论文部分内容阅读
2008年5月12日发生的汶川地震是由青藏高原东部龙门山断裂的活动所导致。震后的调查表明,北川县城以北的断裂段破裂了约90km。在北川县城以北,不同地点沿地震地表破裂所展现的地表变形差异很大,可能反映了断裂附近地表特性的变化。文章主要从5个典型地点来阐述5种代表性的地表变形模式。前两个地点,在北川县城以北几公里,反映了近地表基岩中的一种变形和从基岩向松散堆积物过渡区的一种变形模式。与此两种断裂陡坎变形不同,中间的两个点则阐述了褶皱陡坎,它们反映了2008年地震中断裂断错在地表以下终止的不同情形。最后一个点位于汶川地震地表破裂的北端,可能代表了当地表破裂结束时地表变形的模式。在北川以北段地表破裂上典型地点的详细测量的基础上,通过归纳野外获得的地表变形资料,构建出汶川地震地表破裂北川以北段的基本变形模型。
The Wenchuan earthquake on May 12, 2008 was caused by the activity of the Longmen Shan fault in the eastern Tibetan Plateau. A survey after the earthquake showed that the fracture zone north of Beichuan County ruptured for about 90km. In the north of Beichuan County, there are great differences in surface deformation along the surface rupture caused by the earthquake, which may reflect the change of the surface characteristics near the fault. The article mainly elaborates five kinds of representative surface deformation modes from five typical locations. The first two locations, a few kilometers north of Beichuan County, reflect a deformation pattern of near-surface bedrock deformation and transition from bedrock to loose deposits. Different from the deformation of the two scarps, two points in the middle explain the fold scarps, which reflect the different situations of fault rupture below the surface in the 2008 earthquake. The last point, located at the northern end of the surface rupture of the Wenchuan earthquake, may represent the surface deformation pattern at the end of the local surface rupture. Based on the detailed measurement of the typical locations of the surface rupture in the north section of Beichuan, the basic deformation model of the north section of the Beichuan area caused by the Wenchuan earthquake was constructed by summarizing the surface deformation data obtained in the field.