Seismotectonic Characterization of the Khoy region (NW Iran and Eastern Türkiye) based on earthquake focal mechanisms and seismic catalogs

The Khoy and surrounding regions, located in northern Iran and eastern Türkiye, have intensive seismicity and complex tectonics due to the Eurasia and Arabian collision zone. This study evaluates present-day and short-term seismic hazard conditions through the analysis of selected seismotectonic parameters, including Coulomb stress changes, distribution patterns of the b-parameter estimated using the Gutenberg–Richter law, earthquake probabilities, and return periods. Based on the spatial distribution of earthquake clustering, fault kinematic solutions ( M _W ≥4.0), and the local fault characteristics, the study region is subdivided into three distinct sub-regions. The data for analysis are collected from KOERI (Türkiye), IIEES (Iran), and the CSEM-EMSC data portal, searching the period from 1905 to 2026, despite the inaccurate and inhomogeneous catalogues. Our results reveal that the triple junction composed of the Başkale Fault, Saray Fault, and Tasuj Fault within the western part of the study area exhibits potentially high seismicity with the lower b -value (~0.6) and maximum positive stress values (0.1 in bars). Toward the eastern part of the research area, the positive Coulomb stress values transfer north of the North Tabriz Fault and west of the Ahar Fault. Additionally, the lowest b -values (~0.3) are observed west of the North Tabriz Fault and in the vicinity of the Khoja Fault. Notably, the findings provide evidence for relatively high potential in the region north of Urmieh Lake. Finally, the results of our study will provide important insights into intermediate-term seismic hazard assessment.