Crustal deformation during 6 years spanning the Mw = 7.2 1995 Nuweiba earthquake, analyzed by Interferometric Synthetic Aperture Radar

Baer, G., Shamir, G., Sandwell, D., Bock, Y. 2001. Crustal deformation during 6 years spanning the M w = 7.2 1995 Nuweiba earthquake, analyzed by Interferometric Synthetic Aperture Radar. Isr. J. Earth Sci. 50: 9–22. The November 22, 1995, M w = 7.2 Nuweiba earthquake occurred along one of the left-stepping segments of the Dead Sea Transform in the Gulf of Elat (Aqaba). We examine the surface deformation patterns in the region by Interferometric Synthetic Aperture Radar (InSAR) for the period 1993 to 1999, which includes the end of one seismic cycle and the beginning of the next. Because the main rupture was under water, ERS coverage is limited to distances of approximately 5 km or more away from the rupture. Pre-earthquake interferograms do not show any detectable deformation along the Gulf. Coseismic interferograms show deformation at distances of up to 50 km from the main rupture, with the highest fringe rate (strain) NW of the rupture termination. Coseismic phase gradient maps show triggered slip along faults parallel to the main rupture (sinistral or normal with the Gulf side down) along the western shore of the Gulf, and in a belt of extensional faults along the eastern shore, striking at angles of about 30° to the major rupture. Postseismic deformation is observed only in a time window of up to 6 months following the mainshock. It was concentrated in the region of the high coseismic strain, and seems to be related to the M L > 4.5 aftershocks in the respective time window.