Insight into the 2017–2019 Lurestan arc seismic sequence (Zagros, Iran); complex earthquake interaction in the basement and sediments

SUMMARY Despite its high-seismogenic potential, the details of seismogenic processes Zagros Simply Folded Belt (SFB) remains debated. Three large earthquakes (Mw 7.3, 5.9 and 6.3) struck in Lurestan arc SFB 2017 2018. The sequence was recorded by seismic stations at regional, teleseismic distances. Coseismic surface displacements, measured Sentinel-1A/B satellites, provide additional data a unique opportunity to study these detail. Here, we complement previous studies coseismic slip distribution 12 November Mw 7.3 Ezgeleh earthquake detailed analysis aftershocks, analysed rupture process two interrelated (25 August 2018 Tazehabad 25 6.3 Sarpol-e Zahab earthquakes). We model displacements obtained from Interferometric Synthetic Aperture Radar (InSAR) measurements records. conduct non-linear probabilistic optimizations based on joint InSAR obtain finite-fault earthquakes. were followed sustained aftershock activity, with 133 aftershocks exceeding Mn 4.0 until 30 December 2019. rely permanent networks Iran Iraq relocate ?700 3 + events estimate moment tensor solutions for 85 down 4.0. has been considered activate low-angle (?17°) dextral-thrust fault depth 10–20 km. However, most have shallow centroid depths (8–12 km). interpretation finite source models, hypocentral location indicate that ruptured different strike-slip structures, providing evidence activation sinistral dextral faults, respectively. deformation is seismically accommodated complex system involving both thrust faults. Knowledge about characteristics important understanding crustal shortening, faulting hazard risk assessment this region.