Attenuation of Seismic Waves at Regional Distances
Final technical rept. 1 Oct 1978-30 Sep 1982
SAINT LOUIS UNIV MO DEPT OF EARTH AND ATMOSPHERIC SCIENCES
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This final report deals in part with the use of regional seismic crustal phases, particularly Lg, to discriminate between explosions and earthquakes, to determine mb values of explosions and earthquakes, and to estimate yields at regional distances. An mb-log yield calibration relation is developed for NTS events, and then used to estimate the yields of selected explosions at the Eat Kazakh test sites in the USSR. The report is further concerned with the attenuation of seismic surface waves at intermediate periods and how the attenuation of those waves is related to that of higher-frequency crustal phases. Significant regional variations of upper crustal Q values are found and higher frequency wave propagate more efficiently than expected on the basis of intermediate-period waves.