A Systematic Study of the Effects of Crust and Upper Mantle Structure on Regional Seismograms
Abstract
As part of a broader effort to invert tor Eurasian crust an upper mantle structure, a study has been undertaken to-investigate the effects of structural model variations on regional synthetic seismograms. The intent of this study is to produce regional synthetic seismograms that approximately match the observed data so that the inferred structural models can be used as starting points in a formal inversion procedure. Using laterally homogeneous structural models we have systematically varied velocity-depth functions down to about 500 km depth and compared synthetic seismograms to data out to about 2000 km distance. Differential seismograms were used to infer relationships between structural parameters and the resulting seismograms. By using standard Eurasian crust and upper mantle structural models and introducing velocity randomization, it is possible to produce synthetic seismograms that show all of the regional phases complete with attendant coda. However, the synthetic seismograms show energetic P sub g and S sub n phases at distances above 1000 km that are often not present in the data. The Oh phase can be reduced by suitable upper mantle velocity profiles. The reduction of P sub g in the synthetics is more difficult which indicates that lateral scattering may be reducing P sub g amplitudes without adversely affecting L sub g.... Regional wave propagation, Seismic scattering.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1992
- Accession Number
- ADA260231
Entities
People
- Danny J. Harvey
Organizations
- University of Colorado Boulder