Assessment of active tectonic by using geomorphic indices in Dezful- Andimeshk basin

Aims and Backgrounds: Almost no area in the world can be found that has not been affected by tectonic processes. The morpho-tectonic indices of the basin are used to investigate the active tectonics. Morphometry can be defined as the quantitative measurement of the shape of the Earth's landscape that using these quantitative measurements can identify areas with active tectonics. The purpose of this study was to investigate the Active tectonic in Dezful- Andimeshk basin using five geomorphological indices of the Drainage Asymmetry Factor (Af), Relative relief (Bh), Form factor (Ff), Hypsometric integral and curve (Hi), and Stream gradient index (SL). With this research, it is possible to find out the active processes in Dezful-Andimeshk basin and the damage from natural disasters such as floods and earthquakes can be partially prevented. Methodology: The present study is an applied one and has used quantitative calculations. GIS software and digital elevation map (DEM) with resolution of 30 m were used to calculate the indices. For each index, the zoning map in the study area was plotted and and each of these indices was divided into five categories of very high, high, medium, low and very low in terms of tectonic activity. Finally, by averaging the whole set of indices, a final index called relative active tectonics index (Iat) was calculated and the study area was divided into four categories of very high, high, medium and low tectonic activity. Findings In the sub basins corresponding to Dowragh, Mountain Front Fault and Parts of the Labrian, Ramhormoz and Balarud, The measured indices show high values due to the high tectonic activity of the area. Conclusion: The results of this study show that recent relative tectonic activity in Dezful-Andimeshk basin is high and very high due to the impact of the faults on the area.