Collection and Analysis of Seismic Wave Propagation Data
(final Report) August 1966. Prepared for the Geophysics Division, Air Force Office of Scientific Research, Arlington, Virginia
Description:... The report summarizes four years of theoretical and applied research on propagation of seismic waves and techniques for analyzing data. Coherent optical processing techniques for analyzing seismic data were investigated and evaluated. Linear mode filtering, employing Fourier techniques, of seismic data was developed; it permits separating linear from elliptical ground motion. Frequency-analysis techniques involving optical, analog computer, digital computer, and active electronic filters were developed and evaluated. Radiation patterns from the regions of cylindrical and elliptical sources were investigated. Source motion was studied, using data from short-distance compressional waves. Theoretical studies of the scattering caused when an incident wave encounters an elliptical obstacle were conducted; both near-field and far-field effects were determined. A preliminary analysis of long-range refraction profiles obtained between Lake Superior and the Atlantic Ocean disclosed that anomalies in travel time and amplitude occur across the Michigan Basin and Appalachian Mountains. The anomaly across the Basin is substantiated by recordings of NTS events. A seismic-well monitoring station of intermediate depth was designed and put into operation; it reduces by a factor of ten microseismic background noise at frequencies above 1 cps. A processor to convert large-aperture seismic array (LASA) digital information into analog form was designed and partially constructed. (Author).
Show description