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Geomorphic parameters, which reflect the migration of drainage divide responses, are widely used to assess tectonic activity. There have been several large earthquakes in the history of the Hetao Basin, within which the Sertengshan Piedmont Fault is important. This study highlights certain references for regional seismic risk assessment. Few studies have been conducted on the Sertengshan area from the perspective of geomorphic parameters. In this paper, ksn, HI, and Vf were obtained to indicate the tectonic activity in the Sertengshan area, and χ and Gilbert metrics were extracted to explore the state of the drainage basin. The results show that the tectonic activity varies spatially and is strong in the western part of the southern Sertengshan region and the northern part corresponding to the turning point of the fault. Most of the Sertengshan area is in the prime and old stages of geomorphological evolution, whereas some areas are in the juvenile stage. The old stage was mainly concentrated in the northern region, and the southern part was younger than the northern region. Overall, the Sertengshan area is tectonically active and affected by the activity of the Sertengshan Piedmont Fault. The western part of the divide migrated northwest, while the central and eastern parts tended to move southward. We suggest that the divide migration is influenced by tectonic activity and tends to move towards the direction of lower tectonic activity. [ABSTRACT FROM AUTHOR]

The temporal slip behavior of a fault from displaced landforms when there are no chronological data remains poorly understood. The southern segment of the Xiaojiang fault zone (XJFZ) plays an important role in accommodating the lateral extrusion of the SE Tibetan plateau. However, there are few reports on the evolution of the offset landforms and slip behavior of the fault due to the dense vegetation in the region. Here, offset landforms along the Jianshui fault (JSF) in the southern segment of the XJFZ are systematically interpreted and measured using high-resolution satellite imagery, field investigations, and airborne lidar. The risers on the right banks of three stream channels feature similar left-lateral offset characteristics near the town of Dongshanzhai. The left-lateral offsets consist of multiple inflections produced by seismic events, and the offset of each event is similar. These inflections are distributed downstream in a stair-stepped manner. The newly formed inflections are located close to the fault, and the earlier formed ones are eroded by flowing water and migrate downstream. The difference between the amount of downstream erosion of two adjacent inflections varies. Assuming the stream's long-term erosion rate remains steady, the estimated time intervals between seismic events are different. Combined with the cumulative offset probability density calculation for 92 offsets, the JSF is considered to show a nonperiodic characteristic earthquake recurrence pattern. We also propose a multistage offset evolution model of the stream channel riser. This provides a new way to analyze the seismic recurrence pattern of the fault over a relative time scale. [ABSTRACT FROM AUTHOR]