Interdisciplinary determination of active magmatic processes of the Socorro Magma body, central New Mexico

Abstract

In this project we integrate complementary analyses of GPS and passive seismic data to explore the mechanisms of magma inflation and crustal deformation caused by the Socorro Magma Body (SMB), a mid-crustal magma body residing at 19 km depth, which is responsible for as much as 45% of earthquakes above magnitude 2.5 in New Mexico. Previous studies involving active-source seismic refraction have contributed to determining the geometry of the SMB. New work using campaign geodetic measurements and InSAR interferometry during 1992-1999 has suggested that average uplift is occurring at 2-3 mm/year. Two new continuously telemetered GPS stations have been installed near two seismic stations in the Sevilleta National Wildlife Refuge located at 34°12'N 106°45'W and 34°15'N 106°58'W. Co-location of these stations will help illuminate the temporal relationship between deformation and seismicity associated with the SMB at time scale that have not previously been examined. We are developing a new catalog of seismicity occurring between 33°30'N to 35°N and 106°15'W to 107°30'W. It is a combination of arrival time data from larger events from the years 1996-2004 and waveform data for all locatable events, with preliminary data quality thresholds requiring a minimum of four recognizable arrivals recorded between September, 2004 and the present. This combined catalog of at least 500 events will be relocated using waveform cross-correlation and travel-time differential methods to sharpen our image of the seismogenic sources associated with inflation-induced seismicity.