Geomorphic Processes and Active Tectonics Evaluation in Diyala River Basin (Iraq-Iran) Using the Hypsometric Curve Moment Statistical Analysis Method and Its Density Function

Abstract

The main work of this study is to provide geomorphic indices and active tectonics in the Diyala River Basin of Iraq and Iran. The hypsometric curve (HC) analysis method and its statistical moments were adopted to use for the assessment. These methods have been widely used for the assessment of geomorphic processes and active tectonics in many areas in the world showing promising results. A total of 26 watersheds of the Diyala River is analyzed. The result shows that 3 curve-types such as "straight- shape", "S- shape", and concave were found; with the concave curve being the dominant and widely distributed in the west side and in the east of the southwestern side of the study area. The hypsometric integral (HI) values are rather small with the largest value is 0.53 and the smallest one is 0.16. Moment’s statistical analysis of the hypsometric curve, skewness, kurtosis, skewness, and density kurtosis functions are showed in great values, which increased in the south direction of the Diyala river Basin. Based on that, the recent active tectonics (uplift) in the study area is generally moderately; however, they are also not completely homogeneous and can be distinguished by different levels. The northeastern side is being lifted higher than the southwestern side. The northern part is being lifted larger than the southern part. In the region, the uplift activities were increased gradually in the Pliocene- Quaternary and could have been continued at present time. The current geomorphic processes are mainly headward erosion in the upstream.