November 08, 2019 Turkmanchay earthquake (Mw: 5.9) in NW Iran: an assessment of the earthquake using DInSAR time-series and field evidence

The arc-shaped Bozgush Mountains is a remarkable morphological feature bounded by active faults in northwest Iran. The southern and northern parts of the mountain belt are limited by the South and North Bozgush Fault Zones, which produced numerous destructive earthquakes in historical and instrumental periods. We employed the Sentinel-1A Differential Interferometric Synthetic Aperture Radar (DInSAR) method to map the deformation details of the November 08, 2019, Turkmanchay earthquake (Mw: 5.9) along the South Bozgush Fault Zone to understand the earthquake-triggered surface deformations and seismogenic faulting characteristics. The results of the DInSAR time-series analysis show that subsidence and uplift range from − 5 cm to + 6 cm, respectively. The total line of sight (LOS) displacement was approximately 11 cm. Interferogram fringes and deformation patterns indicate that the direction of the potential seismogenic fault is WNW-ESE. These patterns are consistent with the orientation of the South Bozgush Fault Zone, including primarily right-lateral strike-slip characteristics with reverse components. Continuous patterns of the obtained interferogram fringes indicate that surface rupture did not occur during the earthquake. Our Coulomb failure function results in preferred faults derived from geological structures, indicating that the stress rate was positive and high in several segments of the South and North Bozgush Faults, revealing that the main earthquake event might trigger those faults. The large aftershocks that occurred on the same faults supported our results, and the distribution of aftershocks in the Bozgush Mountains suggests that the WNW-ESE orientation is consistent with the orientation of segments constituting the South Bozgush Fault Zone.