http://volcanoes.usgs.gov/activity/methods/insar/fact_sheet_figures.html california !!! � monitoring ground deformation from space. Interferogram showing deformation in the Los Angeles basin, from April 1998 to May 1999, draped over shaded-relief map. Based on European Remote Sensing Satellite imagery. Triangles, Global Positioning System stations. Modified from Bawden and others, 2001.