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Aftershock sequence of the 3 December 1988 Pasadena earthquake

Ma, Kuo-Fong and Kanamori, Hiroo (1991) Aftershock sequence of the 3 December 1988 Pasadena earthquake. Bulletin of the Seismological Society of America, 81 (6). pp. 2310-2319. ISSN 0037-1106.

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The Pasadena earthquake (M_L = 4.9) of 3 December 1988 occurred at a depth of 16 km, probably on the Santa Monica - Raymond fault, which is recognized as one of the most important faults in the Los Angeles basin for its potential seismic hazard. Prior to this event, no earthquake larger than magnitude 4 had been recorded since 1930 in this area. High-quality seismograms were recorded with the Pasadena very broadband (VBB) system (IRIS-TERRAscope station) not only for the mainshock but also for the aftershocks at epicentral distances of 3 to 4 km. We determined the focal mechanisms of 9 aftershocks using these data; for most of the aftershocks, the first-motion data are too sparse to determine the mechanism. We combined the first-motion data and the waveform data of P, SV, and SH waves recorded with the VBB instrument to determine the mechanism and seismic moment of nine aftershocks. The average orientations of the P and T axes of the aftershocks are consistent with the strike of the Raymond fault. The ratio of the logarithm of cumulative seismic moment of aftershocks to that of the seismic moment of the mainshock is significantly smaller than commonly observed.

Item Type:Article
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Kanamori, Hiroo0000-0001-8219-9428
Additional Information:© 1991 Seismological Society of America. Manuscript received 13 November 1990. This work was partially supported by the USGS grant 14-08-0001-G1774. Contribution no. 4943, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.
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Caltech Division of Geological and Planetary Sciences4943
Issue or Number:6
Record Number:CaltechAUTHORS:20141105-092347787
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51280
Deposited By: Tony Diaz
Deposited On:05 Nov 2014 17:34
Last Modified:09 Mar 2020 13:18

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