Detection of Crustal Deformation of the Northern Pakistan Earthquake by Satellite Data

A large-scale earthquake with a magnitude of 7.6 occurred on October 8, 2005 in the northern part of Pakistan. The Geographical Survey Institute carried out various analyses to clarify the crustal deformation accompanied with the earthquake in detail with the data from the satellites. We mapped the crustal deformation spatially with Synthetic Aperture Radar data from the European Space Agency’s ENVISAT, and found that the newly deformed area occupies a 90-kilometer-long northwest-southeast trending strip. Heavily damaged area north of Muzaffarabad has the maximum deformation up to 6-meter uplift as observed by the satellite. There are known active faults stretching to the northwest and southeast near the epicenter, which reveal some uplift (on the northeastern side) and dextral (right-lateral) strike-slip activities. The detected crustal deformation was along these active faults and all observations were consistent with previously known directions of past fault movements. Model calculations also showed that the faults slipped a maximum of about nine meters. In addition, analysis using other high-resolution images from IKONOS and SPOT-5 satellites showed that slope failures occurred along the active faults and were concentrated on the northeastern side.