Evidence for Holocene Activity on the Jiali Fault, an Active Block Boundary in the Southeastern Tibetan Plateau

Abstract

Abstract Most active block boundary faults within the Tibetan plateau have been thought of as Holocene active, and are able to produce large earthquakes. However, it is unknown whether the Jiali fault (JLF) has been seismically active in the Holocene, which currently hampers efforts to undertake meaningful seismic hazard assessments near the southeastern part of the Tibetan plateau. In this study, it is shown that the JLF has indeed ruptured during the Holocene, as evidenced from geological, paleoseismic, and radiocarbon dating investigations. Specifically, at least two surface-rupturing paleoseismic events were revealed with ages between 2160±30 yr B.P. and 2680±30 yr B.P., and prior to 2730±30 yr B.P., respectively. Combined with previous studies on the JLF, we suggest that the fault (1) can be considered an active block boundary fault and (2) accommodates crustal deformation related to the uplift of the Tibetan plateau since the late Cenozoic.