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U.S. Department of Energy
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Discrimination studies using short-period P waves at upper mantle distances. Annual report, January 1986-January 1987

Technical Report ·
OSTI ID:6774923
This report reviews the properties of seismograms recorded at upper mantle distances in stable continental region such as northwest Eurasia in order to examine how well current models predict the general behavior of the observations and to see how much unmodeled energy, or noise, is present. In general The proposed models for the region predict the major arrivals observed in the data. For explosions, there are few distinct arrivals that are not associated with some predicted upper mantle phase. However, noise levels (or code amplitudes), are large, since each arrival has a code associated with it that adds constructively at the receiver. Use predicted coda amplitudes, in a Pearce algorithm to discriminate on the basis of focal mechanism. Given good azimuthal coverage of an event (e.g., 3 of 4 quadrants), the observed complexity of the explosion seismograms is incompatible with that predicted for earthquakes at depth using simple models for the reflection of the depth phases pP and sP. These results are similar to previous findings that considered teleseismic data.
Research Organization:
Sierra Geophysics, Inc., Kirkland, WA (USA)
OSTI ID:
6774923
Report Number(s):
AD-A-195468/4/XAB; SGI-R-88-136
Country of Publication:
United States
Language:
English