|Title||Did stresses from the Cerro Prieto Geothermal Field influence the El Mayor-Cucapah rupture sequence?|
|Publication Type||Journal Article|
|Year of Publication||2014|
|Authors||Trugman D.T, Borsa A.A, Sandwell DT|
|Journal||Geophysical Research Letters|
|Type of Article||Article|
|Keywords||anthropogenic stresses; april; baja-california; earthquake sequence; fault; fluid extraction; geothermal energy; induced seismicity; interferometry; land; mexicali valley; slip; southern california; stress triggering; subsidence; surface|
The M-w 7.2 El Mayor-Cucapah (EMC) earthquake ruptured a complex fault system in northern Baja California that was previously considered inactive. The Cerro Prieto Geothermal Field (CPGF), site of the world's second largest geothermal power plant, is located approximately 15km to the northeast of the EMC hypocenter. We investigate whether anthropogenic fluid extraction at the CPGF caused a significant perturbation to the stress field in the EMC rupture zone. We use Advanced Land Observing Satellite interferometric synthetic aperture radar data to develop a laterally heterogeneous model of fluid extraction at the CPGF and estimate that this extraction generates positive Coulomb stressing rates of order 15 kPa/yr near the EMC hypocenter, a value which exceeds the local tectonic stressing rate. Although we cannot definitively conclude that production at the CPGF triggered the EMC earthquake, its influence on the local stress field is substantial and should not be neglected in local seismic hazard assessments.
The Cerro Prieto Geothermal Field is a vital economic resource, but the influence of its anthropogenic stress field should not be ignored in future seismic hazard assessments of the Valle de Mexicali, home to more than a million people.