关键词: 嘉黎断裂, 滑动速率, 青藏高原

Abstract: The Jiali fault is one of the major faults in the southeastern Tibetan Plateau. A field investigation of this fault has been made recently. From Naqu to Jiali the fault extends roughly in N60癢 direction and consists of three segments arranged in an en echelon way. From Luoermano to Esukongma (about 40km) where the fault is the northern boundary of the Sangdi basin that extends north-south, late Quaternary surface ruptures have been found. Within this segment the creeks and gullies that cross the fault were offset and the displacements range from several meters to about 5km. The average slip rate during late Quaternary is about 15mm/a for this segment. An interesting phenomenon is that the large displacement can only be found at those places where the fault is related to the basins that extend north-south. Outside the basins, no convincing evidence has been found for late Quaternary surface ruptures and the average slip rate for the whole fault is only about 4mm/a during Quaternary. It seems that these strike-slip faults behave like a transform fault and the strike-slip motion along them are a consequence of east-west extension that creates the north-south graben systems rather than the vice versa.

Key words: Jiali fault, Slip rate, Tibetan Plateau