Remote Sensing Image Characteristics and Seismic Hazard of the Baiganhu Fault on the South Side of the Central Segment of the Altyn Tagh Fault

[Objective]Accurately defining the spatial distribution and scale of active faults is fundamental for for analyzing regional tectonic deformation and assessing seismic hazards. [Methods]Using multi-source high-resolution satellite imagery, this study systematically interprets the faulted geomorphic features of the sinistral strike-slip Baiganhu Fault, located south of the central segment of the Altyn Tagh Fault. [Result]The results show that the fault is approximately 247 km long with a general NEE trend. It has been intensely active since the Late Quaternary, as evidenced by extensively developed faulted geomorphic markers such as offset alluvial fans, transtensional cracks, pressure ridges (mole tracks), offset gullies, and sag ponds. Based on its geometric structure and spatial distribution, the Baiganhu Fault can be divided into western, central, and eastern segments. The central segment preserves a ~50 km long surface rupture zone with an average coseismic horizontal offset of 4.8 m, indicating the occurrence of a past strong earthquake with M_W 7.4±0.3. Statistical analysis of 99 left-laterally offset gullies shows an average horizontal offset of 4.3-4.8 m for the most recent event. [Conclusions]While a throughgoing rupture of the entire Baiganhu Fault could generate an earthquake of M_W 7.8±0.3, the ~5 km wide stepover it forms with the Altyn Tagh Fault is unlikely to fully arrest throughgoing rupture propagation. [Significance]This implies a potential for cascading rupture between the two faults. Therefore, the seismic hazard posed by the Baiganhu Fault warrants significant attention, and regional seismic hazard assessments must fully consider the possibility of its cascading rupture with the Altyn Tagh Fault.