Ground subsidence in Tucson, Arizona, monitored by time-series analysis using multi-sensor InSAR datasets from 1993 to 2011

The groundwater in Tucson, Arizona, is a major source for water supply to human residential areas and agricultural use, and the groundwater extraction causes ground deformation responding to aquifer-system compaction. Using multi-temporal C-band and L-band SAR images from ERS/ENVISAT and ALOS PALSAR satellites, we mapped the ground displacement in Tucson. The InSAR-derived ground displacement based on small baseline subset technique (SBAS) is compared to compaction from extensometers, land subsidence from GPS survey, and groundwater elevation at wells. Tucson is characterized by slow and relatively small subsidence over areas with upper stratigraphic till early 2000s when the groundwater had been extremely depleted and by uplifts in areas where the water level has been recently recovered into the slight increase of water table because of recharge into the aquifer. Our multi-sensor SBAS InSAR-derived vertical displacements enabled to monitor the temporal variability in the spatial extent and magnitude of the ground deformation, suggesting that recent ground subsidence is slowing down and the ground motion in places is stable. Our results can provide scientific basis for sound management of ground water pumping and recharge over the study area.