BASIC RESEARCH IN CRUSTAL STUDIES
Abstract
The work falls into four tasks: (1) single-layer models; (2) multilayer models; (3) models with layer thickness variation; and (4) experimental studies using field data. The single-layer studies included theoretical investigation of normal and leaking modes, studies of the practical aspects of frequency-wavenumber analysis and investigation of mode separation by multichannel filtering. Theoretical and analog model investigations for two layers over a half-space showed the difficulty in directly observing an intermediate velocity layer using frequencies of 0.5 cps or less. Analog model investigations of a model having a dipping M-discontinuity showed a wide range of phase velocities for ray events, as predicted. Experimental studies of field data showed the usefulness of velocity filtering as an interpretive aid. Correlation statistics for small events showed that only about 50 percent of the energy arriving between the first arrival and surface waves is predictable. For events at small distance (delta < 30 km), Rayleigh-mode dispersion curves were measured. These suggested low near-surface velocities extending to a depth of 1/2-km. It was found that receiving arrays inline with the shot are necessary for adequate dispersion measurements.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 1965
- Accession Number
- AD0628385
Entities
People
- Milo M. Backus
- Stanley J. Laster
Organizations
- Texas Instruments