Crustal deformation associated with the 1995 Hyogo-ken Nanbu earthquake, Japan derived from GPS measurements

A large M=7.2 earthquake occurred just below the western part of the Osaka-Kobe megalopolis, SW Japan on January 17, 1995. The Japanese University Consortium for GPS Research conducted extensive local GPS measurements in and around the hypocentral region to collect near-field data on co-seismic and post-seismic crustal deformation. Adopting old GPS data collected before the earthquake, co-seismic displacement vectors have been obtained at five sites. Horizontal displacements are larger than 0.4 m in the vicinity of the earthquake fault and decay steeply with distance from the fault. The horizontal deformation pattern represents a typical right-lateral slip motion along the fault. In contrast, vertical displacements are rather difficult to interpret probably because of the low precision of old GPS measurements and the complex local site condition.