| Abstract: | Event record sections, which are constructed by plotting seismograms from many closely spaced earthquakes recorded on a few stations, show multiple free-surface reflections (PP, PPP, PPPP) of the P wave in the Imperial Valley. The relative timing of these arrivals is used to estimate the strength of the P-wave velocity gradient within the upper 5 km of the sediment layer. Consistent with previous studies, a velocity model with a value of 1.8 km/sec at the surface increasing linearly to 5.8 km/sec at a depth of 5.5 km fits the data well. The relative amplitudes of the P and PP arrivals are used to estimate the source depth for the aftershock distributions of the Elmore Ranch and Superstition Hills main shocks. Although the depth determination has large uncertainties, both the Elmore Ranch and Superstition Hills aftershock sequencs appear to have similar depth distribution in the range of 4 to 10 km. -Author |
| Genre: | Article |
| ProdID: | 70016951 |
| Citation Author: | Mori, J. |
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| Citation End Page: | 523 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Bulletin - Seismological Society of America |
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| Citation Number Of Pages: | 16 |
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| Citation Search Results Text: | Estimates of velocity structure and source depth using multiple P waves from aftershocks of the 1987 Elmore Ranch and Superstition Hills, California, earthquakes; 1991; Article; Journal; Bulletin - Seismological Society of America; Mori, J. |
| Citation Start Page: | 508 |
| Citation Volume: | 81 |
| Citation Year: | 1991 |
| Type: | citation/reference |
| Text: | Estimates of velocity structure and source depth using multiple P waves from aftershocks of the 1987 Elmore Ranch and Superstition Hills, California, earthquakes; 1991; Article; Journal; Bulletin - Seismological Society of America; Mori, J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 1 Jan 1991 00:00 -0600 |
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