Non-double-couple earthquake mechanisms at the Geysers geothermal area, California

Geophysical Research Letters
By: , and 

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Abstract

Inverting P- and S-wave polarities and P:SH amplitude ratios using linear programming methods suggests that about 20% of earthquakes at The Geysers geothermal area have significantly non-double-couple focal mechanisms, with explosive volumetric components as large as 33% of the seismic moment. This conclusion contrasts with those of earlier studies, which interpreted data in terms of double couples. The non-double-couple mechanisms are consistent with combined shear and tensile faulting, possibly caused by industrial water injection. Implosive mechanisms, which might be expected because of rapid steam withdrawal, have not been found. Significant compensated-linear-vector-dipole (CLVD) components in some mechanisms may indicate rapid fluid flow accompanying crack opening. Copyright 1996 by the American Geophysical Union.

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Publication type Article
Publication Subtype Journal Article
Title Non-double-couple earthquake mechanisms at the Geysers geothermal area, California
Series title Geophysical Research Letters
DOI 10.1029/96GL00590
Volume 23
Issue 8
Year Published 1996
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Hazards Program
Description 4 p.
First page 877
Last page 880
Country United States
State California
Other Geospatial Geysers Geothermal Area
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