| 甘东南及邻区7级以上强震数值模拟 |
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| 引用本文： | 杨兴悦,曾文浩,王燕,李少华,孙召华.甘东南及邻区7级以上强震数值模拟[J].地球科学,2016,41(7):1238-1248. |
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| 作者姓名： | 杨兴悦 曾文浩 王燕 李少华 孙召华 |
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| 作者单位： | 1.甘肃省地震局，甘肃兰州 730000 |
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| 基金项目： | 甘肃省地震局地震科技发展基金项目面上基金2013M03 |
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| 摘 要： | 对强震发生后周围断层及未来强震形势的影响研究具有非常重要的意义.青藏高原东北缘强震频发，对该区的历史强震进行研究很有必要.以青藏高原东北缘及邻区为目标建立3D黏弹性有限元模型，依据中国大陆Ⅰ级块体和青藏高原Ⅱ级块体划分及活动断裂分布确定模型块体边界及断裂位置，使用GPS观测资料作为模型边界条件，数值模拟1900年以来7级以上强震发生的动力学过程.计算结果表明:① 青藏高原东北缘及邻区区域水平构造应力场特征大致呈从西向东，从南向北减小分布.② 模拟结果说明强震主要发生在背景场应力和强震引起的等效应力加载的断层上.③ 历史强震序列对1970年以来地震的影响:康定地震加速触发了炉霍地震的发生；康定、炉霍地震对松潘地震无加速触发作用；康定、炉霍、松潘地震对共和地震无加速触发作用；炉霍、松潘、共和地震对汶川地震的影响较小；汶川地震延缓了芦山地震的发生.
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| 关 键 词： | 青藏高原东北缘 黏弹性 有限元 强震 数值模拟 地震 |
| 收稿时间： | 2015-12-18 |
Numerical Simulation on Magnitude 7 or over Earthquakes in Southeast Gansu Province and Its Neighboring Areas |
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| Abstract: | It is very important to study the influence of the strong earthquake on the surrounding fault and its development trend in future. Strong earthquakes occurred frequently in the northeastern margin of the Qinghai-Tibet Plateau, thus it is necessary to study the history of strong earthquakes in this region. We construct the 3D viscoelastic finite element model of the northwest margin and its surroundings of Qinghai-Tibet Plateau, on the basis of level Ⅰblocks in China continent and level Ⅱ blocks in Qinghai-Tibetan Plateau and distribution of active faults to determine the model block boundary and fault location in this paper. In addition, the dynamic process of strong earthquakes (Ms≥7.0) since 1900 is simulated using GPS observation data as boundary conditions, The calculation results are as follows. (1) The regional horizontal tectonic stress field in northeastern margin of Tibetan Plateau is characterized by gradual decrease from west to east and decrease from south to north as well. (2) The simulation results show that the strong earthquakes are mainly caused by the equivalent stress loaded on the background field and the strong earthquakes. (3) The effects of historical earthquake sequence to the earthquakes since 1970 are also discussed. It is concluded that the Kangding earthquake triggered the occurrence of Luhuo earthquake acceleratedly, while the effect of Kangding earthquake, Luhuo earthquake and Songpan earthquake on Gonghe earthquake is not obvious, meanwhile, the influence of Luhuo earthquake, Songpan earthquake and Gonghe earthquake on the Wenchuan earthquake is little; and the Wenchuan earthquake delayed the occurrence of Lushan earthquake. |
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