Seismic Risk in Alborz: Insights from Geological Moment Rate Estimation and Fault Activity Analysis

Abstract

The Alborz mountain range in northern Iran is part of the active and seismic Alpide belt, where assessing seismic hazards is crucial due to the region’s history of large instrumental earthquakes and destructive seismic background. Moment rate estimation, which quantifies tectonic activity, offers a novel approach to understanding the energy potential of active tectonic regions. In this study, a regional perspective is employed to investigate the maximum horizontal acceleration for Tehran, the major city in Alborz, resulting from the Sorkh-e Hesar and Ghasr-e-Firuzeh faults located approximately 7.5 km southeast of Tehran. These faults have a seismic potential of Mw 6.5 and a gravity of ~0.5723. While previous studies have identified faults in northern Tehran as the greatest seismic risk, our findings suggest otherwise. The calculated geological moment was 5.18218 × 1017 Nm/y, with a seismic moment rate of 1.83375 × 1014 Nm/y, providing valuable insights into fault activity and seismic potential in the study area.