Lg Excitation, Attenuation and Source Spectral Scaling In Central Asia and China.
Final rept. 1 Nov 93-31 Oct 95,
SAINT LOUIS UNIV MO DEPT OF EARTH AND ATMOSPHERIC SCIENCES
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The nonlinear inverse method of Xie 1993 is applied to analyze Lg spectra from 21 underground nuclear explosions and 52 shallow 5-33 km earthquakes in central Eurasia where, for numerous paths, Lg Q and Lg coda Q at 1 Hz are found to be very similar. The logarithm of Lg seismic moment Mo values correlate linearly with body wave magnitude Mb, with slopes of slightly greater than 1.0. For the same Mo values, the Mb values for earthquakes tend to be systematically lower than those for explosions. For both explosions and earthquakes, Mo scale with fcaa, with fc being Lg corner frequency and a being closer to 4 than to 3. For explosions, the estimated Mo, fc values are dependent on whether the explosion or earthquake source model is used. At any given Mo level, the fc value estimated for an explosion with the earthquake source model tends to be higher than that for an earthquake. This tendency appears to be opposite to that observed at the NTS, and maybe used as an explosion discriminant for central Eurasia.
- Seismic Detection and Detectors