汶川5.12地震发震机理的数值模拟

王连捷; 崔军文; 周春景; 孙东生; 王薇; 唐哲民; 钱华山

汶川5.12地震发震机理的数值模拟

1.
中国地质科学院地质力学研究所, 北京 100081
2.
中国地质科学院地质研究所, 北京 100037
3.
北京超算科技有限公司, 北京 100085

基金项目: 国家科技支撑—汶川地震断裂带科学钻探井中探测项目资助

详细信息

作者简介:
王连捷(1933-), 男, 研究员, 从事地质灾害、地应力测量、应力场数值分析及应用研究。E-mail:wanglj01@sina.com

中图分类号: P315.01
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- 被引次数: 0
出版历程
- 收稿日期: 2009-05-10
- 刊出日期: 2009-06-01

NUMERICAL MODELING FOR WENCHUAN EARTHQUAKE MECHANISM

1.
Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
2.
Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
3.
Beijing Supcompute Technology Co., Ltd., Beijing 100085, China

摘要

摘要: 将围岩看成弹性体, 断层看成具有应变软化的弹塑性体, 断层和围岩组成统一的地质介质系统。在给定的地应力、孔隙压力及边界位移的作用下, 应力逐渐积累, 当达到断层强度时, 断层进入塑性状态, 应变随之软化, 应力突然下降, 能量突然释放, 形成地震。根据这个原理, 利用有限差分FLAC软件, 对汶川5.12地震的机理进行了模拟。模拟结果证实：汶川5.12地震是在青藏高原侧向挤压, 四川盆地阻挡, 使龙门山断裂带受到缓慢增加的挤压应力场作用下形成的。计算结果给出了应力降、能量释放量、断层错动量、地震同震位移、震前位移、地震复发周期等重要参数, 结果与野外调查及其它资料给出的数据具有较好的一致性。
- 汶川地震 /
- 龙门山断裂带 /
- 应变软化模型 /
- 地震非稳定模型
Abstract: In this paper, strain softening model is used for modeling the Wenchuan earthquake.Results shows that this earthquake was caused by compressing of Qinghai-Tibet Plateau and block of Sichuan Basin.The stress drop, energy release amount, the magnitude of dislocation of fault, coseismic displacement, displacement before earthquake and earthquake recurrence intervals are given by the modeling.The modeling results are in good agreement with geologic and geomorphologic survey and others data.
- Wenchuan earthquake /
- Longmenshan fault /
- strain-softening model /
- unsteady model of earthquake
注释:
编者按:
在汶川地震一周年之际, 本刊发表一组有关汶川地震的论文, 谨此纪念。这是我所广大科研人员怀着对祖国、对人民的无限深情, 一年来辛勤耕耘取得的部分科研成果。汶川强震给我国人民带来深重灾难的同时, 也给我们提出了不少新的研究课题。由于每个强震都有其自身独有的特点, 只有不断深入地研究诸多强震的特点, 才能深入理解强震发生机理及演化规律。就汶川地震而言, 还有不少问题有待深入研究。做为大型综合性地学刊物, 本刊欢迎各界提供这方面的稿件。

HTML全文

图 1 地震模拟剖面位置^[3] (A-B为地震模拟剖面)

Figure 1. Location of the simulated earthquake profile

下载: 全尺寸图片幻灯片

图 2 地震模拟剖面的边界应力、位移速度和约束条件

(模型中考虑铅直应力、孔隙压力、水平地应力和位移速度)σ_H.水平应力; σ_v.铅直应力; P.孔隙压力; V.位移速度

Figure 2. Boundary condition of the simulated earthquake

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图 3 应力降

Figure 3. Diagram of stress drop

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图 4 系统总能量曲线

Figure 4. Diagram of total energy

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图 5 沿断层面位错分布(彩色条带为断层面)等值线单位/m

Figure 5. Distribution of displacement along fault

下载: 全尺寸图片幻灯片

图 6 断层附近同震位移(铅直)分布等值线单位/m

Figure 6. Distribution of coseismic displacement near fault (vertical)

下载: 全尺寸图片幻灯片

图 7 地表位移曲线(垂直)

1.同震位移; 2.临震前; 3.震前500年; 4.震前1000年

Figure 7. Curves of the earth surface displancement (vertical)

下载: 全尺寸图片幻灯片

图 8 应力的积累与地震复发周期

Figure 8. Earthquake recurrence intervals

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表 1 断层和围岩参数

Table 1. Parameters of faults and surrounding rocks

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