applied to Pn travel times collected from the Engdahl, van der Hilst, and Buland (EHB) bulletin and group-velocity measurements provided by the University of Colorado and Lawrence Livermore National Laboratory. Consistency between the P and S velocities is achieved by imposing bounds on Poisson's ratio and by invoking a regularization constraint that correlates variations in P and S velocity from an initial model. We have tested our new model for its predictive capabilities using data from a large database of ground-truth events, which were held out from the joint inversion. The tests include the relocation of the ground-truth events, using data sets of Pn-only and Pn/Sn arrivals, and the direct comparison of predicted Pn and Sn travel times to the ground-truth observations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 2008
- Accession Number
- ADA487601
Entities
People
- Delaine T. Reiter
- William L. Rodi