Temporal principal component analysis and synthetic aperture radar interference analysis of the spatial and temporal evolution of ground subsidence in the Los Angeles area

The temporal principal component analysis (TPCA) method in the field of geology can extract the temporal and spatial features of spatial-temporal data, and the ground subsidence in the Los Angeles area has typical temporal and spatial features. Based on the ground subsidence data of the Los Angeles area from 2016 to 2019 obtained by small baseline set (SBAS)-InSAR technology, TPCA and wavelet analysis were used to analyze the spatial and temporal evolution characteristics of ground subsidence in the Los Angeles area. Several results were found. First, the first principal component obtained by TPCA analysis reflected the spatial and temporal evolution characteristics of ground subsidence at that time series stage. Second, after wavelet analysis and the temporal trends of the eigenvectors of the second and third principal components, it can be seen that the second and third principal components mainly correspond to the periodic deformation and that the maximum amplitude of the periodic oscillation is 10 mm. Third, the correlation analysis of the eigenvectors of groundwater level, rainfall, and the fourth principal component reveals that there is a time phase delay between deformation and groundwater level change and rainfall.