DISCRIMINATION OF GEOPHYSICAL PHENOMENA IN SATELLITE RADAR INTERFEROGRAMS

Various geophysical phenomena are recorded in the interference pattern s formed by differencing two synthetic aperture radar (SAR) images. Th e fringes generated by the topographic relief can be removed using a d igital elevation model (DEM). The remaining fringes map the change in satellite-to-ground range which occurred between the acquisition times of the two images. By comparing different pairs of images spanning di fferent intervals of time, it is possible to discriminate between geop hysical signal and interferometric artifact. Here we apply this pair-w ise logic to the area around the 1992 Landers, California earthquake u sing SAR images acquired by the ERS-1 satellite. The range varies with time as a constant, step, impulsive, or sloping function. Examples of each type include a DEM error, an aftershock, two atmospheric perturb ations, and postseismic afterslip, respectively. Their signatures are identified and separated using the pair-wise logic.