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Broadband Waveform Observation of the 28 June 1991 Sierra Madre Earthquake Sequence (M_L = 5.8)

Ma, Kuo-Fong and Kanamori, Hiroo (1994) Broadband Waveform Observation of the 28 June 1991 Sierra Madre Earthquake Sequence (M_L = 5.8). Bulletin of the Seismological Society of America, 84 (6). pp. 1725-1738. ISSN 0037-1106. https://resolver.caltech.edu/CaltechAUTHORS:20140807-072115531

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Abstract

The Sierra Madre earthquake (M_I = 5.8) of 28 June 1991 occurred at a depth of about 12 km, on the Clamshell-Sawpit fault in the San Gabriel Mountains. High-quality seismograms were recorded with TERRAscope not only for the mainshock but also for the aftershocks at epicentral distances of about 16 km. We determined the focal mechanisms and seismic moments of the mainshock and 21 aftershocks by combining the waveform and first-motion data. We classified the events into five groups according to the location and waveforms recorded at PAS. Most events located within 5 km west of the mainshock are similar to the mainshock in waveform. The mechanisms thus determined are thrust mechanisms. A few events located east of the mainshock have waveforms different from the mainshock and have strike-slip mechanisms. The average Q_β values along the paths from the hypocenters of the Sierra Madre and the 3 December 1988 Pasadena earthquake (M_L = 4.9) to PAS are about 130 and 80, respectively. The stress drop of the mainshock is about 500 bars. Most of the aftershocks have stress drops between 10 and 100 bars.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://bssa.geoscienceworld.org/content/84/6/1725.abstractPublisherArticle
ORCID:
AuthorORCID
Kanamori, Hiroo0000-0001-8219-9428
Alternate Title:Broadband Waveform Observation of the 28 June 1991 Sierra Madre Earthquake Sequence (ML = 5.8)
Additional Information:© 1994, by the Seismological Society of America. Manuscript received 28 May 1993. We thank Egill Hauksson for the information on the locations, first motions, and first-motion mechanisms of the events. This work was partially supported by the USGS Grant Number 14-08-0001-G1774. Contribution Number 5415, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California.
Funders:
Funding AgencyGrant Number
USGS14-08-0001-G1774
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Division of Geological and Planetary Sciences5415
Issue or Number:6
Record Number:CaltechAUTHORS:20140807-072115531
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140807-072115531
Official Citation:Kuo-Fong Ma and Hiroo Kanamori Broadband waveform observation of the 28 June 1991 Sierra Madre earthquake sequence (ML = 5.8) Bulletin of the Seismological Society of America, December 1994, v. 84, p. 1725-1738
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:48155
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:07 Aug 2014 16:08
Last Modified:09 Mar 2020 13:18

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