Elmira Mosadeghzadeh; Mohammad Khalaj
Abstract
Morphotectonics is a science that determines the effect of active tectonics by using geomorphic indicators as a measurement and quantitative description of landforms and landscapes. Morphotectonics provides quantitative measurements that can be used to identify areas with active tectonics. In this study, ...
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Morphotectonics is a science that determines the effect of active tectonics by using geomorphic indicators as a measurement and quantitative description of landforms and landscapes. Morphotectonics provides quantitative measurements that can be used to identify areas with active tectonics. In this study, using quantitative morphometric indices obtained from morphotectonic studies, a part of Central Alborz (Marzanebad and Taleghan cities) has been studied and five hierarchical anomaly indices (a∆), branching index (R), Basin shape (Ff), drainage density (Dd) and roughness coefficient (Bh) were calculated in 19 drainage sub-basins. In these areas, each of these indices is classified into five groups: very high, high, medium, low and very low, and finally the relative active tectonic index (Iat) is obtained. Based on the results of this study, the Caspian, North Alborz, Dozdben and Kandovan and North Taleghan fault basins are in very high and high groups, which indicates the impact of these faults on the active tectonics of the region. Due to these high values, it is expected that the seismic risk of the region will increase due to fault rupture. The density of recent earthquakes in the region confirms this.
Hasan Alizadeh; Mohammad Khalaj
Abstract
In the present study, to analyze the earthquake risk of Isfahan, seismic studies and seismic hazard studies have been performed. In seismic studies of tectonics and seismic hazards of each region, it is necessary to study the active faults of that region with a radius of about 300 km, so in this study, ...
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In the present study, to analyze the earthquake risk of Isfahan, seismic studies and seismic hazard studies have been performed. In seismic studies of tectonics and seismic hazards of each region, it is necessary to study the active faults of that region with a radius of about 300 km, so in this study, active faults in Isfahan province were also studied. According to the obtained results, the north-south stress trend of Isfahan province due to the activity of straight-slip faults and the northwest-southeast stress trend indicate the reactivation of the rocky faults. The southern parts of the province, including Kolah Ghazi and Pirbakran faults, and part of Khansar fault, as well as the area of Najafabad fault in the northwest and part of Baharestan and Dehaq faults show the most activity in the region. The southern, southeastern and southwestern parts of Isfahan province have moderate activity compared to other parts of the province. According to this research, the city of Isfahan and especially its northern regions are in low risk and low activity in terms of earthquake risk. However, due to the density of identified faults, the southern parts of Isfahan are in the range of moderate seismic risk. Therefore, according to the seismic characteristics of the region and the seismic potential of active faults, necessary measures should be taken to strengthen buildings and structures in urban policies and programs.
