SEISMOTECTONIC ZONATION AT NORTH-EAST IRAN

To investigate the seismotectonics of northeastern Iran, we relocated ۹۹۵ earthquakes with anuncertainty of less than ۵ kilometers and determined ۱۲۹ new focal mechanisms using the momenttensor inversion method. This comprehensive analysis revealed new faults and enhanced ourunderstanding of the mechanisms of the known faults. Notably, earthquakes in the Gorgan plain andnorth of the Doruneh fault exhibited focal depths exceeding ۲۰ kilometers. These depths wereattributed to buried thrust faults beneath the thick sedimentary cover of the South Caspian basin andcrustal thickening resulting from the northward movement of the Lut block. The spatial distribution ofthe relocated epicenters is concentrated along block borders. Stress partitioning between the Dorunehand Shurab faults was suggested based on the relocated seismicity and focal mechanisms. Integratinggeological, geodetic, and geophysical data, we propose a new seismotectonic zonation for northeastIran, comprising of ۱۹ seismic zones

کلیدواژه ها:

Multiple Relocation ، Seismotectonic Zonation ، Focal Mechanism ، Stress Partitioning