Influence of faults on landslide formation and distribution: Insights from the Hanwang Fault Zone in the Qinling-Daba Mountains, China

Faults contribute significantly to the formation and distribution of landslides, especially in the highly faulted Qinling-Daba mountain region. Yet, evidence of the long-term and regional dependency influence of active faults on landslides is limited. In particular, in-depth knowledge is still lacking regarding their specific mechanisms, influence range, and detailed interaction processes. This study focuses on Hanwang Town, a region in the Qinling-Daba Mountains with extensively developed fault structures and frequent geological hazards. Detailed field survey data, photogrammetry, UAV technology, point cloud analysis software, laboratory experiments, and SBAS-InSAR technology were utilized to quantify the relationship between the Hanwang Fault Zone and distributed landslides with various formation patterns. The results reveal that the Hanwang Fault Zone primarily affects regional geological hazards by influencing the geometric and mechanical properties of rock masses and changes in topography. Specifically, the critical threshold distance of the Hanwang Fault damage zone is approximately 2.2 ± 0.3 km. Geological hazards are linearly distributed along the fault zone. The joint density of rock masses shows a strong negative correlation with their distance from the fault zone. The mechanical properties of rock masses rapidly decline due to fragmentation, affecting slope stability. Furthermore, the application of SBAS-InSAR technology has enabled the identification of differential uplift and subsidence rates in the vicinity of the fault zone, which has been identified as contributing factors in the formation of hydrogeological structures that are conducive to the occurrence of geological hazards. This study not only reveals the dynamic influence of the Hanwang Fault Zone but also provides an in-depth analysis of the development characteristics and damage mechanisms of geological hazards under the control of the fault zone based on typical cases. The findings open new perspectives for understanding the complex relationship between fault zones and geological hazards, providing scientific and technical support for disaster risk management and sustainable development strategies.