GPS Geodesy

Caltech is a member of UNAVCO, the NSF-sponsored university consortium that owns and operates numerous receivers utilizing the NAVSTAR Global Positioning Satellite System (GPS) for geodetic positioning. These receivers, which have a precision on the millimeter level are used for studies of tectonic deformation in California and elsewhere, both through the use of campaign-style GPS surveys of existing benchmarks, and the establishment of continuously operating GPS stations.

* Campaign Networks:
o Death Valley: The Death Valley campaign GPS network consists of 15 benchmarks designed to determine slip rates on major strike-slip faults in the Death Valley region, and to estimate the potential hazard these faults pose for the Yucca Mountain nuclear waste repository. This network was occupied annually from 1991 until 1996, and has been periodically occupied since the construction of the BARGEN continuous GPS network in the region (discussed below).
o Jalisco, Mexico: This 11 benchmark GPS network is a collaboration among la Universidad Nacional Autonoma de Mexico, Caltech, the University of Wisconsin, and the University of California at Berkeley. The network was established in 1995, in Jalisco and Colima, Mexico, in order to monitor deformation of the North America plate over the subducting Rivera plate. In October 1995, a magnitude 8 earthquake occurred in the subduction zone beneath the GPS network. The network was reoccupied annually from the earthquake until 2000, and periodically since that time. Additional benchmarks and a continuous GPS station have been added since 2000, with more continuous sites planned. More information on this network can be found here.

Courtsey - http://web.gps.caltech.edu/facilities/gps_facilities.html