青海玉树<i>M</i><sub>S</sub>7.1地震发震过程的数值模拟

王连捷; 崔军文; 王薇; 乔子江; 孙东生; 赵卫华

青海玉树M_S7.1地震发震过程的数值模拟

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

基金项目:

国家“973”项目 2008CB425702

国土资源部深部探测技术与试验研究专项 SinoProbe-07

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: 2010-05-25
- 刊出日期: 2010-06-01

NUMERICAL MODELING FOR MECHANISM OF YUSHU M_S7.1 EARTHQUAKE

1.
Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
2.
Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

摘要

摘要: 根据玉树地区的地应力场、速度场和断层展布, 对青海玉树2010年4月14日M_S7.1级地震发震机理进行了数值模拟。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, 当达到断层摩擦破坏强度时, 断层产生应变软化, 断层突然滑动, 能量突然释放, 应力突然下降, 形成地震。模拟结果表明:玉树7.1级地震是在印度板块向北推挤, 青藏高原向东南侧向挤压, 在玉树地区形成主压应力为北东80°方向的水平应力场, 使甘孜-玉树断裂带产生左旋走滑错动形成的。计算结果给出了应力降、能量释放量、断层走滑错动量、地震复发周期、应力积累速度等重要参数, 模拟结果与野外调查资料具有较好的一致性。
- 玉树地震 /
- 地震数值模拟 /
- 应变软化模型 /
- 地震非稳定模型
Abstract: In this paper, strain softening model is used to establish the modeling for Yushu M_S7.1 earthquake. The results shows that Yushu M_S7.1 earthquake occurred as a combination of northward compressing of the Indian Plate and southeastward compressing of the Qinghai-Tibet Plateau. The stress drop, energy release amount, the magnitude of dislocation of fault, and earthquake recurrence intervals are given by the modeling. The modeling results show a good match with the geologic survey in the field.
- Yushu earthquake /
- earthquake modeling: strain-softening model /
- unsteady model of earthquake /

HTML全文

图 1 玉树及周边地区的应力场

Figure 1. Stress field around the Yushu area

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图 2 玉树地震区及周边地区GPS速度场

(据赖锡安等^[19])

Figure 2. Velocity field by GPS around the Yushu area

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图 3 计算模型

a-模型的平面图; b-模型的三维图; D-模型宽度; L-模型长度; H-模型深度; σ_H-最大水平主应力; σ_h-最小水平主应力; v-速度; p-孔隙压力

Figure 3. Model for calculationa

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图 4 模型网格(红线为断层面)

Figure 4. Mesh of model(red is fault plane)

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图 5 地震时断层的突然走向滑动(监测点为图 8 a点)

Figure 5. Sudden sliding of faultwhen the earthquake happened

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图 6 地震时的能量释放

Figure 6. Energy density curvewhen the earthquake happened

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图 7 地震应力降

Figure 7. Stress drop for the earthquake

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图 8 地震引起的沿断层走向的位移/m

(a点为位移监测点)

Figure 8. Fault displacement along strike caused by the earthquake

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图 9 断层两侧位移分布

Figure 9. The displacements on both sides of fault

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表 1 断层和围岩参数

Table 1. Parameters of fault and surroundings

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