Active tectonics and intracontinental earthquakes in China: The kinematics and geodynamics
Active tectonics and intracontinental earthquakes in China: The kinematics and geodynamics
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DOI：
10.1130/2007.2425(19
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Mian Liu;Youqing Yang;Zheng‐Kang Shen;Shimin Wang;Min Wang;Y. Wan
中科院分区：
文献类型：
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作者：
Mian Liu;Youqing Yang;Zheng‐Kang Shen;Shimin Wang;Min Wang;Y. Wan
我国是一个陆内地震强烈的国家。中国西部的大多数地震发生在印度-欧亚板块边界扩散带内，该边界带向亚洲延伸数千公里。中国东部的地震主要发生在华北地块内，华北地块是太古代中朝克拉通的一部分，自中生代晚期以来经历了热再生。在这里，我们总结了地壳运动学的新构造和大地测量结果，并利用数值模型探讨了它们对地球动力学和地震活动的影响。第四纪断层运动和全球定位系统（GPS）测量表明印度-亚洲碰撞对中国大陆地壳运动产生了强烈影响。使用球形三维（3-D）有限元模型，我们表明碰撞板块边界力的影响很大程度上局限于中国西部，而青藏高原的重力扩散对亚洲大部分地区的地壳变形有着广泛的影响。华北地块的强烈地震活动和华南地块缺乏地震活动的主要原因可能是由于构造边界条件在华北地块内产生高偏应力，但允许华南地块作为刚性块体进行连贯运动。华北地块内，地震活动集中于环鄂尔多斯裂谷，反映了岩石圈非均质性的控制。最后，我们计算了1303年以来华北地块49次大地震（M≥6.5）的库仑应力变化。结果表明，约80%的事件发生在由先前事件引起的库仑应力增加的区域。
China is a country of intense intracontinental seismicity. Most earthquakes in western China occur within the diffuse Indo-Eurasian plate-boundary zone, which extends thousands of kilometers into Asia. Earthquakes in eastern China mainly occur within the North China block, which is part of the Archean Sino-Korean craton that has been thermally rejuvenated since late Mesozoic. Here, we summarize neotectonic and geodetic results of crustal kinematics and explore their implications for geodynamics and seismicity using numerical modeling. Quaternary fault movements and global positioning system (GPS) measurements indicate a strong infl uence of the Indo-Asian collision on crustal motion in continental China. Using a spherical three-dimensional (3-D) fi nite-element model, we show that the effects of the collisional plate-boundary force are largely limited to western China, whereas gravitational spreading of the Tibetan Plateau has a broad impact on crustal deformation in much of Asia. The intense seismicity in the North China block, and the lack of seismicity in the South China block, may be explained primarily by the tectonic boundary conditions that produce high deviatoric stresses within the North China block but allow the South China block to move coherently as a rigid block. Within the North China block, seismicity is concentrated in the circum-Ordos rifts, refl ecting the control of lithospheric heterogeneity. Finally, we calculated the change of Coulomb stresses associated with 49 major (M ≥ 6.5) earthquakes in the North China block since 1303. The results show that ~80% of these events occurred in regions of increasing Coulomb stresses caused by previous events.