Seismic activity at the Cerro Prieto Geothermal Area (Mexico) from August 1994 to December 1995, and its relationship with tectonics and fluid exploitation
Article first published online: 7 DEC 2012
Copyright 1997 by the American Geophysical Union.
Geophysical Research Letters
Volume 24, Issue 14, pages 1807–1810, 15 July 1997
How to Cite
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 15 MAY 1997
- Manuscript Received: 15 NOV 1996
A continuous monitoring of the Cerro Prieto geothermal field was carried out from August 1994 to December 1995 to investigate the seismicity of tectonic origin and the seismicity triggered by exploitation activities. Hypocenters for 148 events were located mainly around the northern end of the Cerro Prieto fault and within the geothermal zone. The estimated focal depths range mostly from 1 to 6 km, for earthquakes with magnitudes from 0.5 to 4.6. It was difficult to distinguish between natural and triggered seismicity. We observed a single case of an earthquake for which a correlation in time and space seems plausible with a sharp increase of fluid injection in a well located at less than 1 km from the epicenter. Fault plane solutions of 26 events with magnitudes between 2.8 and 4.6 indicate right-lateral strike-slip motion for earthquakes that occur near the Cerro Prieto and Imperial faults. Inside the geothermal zone, events with normal components of motion were recorded, as expected from the extensional stress regime of the pull-apart basin laying between both faults.