| 2013年7月22日甘肃岷县-漳县M_S6.6地震震源破裂过程 |
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| 引用本文： | 孙蒙,王卫民,王洵,何建坤.2013年7月22日甘肃岷县-漳县M_S6.6地震震源破裂过程[J].地球物理学报,2015,58(6):1909-1918. |
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| 作者姓名： | 孙蒙 王卫民 王洵 何建坤 |
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| 作者单位： | 大陆碰撞与高原隆升重点实验室, 中国科学院青藏高原研究所, 北京 100101 |
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| 基金项目： | 国家自然科学基金项目 (41174037)资助. |
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| 摘 要： | 2013年7月22日,在甘肃岷县漳县交界处发生MS6.6地震,地震震中位置靠近临潭—宕昌断裂.本文通过构建有限断层模型,利用国家强震动台网中心提供的12条强地面运动三分量资料,通过波形反演方法来研究这次地震的震源破裂过程.结果显示这次地震是发生在甘东南地区岷县—宕昌断裂带东段附近的一次MW6.1级逆冲兼具左旋走滑破裂事件,最大滑动量约为80cm.发震断层走向及滑动性质与岷县—宕昌断裂吻合,推断本次地震与东昆仑断裂向北的扩展和推挤密切相关,是岷县—宕昌断裂进一步活动的结果.
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| 关 键 词： | 岷县-漳县地震 强地面运动 模拟退火方法 震源破裂过程 |
| 收稿时间： | 2014-10-30 |
Rupture process of the Minxian-Zhangxian,Gansu, China MS6.6 earthquake on 22 July 2013 |
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| SUN Meng,WANG Wei-Min,WANG Xun,HE Jian-Kun.Rupture process of the Minxian-Zhangxian,Gansu, China MS6.6 earthquake on 22 July 2013[J].Chinese Journal of Geophysics,2015,58(6):1909-1918. |
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| Authors: | SUN Meng WANG Wei-Min WANG Xun HE Jian-Kun |
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| Institution: | Key Laboratory of Continental Collision and Plateau Uplift (LCPU), Institute of Tibetan Research, Chinese Academy of Sciences, Beijing 100101, China |
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| Abstract: | On July 22, 2013, a major earthquake (MS6.6) occurred on the boundary of Minxian and Zhangxian in Gansu province, with its epicenter near the Lintan-Dangchang fault. Based on the finite fault model constructed, the rupturing process of this earthquake was determined by the waveform method using 12 near source strong motion three-component records provided by China Earthquake Data Center.Strike, dip angle, and rake angle of seismogenic fault as well as focal depth are supposed to be known before the waveform inversion based on a finite fault model. The focal mechanism of the earthquake is obtained by a dislocation source model utilizing 30 far-field P vertical waveform records with uniform azimuth coverage and 12 near-field P-wave initial motions. Geometric parameters of the seismogenic fault plane and focal depth adopted in the inversion were determined by considering information such as results of different institutions and scholars, waveform fitting obtained by treating two nodal planes as fault planes, and strike of existing faults in this area. The strike is 300.2°, dip angle is 66°, slip angle is 47.7°, focal depth is 7 km. In the process of inverting rupture process of this earthquake using strong motion records, Green's function was calculated by f-k integration and source parameters over the fault,including slip amount, slip rake, rise time and rupture velocity,which were inverted by simulated annealing method. In order to check the accuracy of source parameters deduced by strong motion records, we use the deduced source parameters to calculate the far-field synthetic waveforms and then compare them with observed ones.Results show that slip over the seismogenic fault is centralized nearby the focal source, maximum slip is around 80 cm, and no slip on the surface of ground. This earthquake is dominated by over-thrust with sinistral strike-slip component, consistent with other faults in this area. The rupturing ended at 8 s. Seismic moment M0 is 1.60×1025dyn·cm, moment magnitude MW is 6.1.Considering the strike of the seismogenic fault and aftershocks' distribution matches with Lintan-Dangchang fault, rake and dip of seismogenic fault are also similar to those of eastern part of Lintan-Dangchang fault, we deduce this earthquake was related with the north forward extrusion of the east Kunlun fault and resulted from the further activity of the Minxian-Dangchang fault. |
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| Keywords: | Minxian-Zhangxian earthquake Strong ground motion Simulated annealing method Rupture process |
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