A time-series SAR observation of surface deformation at the southern end of the San Andreas Fault Zone

The San Andreas Fault (SAF) is a continental transform fault that exists as a consequence of the relative motion of the Pacific and North American Plates. Differential SAR interferometry (DInSAR) particularly with a time-series analysis is an effective tool for long-term monitoring of the SAF. Radar interferometric phase, however, contains unwanted noises originated from atmosphere as well as observation system. For studying characteristics of interferometric phase at the southern end of the SAF zone, ERS-1/2 data, acquired from 1992 to 1999, and ENVISAT data, from 2003 to the present, were utilized. Troposphere interference and orbit error were the most significant sources of errors. Since the phase noise highly correlates with topographic elevation, a simulated interferogram from topographic elevation was utilized to compensate for the tropospheric signal delay. After subtracting the simulated phase from each DInSAR interferogram, more reliable results were obtained. These results are supported by comparison with the geodetic GPS data set.