Coseismic and postseismic deformation due to the 2007 M5.5 Ghazaband fault earthquake, Balochistan, Pakistan

摘要

Time series analysis of interferometric synthetic aperture radar data reveals coseismic and postseismic surface displacements associated with the 2007 M5.5 earthquake along the southern Ghazaband fault, a major but little studied fault in Pakistan. Modeling indicates that the coseismic surface deformation was caused by similar to 9cm of strike-slip displacement along a shallow subvertical fault. The earthquake was followed by at least 1year of afterslip, releasing similar to 70% of the moment of the main event, equivalent to a M5.4 earthquake. This high aseismic relative to the seismic moment release is consistent with previous observations for moderate earthquakes (M<6) and suggests that smaller earthquakes are associated with a higher aseismic relative to seismic moment release than larger earthquakes.