DETECTION OF AQUIFER SYSTEM COMPACTION AND LAND SUBSIDENCE USING INTERFEROMETRIC SYNTHETIC-APERTURE RADAR, ANTELOPE VALLEY, MOJAVE-DESERT, CALIFORNIA

Interferometric synthetic aperture radar (InSAR) has great potential t o detect and quantify land subsidence caused by aquifer system compact ion. InSAR maps with high spatial detail and resolution of range displ acement (+/-10 mm in change of land surface elevation) were developed for a groundwater basin (similar to 10(3) km(2)) in Antelope Valley, C alifornia, using radar data collected from the ERS-1. satellite. These data allow comprehensive comparison between recent (1993-1995) subsid ence patterns and those detected historically (1926-1992) by more trad itional methods. The changed subsidence patterns are generally compati ble with recent shifts in land and water use. The InSAR-detected patte rns are generally consistent with predictions based on a coupled model of groundwater flow and aquifer system compaction. The minor inconsis tencies may reflect our imperfect knowledge of the distribution and pr operties of compressible sediments. When used in conjunction with coin cident measurements of groundwater levels and other geologic informati on, InSAR data may be useful for constraining parameter estimates in s imulations of aquifer system compaction.