Determination of the Slip Rate of the Lenglongling Fault in the Middle and Eastern Segments of the Qilian Mountain Active Fault Zone

Abstract

Located in the middle and eastern segments of the Qilian Mountain active fault zone,Lenglongling active fault is an important part of the Qilian Mountain fault zone in the northeastern margin of the Tibetan plateau.Based on field investigation,we found that the fault has been intensely acting since Holocene,mainly represented by left-lateral strike-slip movement with normal dip-slip,and obvious dislocated geomorphological features.The location of faults was determined by processing the high-resolution SPOT satellite digital images and large-scale aerial photos.Using the dislocated geomorphological plotting,thermoluminescence(TL) and carbon 14(14C) dating,the late Quaternary slip-rate of the Lenglongling fault was accurately determined.The average horizontal slip-rate of the Lenglongling fault has been(4.3 ± 0.7) mm / a since the late Pleistocene,and(3.9 ± 0.36) mm / a since the late Holocene.