Book Description

This report presents the results of a detailed microearthquake survey of the geothermal area at Long Valley, California. High quality digital data from a dense 3-component array covering a three-month period during the summer of 1981 have been processed for locations, velocity structure, magnitudes, focal mechanisms, and source parameters. Hypocenter locations determined from this array have estimated errors of 0.5 km in epicenter and 1.0 km in depth relative to one another. Detailed hypocentral locations show two complex zones of seismicity beneath the south moat of the caldera which seems associated with the major hot spring activity within the caldera and could be part of the conduit system feeding hydrothermal waters to these hot springs. Seismic activity at Long Valley appears to be influenced by both regional tectonic stresses and local volcanotectonic activity.