资源环境科技发展态势分析平台

On 12 November 2017, a M-W = 7.3 earthquake struck near the Iranian town of Ezgeleh, at the Iran-Iraq border. This event was located within the Zagros fold and thrust belt which delimits the continental collision between the Arabian and Eurasian Plates. Despite a high seismic risk, the seismogenic behavior of the complex network of active faults is not well documented in this area due to the long recurrence interval of large earthquakes. In this study, we jointly invert interferometric synthetic aperture radar and near-field strong motions to infer a kinematic slip model of the rupture. The incorporation of these near-field observations enables a fine resolution of the kinematic rupture process. It reveals an impulsive seismic source with a strong southward rupture directivity, consistent with significant damage south of the epicenter. We also show that the slip direction does not match plate convergence, implying that some of the accumulated strain must be partitioned onto other faults.

Plain Language Summary Iran is a very seismically active region. However, the 2017 Ezgeleh earthquake of magnitude 7.3 occurred in a region where large earthquakes have not been documented for several centuries. Our knowledge of fault locations, geometries, and seismic behaviors is therefore limited in this region. We use near-field seismological and satellite geodetic data to retrieve the spatial and temporal distribution of slip occurring on the fault during the Ezgeleh earthquake. We show that the high slip rate and Southward directivity of the rupture may have worsened the damage south of the epicenter. We also observe that tectonic motion is partitioned between different types of faults. Although the Ezgeleh earthquake did release a significant part of that strain, other seismogenic faults in the region could represent an important hazard for the nearby population.