| 大凉山次级块体的整体抬升和逆时针转动 |
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| 引用本文： | 姚,琪,宋,金,程,佳,杨,文许,冲,赵,静.大凉山次级块体的整体抬升和逆时针转动[J].地质科学,2017,0(2):328-342. |
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| 作者姓名： | 姚 琪 宋 金 程 佳 杨 文许 冲 赵 静 |
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| 作者单位： | 中国地震台网中心北京 100045；;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 |
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| 摘 要： | 大凉山次级块体现今仍处于强烈隆升状态，周边地震活动频繁，对研究青藏高原东缘晚新生代以来的构造变形和隆升方式具有重要意义。本文基于90 m 分辨率的SRTM 数据，对大凉山次级块体及周边地区的高程进行了200 m 间隔的地形重分类，计算了地形起伏度、坡度及横跨主要断裂的廊带剖面，统计对比了该块体和相邻块体之间的高程-坡度分布。结合地震活动、大地电磁测深剖面、GPS 速度场和地质剖面，发现大凉山次级块的整体高程较高、地形较平坦，向四川盆地阶梯式下降。以安宁河断裂与则木河断裂交汇处为界，块体北部和南部的地形地貌差异较大。北部存在大量挤压抬升，南部挤压分量减少，走滑分量有所增加。在四川盆地和川滇块体的挟持下，大凉山次级块体在南东向运动时，以自身的逆时针旋转变形取代了块体内部的结构破坏和差异隆升，实现北部挤压至南部拉张的构造变形转换和整体抬升。
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| 关 键 词： | 大凉山次级块体 马边—昭通地震带 地形起伏度 整体抬升 鲁甸地震 |
| 收稿时间： | 2015-10-29 |
| 修稿时间： | 2015-10-29; |
Integral uplift and anticlockwise rotation of the Daliangshan sub-block |
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| Yao Qi Song Jin Cheng Jia Yang Wen Xu Chong Zhao Jing.Integral uplift and anticlockwise rotation of the Daliangshan sub-block[J].Chinese Journal of Geology,2017,0(2):328-342. |
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| Authors: | Yao Qi Song Jin Cheng Jia Yang Wen Xu Chong Zhao Jing |
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| Institution: | China Earthquake Networks Center, Beijing 100045；;Institute of Geology, China Earthquake Administration,Beijing 100029 |
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| Abstract: | Daliangshan sub-block is still uplifting nowadays and moderate-strong earthquakes occurred around, such as the 2014 Ludian MS 6.5 earthquake and 2014 Kangding MS 6.3 earthquake. We resort the elevation with 200 m interval, and illustrate the local relief, the slop, transverse swath profiles, and the mean slop as a function of evolution of the Daliangshan sub-block and its neighborhood using SRTM data. In the north, the high elevation of 3 000～4 500 m maintains in E-W 70～115 km wide and the elevation step down from the Ebian-Jinyang fault to the Mabian fault. Inside the Daliangshan block, narrow N-S thrusts with high elevation separated by parallel valley indicate the compression and whole-slab uplift of the block. All regions with high local relief and high slop lay on the hanging wall. In the south, there is still high elevation of 3 000 m in wide range, however, the elevation slowly down to the Sichuan Basin. The regions of high local relief and high slop lay not only around the faults but also around the river. Based on seismicity, magnetotelluric sounding data, GPS velocity field and geological sections, the topographic relief of the Daliangshan sub-block is mainly controlled by whole-slab uplift in the north, and then gradually controlled by strike-slip displacement in the south. The Ebian-Jinyang fault is the actually boundary of the block and the Mabian fault is piedmont thrust belt, such as the central faults and piedmont faults in Longmenshan. |
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| Keywords: | Daliangshan sub-block Mabian-Zhaotong seismic belt Local relief Integral uplift Ludian earthquake |
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