SEISMIC STUDIES AND EXPERIMENTAL EVALUATIONS
MICHIGAN UNIV ANN ARBOR OFFICE OF RESEARCH ADMINISTRATION
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An extensive three-year field measurement and data analyses program has been conducted to investigate the frequency and energy spectra, amplitude, and attenuation of seismic signals generated by quarry shots, underwater chemical shots, underground nuclear detonations, and earthquakes. This report summarizes this investigation a number of technical reports have been prepared which present the data in more detail. A statistical study of earthquake and nuclear explosion data revealed that particle-velocity ratios of the maximum shear-surface waves to compressional waves can be used as an aid in distinguishing between these two types of source at distances of less than 1000 km. Differences in amplitude, spectra, and energy content of seismic waves were found that could be attributed to source size, depth of source, time duration of source, geological environment at the source and recording station, and azimuthal effects around the source. Since some of the data overlap and conflict, it is difficult to positively differentiate one effect from another. Further investigations of these effects are needed to delineate the useful applications of frequency and energy data for discrimination purposes.
- Seismic Detection and Detectors