Regional tectonic dynamics in Central Iran: Unveiling the interplay of fault systems through morphotectonic and seismological analyses in the Shotori mountains

Abstract

Iran, located at the convergence of the Eurasian and Arabian tectonic plates, is a region of significant geologic and tectonic interest. This setting gives rise to complex tectonic dynamics that are crucial for understanding the seismicity and geological evolution of the area. This study provides novel insights into the tectonic dynamics of Central Iran, with a particular focus on the Shotori Mountains. Employing a combination of satellite imagery, earthquake catalog analysis, and field observations, we have studied the complex interactions among active fault systems in this part of Iran. Our investigation highlights the significant interactivity of these faults, especially at the convergence point of the Nayband strike-slip fault with the Esfandiar and Shotori thrust faults. This area is characterized by a high frequency of reverse mechanism earthquakes, primarily occurring in shallower crustal layers. A notable aspect of our findings is the identification of a distinct pattern of seismic activity linked to the interaction between different fault types. The Nayband shear zone, for instance, is critically responsible for rightlateral, oblique reverse faulting, and strike-slip events. This study also reveals a novel aspect of tectonic behavior in Central Iran: the correlation between strike-slip fault systems and their thrust terminations, influenced by the rotational dynamics of these faults. Our analysis suggests that the activation of strike-slip faults can precipitate the activation of their thrust terminations, a phenomenon particularly evident at their intersection points. This insight is crucial for understanding regional tectonic processes and could significantly impact seismic hazard assessments in Central Iran. Furthermore, the interaction between the Nayband strike-slip fault and its thrust terminations, such as the Shotori and Esfandiar faults, highlights areas of heightened tectonic activity. This study not only advances our understanding of the seismic and tectonic landscape of Central Iran but also has broader implications for regional tectonic studies and seismic risk management.