Morphotectonic Analysis Using Geomorphic Indices of the Gumal Valley Basin, Northern Iraq

Geomorphological indicators are important and capable of decoding the responses of landforms to active deformation processes, and are particularly useful in tectonic studies for analyzing, interpreting, monitoring, and understanding changes in landforms because they can be used to quickly assess regional areas. Gumal valley basin is located in northern Iraq and is situated over two different tectonic zones, the High-Folded Zone and Low-Folded Zone. This study examined the status of tectonic activity through quantitative analyses using equations of geomorphological indicators of tectonic activity. A GIS program based on a digital elevation model (DEM) with a resolution of 12.5 m is used to derive sub-basins for the Gumal valley basin, where the number of derived sub-basins in the study area is 38. Five indices are selected for analysis: Stream length gradient index (SL), asymmetry factor (Af), ratio of the valley floor and valley height (Vf), Transverse Topographic Symmetry (T), and mountain front sinuosity (Smf). The results of each index are classified into three categories, and by calculating the arithmetic mean of these indices, an index of relative tectonic activity is obtained. The active tectonics index (IAT) results have been classified into four classes of too high to a little tectonic activity; this reveals that there is no area classified as class 1 (of very high activity). However, 21%, 55%, and 24% of the basin are categorized as classes 2 (of high activity), 3 (of moderate activity), and 4 (of low activity), respectively. Most of the basins are of high and moderate categories, and these basins are located in the High-Folded Zone.