Micro-Earthquake At Coso Geothermal Area (1992-1997)

GEOTHERMAL ENERGY

=====

Exploration Activity: Micro-Earthquake At Coso Geothermal Area (1992-1997)

Exploration Activity Details
Location	Coso Geothermal Area
Exploration Technique	Micro-Earthquake
Activity Date	1992 - 1997
Usefulness	useful
DOE-funding	Unknown

Exploration Basis

Characterize subsurface fracture patterns in the Coso geothermal reservoir by analyzing shear-wave splitting of microearthquake seismorgrams

Notes

A large number of microearthquake seismograms have been recorded by a downhole, three-component seismic network. 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 1.0 from microearthquakes recorded since March, 1992 were processed. From the delay time of split shear waves, it was estimated that the crack density in the most active geothermal reservoir area (above 3 km depth) ranges between 0.030 and 0.055.

References

• Lou, M.; Rial, J. A.   (20 January 1994) Characterization of subsurface fracture patterns in the Coso geothermal reservoir by analyzing shear-wave splitting of microearthquake seismorgrams

• Lou, M.; Rial, J.A. (1 March 1997) Characterization of geothermal reservoir crack patterns using shear-wave splitting