Spatial–temporal surface deformation of Los Angeles over 2003–2007 from weighted least squares DInSAR

The spatial–temporal evolution of surface displacement of Los Angeles area over 2003–2007 is measured with weighted least squares (WLS) small baseline (SB) DInSAR technique. 32 small baseline interferograms are generated from 18 SAR images acquired by the ENVISAT satellite and separated into two independent subsets. An additional interferogram with a longer baseline but good interferometric quality is used to link the two subsets. A time series of displacements with their corresponding standard deviations (STD) are derived from the WLS DInSAR solution by considering the interferometric displacement variances when determining the weighting scheme.Both the long-term trends and the seasonal variations of the displacements in the area are determined in the study and validated with GPS measurements from a number of stations of the Southern California Integrated GPS Network (SCIGN). The mean line-of-sight (LOS) displacement velocity map shows up to 3 cm/year of ground motion and up to 10 cm of accumulated displacements in Santa Fe Springs and −8 cm in Pomona over 2003–2007. Seasonal variations are identified in Santa Ana basin, the San Gabriel valley and the Lytle Creek basin, respectively.

► We propose a weighted least squares DInSAR approach for studying ground deformation. ► It eliminates the need of using SVD in the conventional SBAS and considers the noise of interferograms. ► Motion of up to 3 cm/year and active seasonal variations are found in Los Angeles.