A New Southern California GPS Network to Advance the Study of Earthquakes -- The SCIGN "Unveiling" Event

Press Release Fact Sheet (available from the USGS as a PDF) High-Resolution Images: Block model, maps, station photos, etc. SCEC Instanet News: SCIGN Unveiling Event Full Transcripts of Unveiling Event Speeches Summary On July 6, 2001, earthquake scientists unveiled the Southern California Integrated GPS Network (SCIGN), a new type of ground motion monitoring network. Unlike other instrument networks that record shaking, SCIGN tracks the slow motion of the Earth's plates by using the Global Positioning System (GPS) -- a constellation of satellites, originally designed for military navigation, that are used to determine precise locations on the ground. With SCIGN, the link between the motions of the plates that make up the Earth's crust and the resulting earthquakes is now being observed by an array of GPS stations operating in southern California and Baja California -- one of the world's most seismically active and highly populated areas. The 250th SCIGN station was installed on July 2, 2001. Using SCIGN data to measure deformation of the Earth's crust, which can occur as movement on faults or as slow distortion of the ground, scientists can determine how strain builds up slowly over time before being released suddenly during earthquakes. The accumulated strain is directly related to earthquake potential, and measurement of it contributes to earthquake hazard assessments that help motivate people to prepare for earthquakes. "We have in southern California over half of the nation's earthquake risk, and we are applying GPS technology in new ways to assess this risk," said SCIGN chairman Ken Hudnut of the U.S. Geological Survey. >Read more about SCIGN in the press release and fact sheet. You can also download a SCEC Newsletter about SCIGN (1 MB PDF version).

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