长江经济带地区活动构造与区域地壳稳定性基本特征

基于长江经济带地区活动断裂资料的收集整理和总结，结合新的遥感解译与地表调查结果，初步归纳了该区的活动构造基本特征，梳理出直接或间接威胁重要城市群、国家级新区和区域重要交通过江通道地壳稳定性的主要活动断裂及应对建议或对策，并进一步重点指出长江中下游成都-上海沿江地区的32条重要活动断裂带及其穿越或影响到的主要城市群和重大工程。在活动断裂梳理结果基础上，总结提出长江经济带西部的强烈地壳变形与地震活动主要由印度板块与欧亚板块碰撞作用下在青藏高原东南缘地区形成的“川滇弧形旋扭活动构造体系”所控制，而中-东部地区属于印度板块与西太平洋板块共同作用下区域性挤压-剪切变形导致的具有共轭走滑断裂系统特征的“棋盘格子式”活动构造体系格局，其中需要特别关注7条典型活动断裂带的活动性及其对城市群地壳稳定性的影响。根据区域的活动构造体系、活动断裂与历史地震活动性等特点，初步归纳了该区的未来地震危险性问题及应重点关注的潜在强震危险区段，指出了典型的区域古地震地质遗迹特征及开展古地震调查研究的重要性。同时，依据长江经济带地区初步的区域地壳稳定性评价结果，认为次不稳定区和不稳定区主要集中在西部地区，而中-东部地区以次稳定区与相对稳定区为主，仅郯庐断裂带及其周边存在较明显的次不稳定区。最后，指出了长江经济带活动构造与区域地壳稳定性调查评价工作在活动断裂地质调查研究和城市活断层鉴别与地震危险性评价中面临的主要问题与挑战。 

THE ACTIVE TECTONICS AND REGIONAL CRUSTAL STABILITY FEATURES IN THE AREA OF YANGTZE RIVER ECONOMIC BELT

Combining the new Remote sensing interpretation and the result of surface survey with the active faults data on the Yangtze River Economic Belt, we preliminarily summarized the active tectonic features in this area, and teased out the main active faults that directly and indirectly threating to crustal stability of important urban agglomerations, state-level new district and river-crossing channels at the Yangtze River Economic Belt region, then pointed out 32 important active faults along Chengdu-Shanghai region that belongings to the middle and lower reaches of Yangtze River Economic Belt, and the influenced major urban agglomerations and major projects. After teasing out the active faults, we put forward that the strong crustal deformation and seismicity of western Yangtze River Economic Belt are mainly controlled by "the Sichuan-Yunnan arc rotational-shear active tectonic system" at southeastern margin of Qinghai-Tibetan Plateau that formed under the action of the collision between Indian Plate and Eurasian Plate. But the middle-eastern area of Yangtze River Economic Belt is a "check board" active tectonic system that has the characteristics of conjugate strike slip fault which caused by the regional extrusion shearing deformation under the action of Indian Plate and Western Pacific Plate, 7 typical active faults'' activity and their influences to the crustal stability of urban agglomeration required especially attentive. According to the features of regional active tectonic system, active faults and historic seismic activities, we preliminarily summarized the problems of future seismic hazard in this area, and the potential strong earthquake risk segment that needs to be focused on, then identified the importance of surveying the characteristics of geological relics of typical regional paleoearthquakes and paleoearthquake study. Further, the preliminary evaluation of regional crustal stability in the Yangtze River Economic Belt region showed that the unstable and sub-unstable regions are mainly concentrated in the western region, and the most of central-eastern regions are belong to the sub-stable and stable regions, but there are a few obvious sub-unstable regions along the Tanlu fault zone. Finally, we pointed out the main problems and challenges on the field surveying and evaluation of active tectonics and regional crustal stability, and the active fault identification and seismic risk evaluation of major city area in the Yangtze River Economic Belt.