HR: 15:45h
AN: G14A-02 INVITED     [Abstracts]
TI: Characterization of elastic and inelastic aquifer motion from satellite geodetic measurements
AU: * Bawden, G W
EM: gbawden@usgs.gov
AF: US Geological Survey, 3020 State University Drive East Modoc Hall Suite 4004, Sacramento, CA 95819 United States
AB: The production of ground water in confined aquifer systems often results in a land- surface motion that is in a gradient between two end-member models--elastic deformation and inelastic deformation--that is directly measurable by satellite-based geodetic techniques. Elastic deformation is manifested by seasonal motion associated with the pumping, but with no permanent deformation; inelastic deformation results from permanent compaction of the fine-grained units and unrecoverable subsidence of the land surface. The combination of InSAR imagery, GPS measurements, and water-levels for Salt Lake City, UT, Chino Basin, CA and the metropolitan Los Angeles-Santa Ana region, CA, are used to characterize the end-member models and a hybrid model to show how aquifers respond to ground-water pumping stresses. In Salt Lake City, ground-water pumping results in a strong seasonal motion of as much as 85 mm that is not associated with any measurable long-term subsidence signal. Conversely the Chino Basin is subsiding at a rate of 34 mm/yr from ground-water pumping, with little seasonal motion. In the Los Angeles-Santa Ana region there is both elastic and inelastic motion, with greater than 60 mm of seasonal motion associated with 20 mm/year of subsidence. The inelastic subsidence began in 1995 and has been associated with a change in ground-water pumping policy. Improved characterization of these aquifer systems, and associated subsidence, may result in more effective approaches to ground-water resource management.
DE: 1243 Space geodetic surveys
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
SC: Geodesy [G]
MN: 2005 Joint Assembly