Implication from the aftershocks of the 1989 Loma Prieta earthquake
- Univ. of Texas, Austin (USA)
The authors examined the P wave displacement spectra of nine aftershocks (M = 2.5{approximately}3.6) of the 1989 Loma Prieta earthquake recorded on PASSCAL/IRIS instruments to search for changes in the spectra that are indicative of heterogeneity in the source region. Temporal variations of spectral characteristics have been observed from the records of two events (No. 7 with M = 2.7 and No. 8 with M = 2.5) that occurred at an almost identical location with a time interval of 16 min and recorded at common stations. The different spectral characteristics can be attributed to the differences in the source time functions of these events. Also, the spectrum of event No. 2 (M = 2.5) that occurred near San Francisco, is substantially richer in high frequency than those from events of a comparable size in the immediate aftershock area. This could be an indication of progressive stress concentration beyond the present aftershock area.
- OSTI ID:
- 6205814
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (USA), Journal Name: Geophysical Research Letters (American Geophysical Union); (USA) Vol. 17:9; ISSN GPRLA; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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