HR: 08:00h
AN: G41A-01 INVITED     [PDF]
TI: Time-Dependent Land Uplift and Subsidence in the Santa Clara Valley, California
AU: * Schmidt, D
EM: das@uoregon.edu
AF: University of Oregon, Geological Sciences, 1272 University of Oregon, Eugene, OR 97403-1272 United States
AU: B\"{u}rgmann, R
EM: burgmann@seismo.berkeley.edu
AF: University of California, Berkeley, Earth and Planetary Science, 307 McCone Hall, Berkeley, CA 94720-4767 United States
AB: We invert 115 differential interferograms derived from 47 synthetic aperture radar (SAR) scenes for a time-dependent deformation signal in the Santa Clara Valley, California. The time-dependent deformation is calculated by performing a linear inversion that solves for the incremental range change between SAR scene acquisitions. A nonlinear range-change signal is extracted from the ERS InSAR data without imposing a model of the expected deformation. In the Santa Clara valley, cumulative land uplift is observed during the period from 1992 to 2000 with a maximum uplift of 41$\pm$18 mm centered north of Sunnyvale. Uplift is also observed east of San Jose. Seasonal uplift and subsidence dominates west of the Silver Creek fault near San Jose with a maximum peak-to-trough amplitude of $\sim$35 mm. The long-term uplift is attributed to the gradual recharge of the aquifer over the 8-year period. It is assumed that the pumpage and redistribution of groundwater is responsible for the seasonal subsidence, although a direct correlation is still under investigation. The pattern of seasonal versus long-term uplift provides a qualitative constraint on the spatial and temporal characteristics of water bearing units within the aquifer. The Silver Creek fault partitions the uplift behavior of the basin, suggesting that it acts as a hydrologic barrier to ground water flow. While no tectonic creep is observed along the fault, the development of a low permeability barrier that bisects the alluvium suggests that the fault has been active since the deposition of Quaternary units.
DE: 1243 Space geodetic surveys
DE: 1803 Anthropogenic effects
DE: 1829 Groundwater hydrology
SC: Geodesy [G]
MN: 2003 Fall Meeting