| 2016年M6.2呼图壁地震发震构造及其对天山构造带隆升的启示:来自中近场钻孔应变观测的证据 |
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| 引用本文： | 龚正,李海兵,荆燕,李丽.2016年M6.2呼图壁地震发震构造及其对天山构造带隆升的启示:来自中近场钻孔应变观测的证据[J].地球物理学报,2020,63(4):1386-1402. |
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| 作者姓名： | 龚正 李海兵 荆燕 李丽 |
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| 作者单位： | 1. 中国地震局地球物理研究所, 北京 100081;2. 自然资源部深地动力学重点实验室, 中国地质科学院地质研究所, 北京 100037;3. 中国地震局地壳动力学重点实验室, 中国地震局地壳应力研究所, 北京 100085 |
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| 基金项目： | 国家自然科学基金项目（41702203，41574081）和政府间国际科技创新合作重点专项（2018YFE0100100）联合资助. |
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| 摘 要： | 天山山脉在新生代经历了强烈的构造隆升和地壳缩短作用，其周缘发生的地震活动是了解这一构造模式的窗口.对2016年呼图壁地震的发震构造有两种解读：向南倾斜的低角度逆断层和向北倾斜的高角度逆断层.中近场四台钻孔应变仪记录到了本次地震的同震响应，本文采用均质模型对IGP-CEA和USGS震源机制解进行模拟，结果显示发震断层为向北陡倾的反冲断层，15个原始方位和8个N-S、E-W方位观测值全部与预测值一致.对比天山北缘常见的低角度逆冲断层，反冲断层对构造隆升的贡献更有效，以断层倾角70°和19°计算，二者对隆升和缩短贡献比例分别为2.89：1和1：2.76.这一结果表明天山构造带内部的反冲构造同样具有单独发震的可能性，它们对天山现今的隆升高度同样起着不可忽视的作用.
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| 关 键 词： | 呼图壁地震 构造隆升 钻孔应变仪 同震应变 天山 |
| 收稿时间： | 2019-07-16 |
Seismogenic structure of the 2016 M6.2 Hutubi earthquake and its implication for the uplift process in Tian Shan: Evidence from borehole strainmeters in the near to intermediate field |
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| GONG Zheng,LI HaiBing,JING Yan,LI Li.Seismogenic structure of the 2016 M6.2 Hutubi earthquake and its implication for the uplift process in Tian Shan: Evidence from borehole strainmeters in the near to intermediate field[J].Chinese Journal of Geophysics,2020,63(4):1386-1402. |
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| Authors: | GONG Zheng LI HaiBing JING Yan LI Li |
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| Institution: | 1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China;2. Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;3. Key Laboratory of Crustal Dynamics, China Earthquake Administration, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China |
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| Abstract: | The Tian Shan orogenic belt has experienced intense tectonic uplift and crustal shortening in the Cenozoic due to the Indo-Eurasian collision. Earthquakes happened in the Tian Shan range provide rare opportunities to understand the ongoing tectonic model and the long-term growth of the topography. The 2016 M6.2 Hutubi earthquake is a reverse event happened in the northern Chinese Tian Shan. However, it is controversial whether the seismogenic fault is the low-angle thrust fault that is predominant in this area. Four RZB borehole strainmeters, locating in the near to intermediate field, have recorded the coseismic strain response. Using the elastic model, the theoretic strain of two well-accepted focal mechanisms (the United States Geological Survey and the Institute of Geophysics, China Earthquake Administration) were calculated. Comparisons between the instrument record and the calculated strain show that the seismogenic fault is a high-angle backthrust fault. Fifteen measured offsets at their original azimuths, together with eight offsets in the N-S and E-W direction are consistent with the calculation results when the seismogenic fault is the backthrust fault. The high-angle backthrust fault is more efficient in creating large topographic difference in height than the prevailing low-angle thrust fault. The ratios between the vertical and horizontal displacement are 2.89:1 and 1:2.76 respectively, if the dip angles are 70ånd 19° for the backthrust and thrust faults. It indicates that the backthrust faults in the Tian Shan range are capable of breaking individually, and they have also played a significant role in constructing the modern ultra-high relief in Tian Shan. |
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| Keywords: | Hutubi earthquake Tectonic uplift Borehole strainmeter Co-seismic strain Tian Shan |
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