Effects of Lateral Heterogeneities on the Propagation, Scattering, and Attenuation of the Seismic Waves and the Characterization of the Seismic Source
Abstract
The work illustrates results obtained in a broad set of applications of a technique of inverting body and surface waveform data for source mechanism and depth. The applications employ a forward model of the P waveform that includes the effects of source radiation pattern described by the zeroth order moment tensor, the effects of several near source and receiver reflections and conversions, and a teleseismic attenuation operator. This general source model has been used by many investigators during the last decade. The original contributions of the present study include investigation tradeoffs in source parameters, optimal parameterizations for extended earthquake sources, improvements in the resolution of parameters through the use of broad band data obtained from digitally recorded records, and illustration of the value of including S waves in the inversion of explosion sources, an illustrations that demonstrate that the body waveforms at some stations cannot be explained by a model of simple propagation in a radially symmetric earth. Inversions of broad band data improve the resolution of source depth, important for source discrimination, and the inclusion of S data generally reduces the non-isotropic components of the moment tensor of an explosion that would be obtained from an inversion using only P waves. Amplitude variations of P waves at some seismic stations cannot be simply explained by variations in path attenuation and indicate that multipathing and focusing and defocusing by three-dimensional structure can be important at specific sites.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1983
- Accession Number
- ADA140595
Entities
People
- K. Aki
- M. Nafi Toksöz
Organizations
- Massachusetts Institute of Technology