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Analysis of the Microseismicity of the Salton Buttes Region

G. McStroul and G. Simila
California State University, Northridge, CA, [email protected], [email protected]

For the Salton Trough region, we are analyzing the microseismicity from the SCSN database of the region around the Salton Buttes, which are five rhyolite domes at the southern end of the Salton Sea and near the Brawley seismic zone. The microseismicity is characterized by small magnitude events (M=1-2), except for the 2005 earthquake swarm (max M=5.1). The 2005 focal mechanisms indicated NW-SE strike-slip faulting. We will be participating in the January 2010 Salton Trough Seismic Project, funded by NSF (Margins/Earthscope) and the USGS. In the Salton Trough, the 20-22 km thick crust is composed entirely of new material added by magmatism from below and Colorado River sedimentation from above. The adopted model of magmatic addition to the crust is from A. Schmitt and J. Vazquez (2006), where mafic magma reaches neutral buoyancy in the lower to middle crust. In Fall 2009, we will install five digital seismographs to supplement the existing SCSN network for a more detailed study related to subsurface structures. Then in January 2010, we will participate in the main north-south USGS seismic reflection/refraction line.

AAPG Search and Discovery Article #90088©2009 Pacific Section Meeting, Ventura, California, May 3-5, 2009