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        1 - The role of the active tectonics in geomorphic anomalies of Gorgan Rud - Gharasu basin
         Agh- Atabai  Nemati معصومه  روستائی
        The study area is located in north of eastern Alborz range. In this study, it was evaluated the pattern of neotectonic in eastern Alborz and the distribution of seismicity and geomorphic pattern of Southern Golestan province. To assess tectonic activities in 22 separat More
        The study area is located in north of eastern Alborz range. In this study, it was evaluated the pattern of neotectonic in eastern Alborz and the distribution of seismicity and geomorphic pattern of Southern Golestan province. To assess tectonic activities in 22 separated subbasins, we have analysed neotectonic indices: the stream– gradient index (SL), drainage basin asymmetry (Af), reveres symmetry of topography (T), hypsometric integral (Hi), drainage basin shape (Bs) and mountain front sinuosity (Smf). The results of the analysis is accumulated and expressed as an index of relative active tectonics (Iat), which divided into four classes from relatively low to highest tectonic activity. The high class values of tectonic activity for Iat mainly occur in the south and southwest of the Gorganrud- Gharasu drainage basin, while the rest of the study area has classes of Iat suggesting moderate to low tectonic activity. The rate of tectonic activity in this area will increase from north to south. This increase can be related to the position of peaks steam gradient index along the faults and segment faults. Also value of drainage basin asymmetry is calculated for all of the subcatechments greater or less than 50 that shows tilt for each stream toward West or East. The results of this study show that the distribution of seismicity, geomorphic and tectonic movements of studied area has been affected especially by Khazar and North Alborz faults movement and thrust fault in north of Gorgan. Areas with high tectonic activity and the high measure of tilting indicate that there may be a thrust fault, with a NNE-SSW approximate trend. On the other hand, this seismicity trend may be related to a deep and relatively young thrust splay in north of the Alborz range front. Manuscript profile
      • Open Access Article

        2 - Neotectonic zoning using morphometric indices in Lali – Gotvand area, Khuzestan
        Tayebeh Ahmadi Aziz Rahimi Hojahallah Safari Arash Barjasteh
        Quantitative assessment forms and effects of the Earth's surface and calculation of morphometry indices of rivers, river channel, and mountain fronts are the best methods for investigation of the active tectonics. The studied area is located in Dezful Embayment zone of More
        Quantitative assessment forms and effects of the Earth's surface and calculation of morphometry indices of rivers, river channel, and mountain fronts are the best methods for investigation of the active tectonics. The studied area is located in Dezful Embayment zone of the Zagros Simply Folded Belt. In this study, the tectonics and regional morphotectonics of Lali – Gotvand area are interpreted using digital elevation model. This research analyzed three indices including mountain front sinuosity (Smf), ratio of valley width to valley height (Vf) and stream length-gradient index (Sl). The morphometry indices were analyzed to determine tectonic activity according to general tectonic of Simply Folded Zagros and Dezful Embayment in Lali - Gotvand region in the north east of Khuzestan. After calculating the noted indices and information integration layers, the neotectonic zoning map were prepared as tectonic activity in 4 categories: very active, active, relatively active and non-active. According to these results, maximum tectonic activities have occurred in the North East based on stream length-gradient index, in East, North East, South East based on ratio of valley width to valley height and in North East, South East and central part based on mountain front sinuosity, respectively. The neotectonic zoning map shows the highest activity in the North, North East and Center and the lowest activity in the South of the study area. Manuscript profile
      • Open Access Article

        3 - Active Tectonics Zonation in Saveh Area, SW Tehran
        bijan abdollahi Hossein Hajialibeigi
        Geomorphic indexes can be a useful tool for investigating the impact of active tectonics and the identification of related anomalies, especially in areas that quantitative research work has been done. The study area is a part of the Central Iranian structural-sedimentar More
        Geomorphic indexes can be a useful tool for investigating the impact of active tectonics and the identification of related anomalies, especially in areas that quantitative research work has been done. The study area is a part of the Central Iranian structural-sedimentary zone, located in the Saveh area. By studying the geological and topographic maps and using digital elevation data, it was evaluated the rate of relative active tectonics of this area, using some of the geomorphic indexes such as Hi, Re ,Bs, AF, Vf, Vc, V, SL, Smf and Iat. These indexes which have been measured and compared in eight fronts and nine basins (Shur-payeinii, Lar, Bidlu, Amirabad, Shur-baleii, Eshtehard, Buin Zahra, Arab and Kharrud) resulted to present the active tectonic zonation map for the study area. The measured Hi index shows the relative maturity of all basins and the Arab basin has the most relative tectonic activity compared to other basins. The Re index shows the highest elongation for Lar, Bidlu and Kharrud basins and the least elongation for Shur-payeinii basin. The AF index shows the highest uplift for the Bidlu basin, which is located on the right side of this basin. Vf, Vc and V indexes represent the lowest rate of activity in the valleys which are located on the border between the Shur-baleii and Amirabad basins, the southern part is the Lar basin and the border between Amirabad and Bidlu basins. The Kharrud, Buin Zahra and Arab basins are the most active basins based on the SL index. The Smf index indicates the high activity for all basins. According to active tectonic zonation map, it is possible to show that on the border between the Eshtehard, Shur-baleii, Lar, Bidlu and Amirabad basins which are located in 1 class, have the highest degree of activity. These basins are affected by behavior Jaru, Gomorkan, Ipak, Takidagh, and Alishar faults. Other parts along the mountain fronts are also located in 2 class and are active. The low-lying areas (Kharrud, Buin Zahra and Arab basins) located in 3 class, have the least degree of activity. The highest rate of SL index is for Kharrud, Buin Zahra and Arab basins. This high rate resulted to the seismic and active Ipak fault. According to Smf index, Amirabad basin is the most active basins. Vf index represent the lowest rate which are located on the border between the Shur-baleii and Amirabad basins. This border is located on Jaru and Gomorkan faults. Manuscript profile