Coseismic deformation and source model of the 12 November 2017 M_W 7.3 Kermanshah Earthquake (Iran–Iraq border) investigated through DInSAR measurements

ABSTRACT

A large earthquake with a magnitude of M_W 7.3 struck the border of Iran and Iraq at the province of Kermanshah, Iran. In our study, coseismic deformation and source model of the 12 November 2017 Kermanshah Earthquake are investigated using ALOS-2 ScanSAR and Sentinel-1A/B TOPSAR Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques. Geodetic inversion has been performed to constrain source parameters and invert slip distribution on the fault plane. The optimised source model from joint inversion shows a blind reverse fault with a relatively large right-lateral component, striking 353.5° NNW-SSE and dipping 16.3° NE. The maximum slip is up to 3.8 m at 12–14 km depth and the inferred seismic moment is 1.01 × 10²⁰ Nm, corresponding to M_W 7.3, consistent with seismological solutions. The high-resolution optical images from SuperView-1 satellite suggest that most of the linear surface features mapped by DInSAR measurements are landslides or surface cracks triggered by the earthquake. Coulomb stress changes on the source fault indicating consistency between aftershock distribution and high loaded stress zones. Based on the stress change on neighbouring active faults around this area, the Kermanshah Earthquake has brought two segments of the Zagros Mountain Front Fault (MFF), MFF-1 and MFF-2, 0.5–3.1 MPa and 0.5–1.96 MPa closer to failure, respectively, suggesting the risk of future earthquakes. Recent major aftershocks (M_W≥ 5.0) could probably ease the seismic hazard on MFF-2, but the risk of earthquakes on MFF-2 is still increasing.

Acknowledgments

The ALOS-2 ScanSAR data are provided by the Japan Aerospace Exploration Agency (JAXA) and the Sentinel-1 SAR data are provided by the European Space Agency (ESA). The information about aftershocks is provided by Iranian Seismological Centre (IRSC). The details on active faults are provided by the International Institute of Earthquake Engineering and Seismology (IIEES) in Iran. We thank Space View for making SuperView-1 postseismic images publicly available. The first author gratefully acknowledges financial support from the China Scholarship Council (CSC). This research was partly supported under the Australian Research Council’s Discovery funding scheme (project number DP130101694) and JAXA PI investigation project 1419 – Automated interferometric analysis of L-band SAR satellite data for operational earthquake and volcano monitoring.

Authors’ contribution

Linin Ge and Graciela Isabel Metternicht proposed the topic and evaluated the accuracy of the results, Jianming Kuang performed the entire analysis and wrote the manuscript, Alex Hay-Man Ng helped with the DInSAR analysis, Hua Wang helped with the modelling analysis, and Mehdi Zare and Farnaz Kamranzad helped with data collection and manuscript preparation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Australian Research Council [DP130101694];China Scholarship Council [201608440352].