The north boundary fault zone of the Amdo basin is consists of 3~4 southeast-dipping normal faults (Fig.10) and extends for ~50km northeastward (Wu et al., 2004, 2005). It dislocates a variety of bedrocks and Late Pleistocene-Holocene alluvial and fluvial fans and forms multi-phase faceted-spurs and different levels of fault scarps. It experiences Ms 4.0-5.0 earthquakes and controls linear-distributed low temperature hotsprings. Vertical displacements along the north boundary fault in Late Pleistocene-Holocene are 45m, 23m, 16m, 7~9m, and 1.6m from earlier stage to present. Cliffs along triangular spurs reach 80m, 160-180m and 300-500m from lower to upper levels. The vertical slip-rate average of north boundary fault of Amdo basin is estimated as 0.24mm/a in Quaternary and 0.46-0.67mm/a in Late Pleistocene-Holocene.

Fig.10 Features and strikes of boundary faults of Ando basin