Prehistoric seismicity-induced liquefaction along the western segment of the strike-slip Kunlun fault, northern Tibet

Abstract

Abstract The 2001 M w 7.8 Kunlun earthquake occurred in northern Tibet, and produced a 450-km-long surface rupture zone along the western segment of the strike-slip Kunlun fault. There are, however, no historic or instrumental records of large earthquakes in this fault segment. Field investigations of liquefaction structures and radiocarbon dating results reveal that at least three large earthquakes, including the 2001 earthquake, occurred in the western segment of the Kunlun fault during the past seven to nine centuries. Liquefaction structures formed in alluvial deposits composed of sand-gravel yielding 14 C ages of 679–901 yr bp are observed on the current stream channel which is sinistrally offset 75–82 m, including 3–6 m displacement produced by the 2001 event. On the basis of the field investigations and 14 C dating results, we conclude that the liquefaction structures and subsequent faulting events were caused by at least two large earthquakes of M>7 prior to the 2001 earthquake and the average recurrence interval of large earthquakes is estimated to be about 400 years in the late Holocene.