The present study examines the tectonics of the Fahlian River Basin, situated within the Zagros Mountains in Fars Province. The TecDEM adjunct function in Matlab 2008 software was employed to calculate and ascertain the indices. To examine the region in terms of tectonic activity, five indices were employed, including the basin hypsometric curve index (Hi), basin asymmetry (AF), valley floor width to height ratio (VF), mountain front sinuosity (Smf), and river longitudinal slope (SL). The results of the valley floor width-to-height ratio (VF) index indicate the presence of moderate to high tectonic activity in various regions of the study area. The V-shaped valleys observed in the southern channel are indicative of this index. In the central region, the valleys are V-shaped but exhibit evidence of slight erosion. The value of the Smf index in the Fahlian Basin was 1.42, indicating low levels of tectonic activity. As the Smf index approaches one, tectonic activity increases. A sudden shift in the isobase map may indicate the presence of faults or significant geological changes in the region. Such a sudden change is evident in the northeastern region of the Fahlian Basin, which may be attributed to the presence of unidentified faults. Given the absence of faults evident in the geological map of the region and the uniformity of the trend in the geological formations, the relative uplift rate map of the studied area illustrates the disparity in uplift rate across different parts of the region. The southern regions of the Fahlian Basin exhibit the lowest uplift value, while the northeastern regions demonstrate the highest uplift values. These findings align with those observed in the isobase map.