Abstract:
To investigate whether geomorphic indices can reflect the segmentation-related differences in fault activity, the Kouquan fault—a typical active normal fault located between mountain and basin on the western boundary of the Datong Basin—was selected as the study object. Based on 12.5 m resolution ALOS-PALSAR DEM data, 55 upstream drainage basins on the footwall of the fault were extracted. Several typical geomorphic indices were calculated, including basin slope, mountain front sinuosity (Smf), hypsometric integral (HI), valley-floor-width-to-height ratio (Vf), basin asymmetric factor (Af), basin elongation ratio (Re), and normalized channel steepness index (ksn). The spatial distribution of these indices across different fault segments was analyzed. Influences of non-tectonic factors such as lithology and climate were evaluated, and the results were compared with late Quaternary slip rate data. The findings reveal that the geomorphic indices primarily controlled by tectonic uplift exhibit clear spatial segmentation, with significantly higher values in the central segment than in the southern and northern segments, consistent with the spatial variation in fault slip rates. Some indices are more affected by lithological and climatic factors, showing lower tectonic sensitivity. This study confirms the effectiveness and objectivity of geomorphic indices in identifying segmentation of active faults and proposes a high-resolution, quantitative geomorphology-based approach for fault segmentation analysis.