Sunday, January 18, 2009

Continuous Networks

Continuous Networks: Caltech operates four separate continuous GPS networks, which combined consist of 70 permanent GPS sites. An additional 35 sites are planned to expand these networks in the near future.

* Basin and Range Geodetic Network (BARGEN): BARGEN consists of 53 GPS sites situated across the Basin and Range province of the western United States, including sites in Arizona, California, Nevada, and Utah. The network is designed in part to better understand processes involved in large-magnitude continental extension, and in part to understand strain rates surrounding the proposed Yucca Mountain nuclear waste repository. The 18 original BARGEN sites were installed in 1996, with network expansions in 1998-1999 and 2001-2002. An 18 site expansion is planned for fall and winter of 2003-2004. Learn more at the BARGEN website.
* Jalisco: Currently, a single permanent GPS site runs within the Jalisco campaign network, described above. Four additional permanent sites will be constructed in the near future.

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

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