Active Tectonics Assessment Using Geomorphic and Drainage Indices in the Sertengshan, Hetao Basin, China

Abstract

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.