地学前缘 ›› 2010, Vol. 17 ›› Issue (5): 43-52.

• 论文 • 上一篇    下一篇

汶川Ms 8.0级地震地表破裂带近断层水平缩短量研究

王虎, 冉勇康, 陈立春, 陈文山, 杨志成, 徐锡伟   

  1. 1中国地震局 地质研究所 国家地震活断层研究中心, 北京 100029
    2台湾大学 地质科学系, 中国 台北 106
  • 收稿日期:2010-06-25 修回日期:2010-08-01 出版日期:2010-09-15 发布日期:2010-05-22
  • 通信作者: The study of nearfault horizontal shortening of the surface rupture in Wenchuan Ms 80 earthquake
  • 作者简介:王虎(1983—),男,博士,主要从事活动构造研究。Email: wanghu9905@126.com
  • 基金资助:

    国家自然科学基金项目(40821160550,40872130);中国地震局汶川80级地震科学考察项目

The study of nearfault horizontal shortening of the surface rupture in Wenchuan Ms 80 earthquake.

  1. 1National Center for Active Fault Studies, Institute of Geology, China Earthquake Administration, Beijing 100029, China
    2Department of Geosciences, Taiwan University, Taipei 106, China
  • Received:2010-06-25 Revised:2010-08-01 Online:2010-09-15 Published:2010-05-22

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摘要：

2008年5月12日四川汶川发生Ms 80特大地震后,地表同震位移量已有了大量的详细调查和研究,然而对于近断层同震水平缩短量的研究却相对较少。笔者在中央断裂、前山断裂以及北西向分支断裂上选择合适地点进行大量探槽开挖,获得了近断层同震水平缩短量的分布情况为:中央断裂清平镇(28 m)、擂鼓镇(32 m)、平通镇(13 m),前山断裂白鹿镇(25 m)、九龙镇(14 m)、汉旺镇(06 m)。文中进一步在中央断裂和小鱼洞分支断裂地表破裂带上开挖数个探槽研究其近断层水平缩短量的问题,得到结果如下:龙门山中央断裂带映秀镇、擂鼓镇、平通镇探槽近断层水平缩短量分别约为(26±01) m、(26±02) m、(18±01) m;小鱼洞分支断层近断层水平缩短量约为(2±01) m。汶川512地震中央断裂地表破裂近断层较大水平缩短量出现在深溪沟和擂鼓一带,分别约为34 m、32 m;前山断裂地表破裂带近断层水平缩短量最大值出现在白鹿一带,约为25 m,白鹿以北,近断层水平缩短量逐渐减小。中央断裂和前山断裂联合破裂段水平缩短量值之和大于中央断裂带其两侧段落,最大水平缩短量总和可能约为53 m,地表破裂带近断层水平缩短量为整个地壳缩短量的主体部分。

关键词: 汶川Ms 80地震, 近断层, 探槽, 水平缩短量

Abstract:

On May 12, 2008, a great earthquake of Ms 80 occurred in Wenchuan County, Sichuan Province. After this devastating earthquake, many scientists have done detailed field work on the surface rupture zone, especially aiming at the coseismic displacement. However, the nearfault horizontal shortening amount of Wenchuan Ms 80 earthquake, a crucial parameter of coseismic displacement of reverse fault, is relatively less studied. We concluded nearfault horizontal shortening from trenching at some locations along the BeichuanYingxiu Fault and GuanxianJiangyou Fault as: 28 m (Qingping), 32 m (Leigu), 13 m (Pingtong), 25 m (Bailu), 14 m (Jiulong) and 06 m (Hanwang). Based on these studies, we further excavated more trenches along the surface rupture to calculate horizontal shortening. Horizontal shortening from trenches on the BeichuanYingxiu Fault and Xiaoyudong Branch Fault are as: 26±01 m (Yingxiu), 26±02 m (Leigu), 18±01 m (Pingtong), 2±01 m (Xiaoyudong). There are two horizontal shortening peaks in Shenxigou and Leigu along the BeichuanYingxiu Fault, 34 m and 32 m, respectively. Horizontal shortening along the GuanxianJiangyou Fault ranges from 25 m to 06 m, with the highest value toward the southwest. Sums of horizontal shortening on the corupture segment along the GuanxianJiangyou Fault and BeichuanYingxiu Fault are larger than other parts. According to this study, maximum nearfault  horizontal shortening across the surface rupture of the Wenchuan earthquake is about 53 m or slightly larger, which means the shortening near the surface rupture is the main part of the crustal shortening.

Key words: Ms 80 Wenchuan earthquake, nearfault, trench, horizontal shortening amounts

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