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汶川地震的同震变形量及其分布是揭示汶川地震孕育机制、破裂扩展特征的重要科学依据.已有研究显示汶川地震致使龙门山中央断裂中-北段和前山断裂中段分别产生长度为240和90km的地表破裂带.在对北川县沙坝村一带地质地貌调查和广泛走访老乡,获得震前地貌、建筑物信息和照片实证的基础上,对主要的地物标志、被断错建筑物位差等进行全站仪和差分GPS实测,得到沙坝村邹家院一带最大垂直位移为(9±0.5)m,右旋位移量约为(2±0.5)m.尽管沙坝村一带地表表现为正断层,但与其他地段的同震变形一致,表现为断层西北盘上升,不存在一般正断层上盘重力下滑迹象;这些说明,(9±0.5)m的位移值应为汶川5.12地震地表最大同震垂直位移量.
Wenchuan earthquake coseismic deformation and its distribution is to reveal the Wenchuan earthquake birth mechanism, rupture expansion characteristics of the important evidence that the Wenchuan earthquake caused the central Longmen Shan central fault and the previous section of the middle of the fault were produced length 240 and 90km of surface rupture zone.Based on the survey of geology and geomorphology of Shaba Village in Beichuan County and the extensive visit to the fellow villagers and the acquisition of pre-earthquake landform, building information and photos, the paper analyzes the main landmarks, Total station and differential GPS measurements, the maximum vertical displacement of Zoujianyu in Shaba village was (9 ± 0.5) m, and the amount of right-hand displacement was about (2 ± 0.5) m. Although the surface of Shaba Village was positive But consistent with the coseismic deformations of other areas, showing the northwestern plate of the fault rising without any evidence of gravity decline of normal normal faults. These indicate that the displacement value of (9 ± 0.5) m should be the largest in the Wenchuan 5.12 Earthquake Earthquake vertical displacement.