The NEES Garner Valley Downhole Array (GVDA) is a ground motion research site in a seismically active region in Southern California. It is located in a narrow valley within the Peninsular Ranges Batholith 23 km east of Hemet and 20km southwest of Palm Springs and is just 7 km from the San Jacinto fault and 35 km from the San Andreas fault.
The site has been thoroughly characterized through recent borehole geotechnical tests and in other studies over the last ten years. Instrumentation of the GVDA site began in 1989. See the Geotechnical/Geophysical Specifications tab below for more details.
An array of accelerometers and pore-pressure transducers capture the ground and sub-surface motion due to local, regional and even teleseismic events. For full details of the sites sensors see the Instrumentation tab below.
In addition to the main station ground-motion instrumentation, a one-story soil-foundation-structure-interaction (SFSI) structure has been constructed at the site for the study of dynamic response of this structure during earthquakes, and some 3km to the west of the main site at the edge of the valley (at the Lake Hemet dam) another small group of sensors (GVAR) record motions of the exposed bedrock outcrop.