Plate Boundary Observatory site connected via HPWREN at SDSU's Sky Oaks Field Station

Plate Boundary Observatory is the geodetic component of the NSF Earthscope initiative. It will consist of a network of about 875 continuously operating GPS receivers in the western US. These instruments are precise enough (1-2 mm/yr) to detect the constant ground motion caused by faults and volcanic activity. About 20% of the relative motion between the North American and Pacific Plates (~9-12 mm/yr) is accommodated along the San Jacinto fault zone, a system of faults that parallels the San Andreas fault to the east of Sky Oaks. The GPS measurements at Sky Oaks will play a key role in assessing the interseismic and coseismic displacements along the San Jacinto fault zone and will further help in unravelling the tectonic puzzle of the western US.

Please visit the following websites for more information about PBO's mission and operations:

http://www.earthscope.org/pbo/index.shtml
http://pbo.unavco.org/
http://www2.nature.nps.gov/geology/EarthScope/index.cfm

The station consist of a small antenna (~14 inches diameter) attached to a steel legged monument (quadrapod), an enclosure for receiver and batteries, and solar panels are mounted 25 feet away from the monument. To ensure stability, the steel legs of the monument are emplaced 4-6 feet in competent rock with a hand drill and epoxied into place. GPS data is recorded by a Trimble NetRS and routed to UNAVCO via the HPWREN. Data is freely available at UNAVCO at http://www.unavco.org/facility/data/gsac/gsac.html or SOPAC http://gsac.ucsd.edu/.

By Chris Walls, UNAVCO