The eastern margin of the Tibetan Plateau is marked by the Longmen Shan thrust belt (LSTB), which is dominated by thrust faults and thrust-related fold structures that is home to the 2008 Mw 7.9 thrusting-type Wenchuan earthquake. Although previous works demonstrated that the seismogenic fault for the earthquake changed coseismic slip sense from thrust-dominated slip in the central and southeastern segments of the LSTB to right-lateral strike-slip-dominated displacement along the Qingchuan fault (northeastern segment of the LSTB), the related structures and current activity of the Qingchuan fault remains unclear. Topographic analyses of 0.5-m-resolution WorldView imagery and Digital Elevation Model (DEM) data, field investigations and structural analysis of the fault zone reveal that: i) stream channels and late Pleistocene–Holocene terrace risers and alluvial fans are systematically offset dextrally along the Qingchuan fau ii) foliations developed in the fault zone indicate a right-lateral strike-slip-dominated displacement; and iii) geological evidence and seismic data show that the Qingchuan fault is currently active as the main seismogenic fault dominated by a right-lateral strike-slip with an average slip rate of ca. 3–5 mm/yr. Our results demonstrate that the spatial change in slip sense along the LSTB from thrust-dominated in the central and southwestern sectors to right-lateral strike-slip-dominated in the northeastern sector is mainly caused by a change in the orientation of fault geometry from NE–SW to ENE-WSW along the LSTB.
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