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GEOREF RECORD

Seismicity in the Clear Lake area, California, 1975-1983

Donna Eberhart-Phillips
Seismicity in the Clear Lake area, California, 1975-1983 (in Late Quaternary climate, tectonism, and sedimentation in Clear Lake, Northern California Coast Ranges, John D. Sims (editor))
Special Paper - Geological Society of America (1988) 214: 195-206

Abstract

Earthquake locations for the time period March 1975 through March 1983 indicate diffuse seismicity in the Clear Lake area, with the area to the southeast of the lake having the highest level of activity. Swarms lasting two days, with events of magnitude greater than or equal to 3.5, have been observed in the Konocti Bay fault zone. In contrast, almost no microearthquake activity is associated with the Collayomi fault zone. A 10-kilometer-wide northeast-southwest-trending zone of seismicity is apparent although there is no known corresponding geologic feature. Earthquake depths in the Clear Lake region are shallower than in the surrounding major right-lateral fault zones. Focal mechanism solutions show predominant strike-slip with significant normal dip-slip movement. The maximum and minimum compressive stress orientations, north-northeast and east-southeast, respectively, are consistent with the San Andreas right-lateral transform boundary region. However, the component of extensional stress illustrated by normal fault-plane solutions and the shallowness of seismicity may be related to an inferred nearby crustal partial melt body. (See also W89-10137) (Author 's abstract)


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 214
Title: Seismicity in the Clear Lake area, California, 1975-1983
Title: Late Quaternary climate, tectonism, and sedimentation in Clear Lake, Northern California Coast Ranges
Author(s): Eberhart-Phillips, Donna
Author(s): Sims, John D.editor
Affiliation: U. S. Geol. Surv., Menlo Park, CA, United States
Affiliation: U. S. Geol. Surv., Menlo Park, CA, United States
Pages: 195-206
Published: 1988
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2214-4
References: 19
Accession Number: 1988-068799
Categories: Seismology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables, sketch maps
N32°30'00" - N42°00'00", W124°30'00" - W114°15'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from USGS product, Selected Water Resources Abstracts, Reston, VA, United States
Update Code: 1988
Program Name: USGSOPNon-USGS publications with USGS authors
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