9416338 Bock This project will investigate the time series of positions from the Permanent Global Positioning System (GPS) Geodetic Array prior to and after the Northridge earthquake of January 17, 1994 focussing on the anomalous strain events detected at the Jet Propulsion Laboratory and Ranchos Palos Verdes sites several months before the earthquake. The signals will be analyzed by data stacking procedures to see if they are real indicators of anomalous strain variations or artifacts of the initial analysis. If real, these signals may be preseismic indicators and this will be tested by comparison with other available data and earthquake models. In addition, improved techniques will be developed for densification and rapid response of GPS measurements in the San Fernando Valley and Los Angeles Basin. The results of this study will have major implications for earthquake hazards mitigation using space geodetic techniques in blind thrust environments such as the San Fernando Valley and Los Angeles Basin.
