Application of small baseline subsets D-InSAR technology to estimate the time series land deformation and aquifer storage coefficients of Los Angeles area

The Los Angeles area is a tectonically active region with a combination of natural and anthropogenic deformations, such as, fault related tectonics, oil and groundwater recharge and discharge. In this paper, we process a dataset of 19 descending ENVISAT ASAR images acquired between September 2003 and August 2009 over Los Angeles and generate 71 differential interferograms, which are characterized by perpendicular baseline smaller than 300m and time interval less than 3 years. Based on Small Baseline Subsets (SBAS) D InSAR technique, we estimate the time series land deformation of this area. With the additional GPS and groundwater data, we further estimate the aquifer storage coefficients. The results show that: (1) a couple of deformation evident regions can be easily identified from the interferogram, including the aquifers compaction related subsidence area such as Pasadena basin ('-' 2.5 cm a): San Gabriel valley (∼- 2 cm a): San Bernardino basin (∼ - 2.5 cm a): Pomona Ontario basin (∼- 4 cm a) and Santa Ma basin (∼- 2.5 cm a): and the oil extraction related area such as Santa Fe Springs (∼ - 1 cm a): Wilmington (∼- 1 cm a) and so on; (2) InSAR derived and LOS projected GPS deformation velocity show a very good consistency, with a RMS difference of 0.39 cm a; (3) InSAR deformation time series and groundwater level variations are in good agreement. Based on the theory of poroelasticity, we calculate the elastic and inelastic skelet al storage coefficient and analyze the deformation mechanisms of aquifer system.