Deformation and fault parameters of the 2005 Qeshm earthquake in Iran revisited: A Bayesian simulated annealing approach applied to the inversion of space geodetic data

The estimation of earthquake source parameters using an earth surface displacement field in an elastic half-space leads to a complex nonlinear inverse problem that classic inverse methods are unable to solve. Global optimization methods such as simulated annealing are a good replacement for such problems. Simulated annealing is analogous to thermodynamic annealing where, under certain conditions, the chaotic motions of atoms in a melt can settle to form a crystal with minimal energy. Following this, the unknown model parameters are analogous to the molecules of a molten solid whose chaotic motion gradually ceases during cooling, and the state corresponding to the global minimum of the cost function becomes highly probable at a very low temperatures. parameters of the 2005 Qeshm earthquakes have already been estimated using various studies, including seismicity, the earthʹs surface deformation field, and rupture characteristics. Each of these studies proposes different mechanisms for the earthquakes. In this study, source parameters of the 2005 Qeshm earthquake and its main aftershock are determined with their precision by applying simulated annealing optimization in a Bayesian framework using a coseismal deformation field derived from Envisat radar interferometry. The results agree with surface ruptures and the proposed activation of the Qeshm and a NW–SE faults during main shock and main aftershock. This estimate indicates a reverse-slip of 88 ± 11 cm on the Qeshm fault and 38 ± 12 cm of strike–slip on the NW–SE fault.