What is SCIGN?

The Southern California Integrated GPS Network (SCIGN) is a dense array of GPS receivers in the Los Angeles Basin and surrounding region. The network continuously records minute movement of the Earth's crust, measuring millimeter-scale deformation caused by tectonic plate motions.

The idea of a continuously recording GPS network was conceived following the 1994 Northridge earthquake. Data collected before the earthquake using campaign-style technique, in which a site is occupied for a couple of days every few months to a year, suggested potential hazard on a fault system that included the Northridge rupture. Although this style of data collection provided useful information, it did not provide continuous monitoring of crustal movement, which includes earthquakes.

After the Northridge earthquake, scientists began to realize the value of using GPS as a tool to monitor the small-scale movement of the crust, which could yield clues about where and when future earthquakes may occur. This earthquake was the impetus for proposing a continuously recording GPS network in the region.

Following the earthquake, 40 permanent stations were installed throughout the LA Basin and surrounding area to monitor the crustal movement in the region. JPL joined its efforts with the Southern California Earthquake Center (SCEC), the US Geological Survey (USGS), and the Scripps Institution of Oceanography (SIO) in order to install the array. The 40-station array was a test network, and the full network proposed for SCIGN would include 250 stations throughout the Southern California region.

In 1997, the W. M. Keck Foundation dontated $6 million in order to install the remainder of the stations in the network. Since then, 23 additional stations have been installed, many at high schools,colleges, and universities. Over 100 sites have been approved, and are being installed. The complete250-station SCIGN network should be installed and operational sometime in 1999.

The main objectives of the network are to monitor crustal motions to estimate earthquake hazard potentional, to identify active blind thrust faults like the one that caused the Northridge earthquake, to measure strain in the region in order to understand the mechanics of faults, and to measure deformation of the crust and changes in regional strain caused by earthquakes.

What is SCIGN? Who runs it? Who has access? What happens to SCIGN data? How are the SCIGN data used? More about SCIGN