Geological features and hazard effects of the Wuli active fault system on the northern Qinghai-Tibet Plateau

located in the Wuli Mountains ,the Wuli active fault system is an important regional active tec-tonic system of the northern Tibetan Plateau.It consists mainly of 17active faults of different scales and natures.Most of the active faults are left-lateral oblique-slip ones and part of them are left-lateral strike-slip ones.According to field observations ,it is estimated that the left-lateral strike-slip rate and vertical slip rate of some typical active faults are1.2-3.5mm /a and0.5-3.5mm /a respectively.Five100-400m wide surface fracture zones,many bead-like ice hummock swarms and some migrating ice hummocks are developed along the Wuli active fault system.High-density surface rupturing produced by structural fissures and surface domal deformation caused by migrating ice hummocks are main geological hazards affecting the safety of the Golmud-Lhasa railway,highway and pipeline.