| 青藏高原东南缘地震活动与地壳运动所反映的块体特征及其动力来源 |
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| 引用本文： | 程佳,徐锡伟,甘卫军,马文涛,陈为涛,张勇.青藏高原东南缘地震活动与地壳运动所反映的块体特征及其动力来源[J].地球物理学报,2012,55(4):1198-1212. |
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| 作者姓名： | 程佳 徐锡伟 甘卫军 马文涛 陈为涛 张勇 |
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| 作者单位： | 1. 中国地震局地质研究所活动构造与火山重点实验室, 北京 100029;
2. 中国地震台网中心, 北京 100045;
3. 中国地震局地质研究所地震动力学国家重点实验室, 北京 100029;
4. 中国地震局, 北京 100036 |
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| 基金项目： | 国家自然科学基金，科技部国际合作计划 |
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| 摘 要： | 通过分析青藏高原东南缘活动断裂带的活动特征和GPS资料显示的现今地壳形变场,辅以历史地震及地表破裂、震源机制解类型等资料,将青藏高原东南缘地区分成了11个次级块体.其中包括了西秦岭次级块体、阿坝次级块体、龙门山次级块体、藏东次级块体、雅江次级块体,香格里拉次级块体、滇中次级块体、保山次级块体、景谷次级块体、勐腊次级块体和西盟次级块体;并利用这些次级块体内的GPS站点速率计算出了这些块体现今运动情况及各块体之间断裂的滑动速率,分析认为各次级块体均受到了一种来自其相邻块体的主要应力作用而发生了旋转,其中保山次级块体、藏东次级块体、雅江次级块体、香格里拉次级块体、滇中次级块体的旋转尤为显著;同样,相邻块体之间的边界断裂带也呈现了相应的挤压或拉张活动特征,而藏东次级块体与雅江次级块体、雅江次级块体与滇中次级块体之间的挤压最为明显.利用上述结果,本文讨论了该地区的现今地壳形变特征,认为刚性块体的挤出作用与重力滑塌作用并存于该区域内,下地壳"管道流"的拖曳作用是该地区刚性块体挤出作用和重力滑塌的主要原因, 另外缅甸板块相对于自身的逆时针旋转作用在其北部引起的拉张作用也是重要因素之一.
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| 关 键 词： | 青藏高原东南缘 GPS 块体模型 历史地震 震源机制 变形机制 |
| 收稿时间： | 2011-05-12 |
Block model and dynamic implication from the earthquake activities and crustal motion in the southeastern margin of Tibetan Plateau |
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| CHENG Jia
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XU Xi-Wei
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GAN Wei Jun
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MA Wen Tao
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CHEN Wei-Tao
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ZHANG Yong.Block model and dynamic implication from the earthquake activities and crustal motion in the southeastern margin of Tibetan Plateau[J].Chinese Journal of Geophysics,2012,55(4):1198-1212. |
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| Authors: | CHENG Jia XU Xi-Wei GAN Wei Jun MA Wen Tao CHEN Wei-Tao ZHANG Yong |
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| Institution: | 1. Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
2. China Earthquake Network Center, Beijing 100045, China;
3. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;
4. China Earthquake Administration, Beijing 100036, China |
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| Abstract: | After analysis of the current crustal deformation field from GPS data,the slip characters of active faults,the surface ruptures of historical earthquakes,and the focal mechanisms of the recent earthquakes,the southeastern margin of the Tibetan plateau was divided into 11 sub-blocks,including the West Qinling sub-block,Aba sub-block,Longmenshan sub-block,Zangdong sub-block,Yajiang sub-block,Shangri La sub-block,Dianzhong sub-block,Baoshan sub-block,Jinggu sub-block,Mengla sub-block and the Ximeng sub-block.The present-day translation and rotation rate of the sub-blocks,also the slip rate of the boundary faults,were calculated using the GPS data.The results show the following characters: Each sub-block has its movement changed after the specific main stress action from the adjacent sub-blocks.Among these sub-blocks,the rotations of the Baoshan sub-block,Zangdong sub-block,Yajiang sub-block,Shangri La sub-block,Dianzhong sub-block,are more obvious than others.Corresponding to the rotations above,the boundary faults among these sub-blocks behave differently.Among these fault activities,the compressions between the Zangdong and Yajiang sub-blocks,as well as between the Yajiang and Dianzhong sub-blocks are obvious.Based on the results above,we discussed the current crustal motion characters of the southeastern margin of the Tibetan plateau.The lateral extrusion of the rigid blocks and gravity collapse of the crust co-exist in the region,which are induced mainly by the "channel flow" of the lower crust,and partly enhanced by the tensile force from the Burma plate due to its counter-clockwise rotation. |
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| Keywords: | Southeastern margin of the Tibetan plateau GPS Block model Historical earthquakes Focal mechanism Deformation mechanism |
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