Seismicity Maps of the Santa Rosa Quadrangle, California, for 1969–1995

This map set depicts several aspects of recorded seismicity that occurred from 1967 through 1995 within the Santa Rosa, California, quadrangle. The seismicity map and the related cross sections illustrate the locations, depths, and magnitudes of earthquakes. Representative focal mechanisms are also plotted to indicate the fault orientation and direction of motion on many faults. The earthquake clusters map identifies the most significant temporal clusters of earthquakes illustrating the time dependent properties of earthquake occurrence.

The Geysers geothermal area map shows the time dependent relation between the inception of geothermal power production and the occurrence of earthquake activity. In concentrations of earthquakes located beneath mapped faults, the map authors infer that the seismicity defines the subsurface orientation of these faults. Even though some concentrations of earthquakes do not underlie mapped faults, they also infer that these concentrations represent active but unnamed faults. Earthquakes also occur as isolated events beneath mapped faults and throughout the region.