���ڸ̲߳������Ƶ�͹����ƻ����봨���𶼽��߶εر��������������½綨

??????????????GPS??????????????е????????????????????????λ??????????????????????????????????ε???????????????????ε????????????????λ???1.5??2 m??????δ???????????????????????????Σ?????λ????0.8 m???????δ?????в??????????λ???0.7 m?????????κ???????????????????????????Ρ????????y????????λ?????????????????????????????????????????????λ????????????

DETERMINATION OF SURFACE RUPTURE CHARACTERISTICS OF WENCHUAN EARTHQUAKE AT DUJIANGYAN SEGMENT BASED ON ELEVATION CONTROLLING POINTS AND ENGINEERING DAMAGE

The distribution of surface rupture of Wenchuan earthquake at Dujiangyan segment remains controversial for lack of direct geological evidence. We use new collected GPS survey controlling points at the Dujiangyan reservoir and postseismic resurveyed cadastral data and combine some engineering damages in the studied area to obtain coseismic vertical displacements. The results demonstrate that the Dujiangyan surface rupture segment consists of three branches: the Yingxiu part has a clear geomorphological feature with a vertical displacement of 1.5-2 m; the Longchi part ruptured the Longchi and Longxi tunnels with a vertical displacement of about 0.8 m, the Zipingpu part passed through the Zipingpu reservoir with a uplift of 0.7 m. Finally, the three rupture parts merge into one eastward segment at Hongkou town and collectively comprise the initial rupture fault segment. In addition, regional uplift is smaller than coseismic vertical displacements along the ruptured faults, suggestive of an abrupt increase at the fault zone.