University of Southern California USC Center for Geothermal Studies The USC Andrew and Erna Viterbi School of Engineering USC

Seismicity at The Geysers

Katie Boyle, Lawrence Berkeley National Laboratory

February 21, 2011 —  The Geysers Geothermal Reservoir experiences thousands of seismic events each month; some of these events are associated with recent coldwater injection and steam production within the Geysers basin.

The greatest injection volume rates have occurred in the Northern Geysers, and it is here that a flattened spheroidal region of relatively low seismic density, called the 'Doughnut Hole,' has become visible within the last 10 years. This relatively low-seismicity region is visible at depths greater than 2.7 km bsl, and is present during periods of active injection. This talk will summarize the current progress of the Doughnut Hole study, but will emphasize a thorough presentation of the dataset being used to investigate the feature--a combination of 115,000 events from both Calpine and Lawrence Berkeley National Laboratory seismic monitoring systems.

Katie Boyle is a Scientific Engineering Associate at Lawrence Berkeley National Laboratory (LBNL) and M.S. Geophysics student at Stanford University assisting with real-time seismic monitoring and data interpretation for LBNL/Department of Energy Enhanced Geothermal Systems sites. Her research interests are geomechanical modeling and source mechanism investigation related to induced seismicity, refinement of 3D seismic velocity structure through double-difference tomography, and spatial and temporal relationships between reservoir stimulation and seismicity.