News Release Address: Email:
Placer Hall dacox@usgs.gov
U.S. Department of the Interior
6000 J Street
U.S. Geological Survey Sacramento, CA 95819
Release Contact: Phone:
Upon Receipt Dale Alan Cox 916-997-4209
Faxed February 24, 2003
Also available on the Internet at:
http://www.usgs.gov/public/press/public_affairs/press_releases/index.html
The earth has subsided as much as four inches in parts of the Mojave Desert in southern California, according to U.S. Geological Survey (USGS) scientists. Using the satellite mapping process known as interferometric synthetic aperture radar (InSAR), scientists have detected large earth surface depressions near the agricultural areas of Lucerne Valley, El Mirage, Lockhart, and Newberry Springs in the southwestern portion of the Mojave Desert. The subsidence occurred between 1992 and 1999 and is linked to declining water levels.
"The magnitude of subsidence in some of the areas is significant," said Michelle Sneed, USGS scientist and lead author of the study, "The compaction of the aquifer systems in these areas may be permanent."
The USGS study, in cooperation with the Mojave Water Agency, found that land subsidence was linked to water-level declines of more than 100 feet between the 1950s and the 1990s. Land subsidence can disrupt surface drainage; reduce aquifer storage; cause earth fissures; and damage wells, building, roads, and utility infrastructure. "Earth fissures several feet wide and deep have been observed in Lucerne Valley," Sneed said. The USGS reports that continued monitoring of some areas of the Mojave Desert is warranted because ground-water levels continue to decline, and pumping-induced land subsidence, documented by this study, likely will increase.
The U.S. Geological Survey report, "Detection and Measurement of Land Subsidence Using Interferometric Synthetic Aperture Radar and Global Positioning System, San Bernardino County, Mojave Desert, California" by Michelle Sneed, Marti E. Ikehara, S.V. Stork, Falk Amelung, and D.L. Galloway, can be found on the Internet at:
http://water.usgs.gov/pubs/wri/wri034015/
The USGS serves the nation by providing reliable scientific information to: describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.
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