Title:

Characterization of Subsurface Fracture Patterns in the COSO Geothermal Reservoir by Analyzing Shear-Wave Splitting of Microearthquake Seismograms

Authors:

M. Lou, J.A Rial

Geo Location:

Coso, California

Conference:

Stanford Geothermal Workshop

Year:

1994

Session:

Introduction/Sciences

Language:

English

File Size:

485KB

View File:

Abstract:

A large number of microearthquake seismograms have been recorded by a downhole, three-component seismic network deployed around the COSO, California geothermal reservoir. Shear-wave splitting induced by the alignment of cracks in the reservoir has been widely observed in the recordings. Over 100 events with body wave magnitude greater than 1 .O from microearthquakes recorded since March of 1992. have been processed. The results show that most events with paths within the critical angle that defines the shear-wave window, display clear shear-wave splitting, and the fast shear waves have predominant polarization directions for most stations. The rose diagrams of fast shear-wave particle motion suggest that there are three predominant fracture strikes (or directions of maximum horizontal stresses) in the COSO geothermal field: N 4Oo-68E, N 0?-29E, and N 2 9 - 3 9 W, which are consistent with photographically or magnetically mapped alignments on the surface. From the delay time of split shear waves, we estimate that the crack density in the most active geothermal reservoir area (above 3.00km depth) ranges between 0.030 and 0.055. values commonly found in other hydrocarbon or geothermal reservoirs.


ec2-35-171-159-141.compute-1.amazonaws.com, you have accessed 0 records today.

Press the Back button in your browser, or search again.

Copyright 1994, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.


Attend the nwxt Stanford Geothermal Workshop, click here for details.

Accessed by: ec2-35-171-159-141.compute-1.amazonaws.com (35.171.159.141)
Accessed: Thursday 28th of March 2024 11:42:34 AM