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

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 ∼9cm of strike-slip displacement along a shallow subvertical fault. The earthquake was followed by at least 1year of afterslip, releasing ∼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. Key Points Seismic and aseismic slips on the southern end of the Ghazaband fault At least 1 year of afterslip with 70% of the coseismic moment release Smaller earthquakes have a higher aseismic relative to seismic moment release