The Wenchuan M_w 7.9 earthquake of 12 May 2008 caused the rupture of the Longmen Shan thrust belt, which bounds the eastern margin of the Tibetan plateau, and generated a very complex surface rupture. The Beichuan–Yingxiu fault (BYF) was the main seismogenic fault and formed two distinctively different surface rupture zones separated by the Qingping and Gaochuan stepovers. Real-time kinematic (RTK) surveying of alluvial terrace sequences indicates that terraces T1-T3 and river floodplain T0 have the same vertical displacement associated with the Wenchuan earthquake. Trench excavation and optical stimulated luminescence (OSL) dating of alluvial deposits indicate that only the deformation of the Wenchuan earthquake was recorded in the Qingping stepover since at least ∼20 ka. Other deformations since ∼20 ka probably occurred in other places or did not reach the surface. This can be meaningful to analyze the completeness of paleoearthquakes in trench excavation on thrust faults.