| 青藏高原巴颜喀拉地块构造形变特征的数值模拟 |
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| 引用本文： | 孙玉军,范桃园,周春景,吴中海.青藏高原巴颜喀拉地块构造形变特征的数值模拟[J].地质通报,2015,34(1):71-82. |
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| 作者姓名： | 孙玉军 范桃园 周春景 吴中海 |
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| 作者单位： | 中国地质科学院地质力学研究所,北京,100081 |
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| 基金项目： | 中国地质调查局项目，国家自然科学基金项目，中央级公益性科研院所基本科研业务费项目 |
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| 摘 要： | 1997年以来发生在青藏高原主体的一系列强震均围绕巴颜喀拉地块周缘断裂带分布。在现今GPS观测的约束下,利用弹塑性平面应力有限元模型,模拟分析了巴颜喀拉地块在周缘断裂带控制下的构造形变特征。结果表明,弹性模型不能解释现今利用GPS观测到的巴颜喀拉地块的构造形变特征,当昆仑山断裂带中段和玉树—鲜水河断裂带处于塑性屈服状态(有较大相对滑动)时,计算得到的速度场与GPS的观测值吻合较好,表明该区现今的地壳运动主要被这2条断裂的变形所吸收。进一步的模拟分析发现,如果依据断裂带上强震的复发周期给定各个断裂带的相对塑性屈服强度,则在玉树—鲜水河断裂带和东昆仑断裂带中段进入塑性屈服之后,玛尔盖茶卡—若拉岗日断裂带玛尼段和黑石北湖断裂带会先后进入破裂滑动状态,东昆仑断裂带东段和龙门山断裂带南段最后进入屈服状态,指示巴颜喀拉地块的整体运动在周缘断裂带控制下具有分段性和分期性。
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| 关 键 词： | 巴颜喀拉地块 数值模拟 弹塑性 构造形变 |
Numerical modeling analysis of the tectonic deformation of Bayan Har block in the Tibetan Plateau |
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| SUN Yujun,FAN Taoyuan,ZHOU Chunjing,WU Zhonghai.Numerical modeling analysis of the tectonic deformation of Bayan Har block in the Tibetan Plateau[J].Geologcal Bulletin OF China,2015,34(1):71-82. |
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| Authors: | SUN Yujun FAN Taoyuan ZHOU Chunjing WU Zhonghai |
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| Institution: | Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China |
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| Abstract: | A series of strong earthquakes have occurred in the Tibetan Plateau since 1997, distributed along the peripheral faults of Bayan Har block. It is necessary to study the overall tectonic deformation of Bayan Har block. With the constraints from GPS observation, the tectonic deformation of the Bayan Har block and its periphery faults was investigated based on an elasto-plastic plane stress finite element model. The results show that the elastic model could not explain the current GPS observation in the Bayan Har block. When East Kunlun fault and Yushu-Xianshuihe fault were in the plastic yield state (with relative large sliding), the calculated velocity field is consistent well with the observation values, suggesting that most of the current shear deformations (strain localizations) were absorbed by these two faults. In addition, if the recurrence intervals of large earthquakes are used to limit the relative yield strength of major faults, the major faults around Bayan Har block entered the plastic yield state in the following order: The Yushu-Xianshuihe faults and the middle segment of East Kunlun faults first entered the yield state in succession. Then, the Margaichaka-RolaKangri faults (Mani segment) and Heishibeihu faults would enter the yield state, and the eastern segment of East Kunlun faults and Longmenshan faults entered the yield state at last. This indicates that the overall movement of Bayan Har block shows sectional and periodical characteristics. |
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| Keywords: | Bayan Har block numerical simulation elasto-plastic model tectonic deformation |
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