| 青藏高原东南缘地幔对流与发震层应力场耦合关系分析 |
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| 引用本文： | 侯强,姚亚峰,丁小军,欧明霖,张博康.青藏高原东南缘地幔对流与发震层应力场耦合关系分析[J].大地测量与地球动力学,2019,39(9):890-895. |
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| 作者姓名： | 侯强 姚亚峰 丁小军 欧明霖 张博康 |
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| 作者单位： | 中国地质大学(武汉)机械与电子信息学院,武汉市鲁磨路388号,430074;中国地质大学(武汉)机械与电子信息学院,武汉市鲁磨路388号,430074;中国地质大学(武汉)机械与电子信息学院,武汉市鲁磨路388号,430074;中国地质大学(武汉)机械与电子信息学院,武汉市鲁磨路388号,430074;中国地质大学(武汉)机械与电子信息学院,武汉市鲁磨路388号,430074 |
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| 基金项目： | 中央高校基本科研业务费专项资金 |
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| 摘 要： | 利用EGM2008重力模型的11~36阶球谐系数计算青藏高原东南缘岩石圈底面地幔对流应力场，收集整理青藏高原东南缘2000年至今的1 131个震源机制解数据，采用区域应力张量阻尼反演法得到该区芦山地震前和现今的发震层应力场，进一步分析2种应力场的相关性，探讨不同区域的力学耦合情况与强震发生的关系。结果表明：1)青藏高原东南缘大部分位于耦合与解耦的中间地带，耦合区域基本按块体分布，东侧华南块体强耦合，西北部藏北块体、巴颜喀拉块体和西南部滇西南块体部分耦合，解耦主要发生在松潘-甘孜块体附近，以龙门山断裂带连接强耦合的华南块体；2)分析孕震原因，提出青藏高原东南缘地幔对流应力场与发震层应力场耦合程度强弱交界处为地震危险性较高的区域，从现今耦合关系来看，龙门山断裂带仍处于耦合强度变化梯度非常大的区域，具备孕震储能条件，地震危险性较高。其他危险区域大致有：岷江断裂带附近、鲜水河-安宁河-则木河断裂带附近、红河断裂带及南汀河断裂带附近。
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| 关 键 词： | 青藏高原东南缘 发震层应力场 地幔对流 耦合关系 壳内软弱带 |
Coupling Relationship between Mantle Convection and Seismic Stress Field in Southeastern Tibetan Plateau |
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| HOU Qiang,YAO Yafeng,DING Xiaojun,OU Minglin,ZHANG Bokang.Coupling Relationship between Mantle Convection and Seismic Stress Field in Southeastern Tibetan Plateau[J].Journal of Geodesy and Geodynamics,2019,39(9):890-895. |
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| Authors: | HOU Qiang YAO Yafeng DING Xiaojun OU Minglin ZHANG Bokang |
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| Abstract: | We calculate the lithospheric bottom mantle convection stress field of southeastern Tibetan plateau using 11~36 spherical harmonic coefficients of gravity model EGM2008. Meanwhile we collect and organize the focal mechanism of 1 131 earthquakes that occurred from 2000 to the present in southeastern Tibetan plateau. The current seismogenic layer stress and stress field before Lushan earthquake are calculated by the damping regional stress tensor inversion. We further analyze the correlation between the two kinds of stress fields, then discuss the relation between mechanics coupling situation and strong earthquakes in different regions. The results show that: (1) Most of southeastern Tibetan plateau is located in the coupling and decoupling intermediate zone. Coupling zones distribute on the basis of block; the eastern south China block has strong coupling, and the coupling phenomenon also exists in parts of the northern Tibet block, Bayan Har block in the northwest, and southwest Yunnan block. The decoupling mainly occurs in Songpan-Ganzi block, connecting with the strong coupling south China block and Longmenshan fault zone, which is their boundary. (2) We analyze the seismogenic mechanism, then propose that the border zone, of strong and weak coupling relation between mantle convection stress and seismogenic layer stress, presents a high seismic risk. The current coupling situation shows that Longmenshan fault zone is still in the large varying gradient area of coupling intensity level, and has conditions to accumulate energy and develop earthquakes. Other dangerous areas are: Mingjiang fault zone, Xianshuihe-Anninghe-Zemuhe fault zone, the Red river fault zone, Nantinghe fault zone and their neighboring areas. |
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| Keywords: | southeastern Tibetan plateau seismogenic layer stress field mantle convection coupling relation intracrustal weak zone |
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