【摘要】 湘东地区(湖南省东部地区)地处华南褶皱系内,经历了多次构造运动,地层普遍褶皱,并伴有一系列NNE—NE向断裂,沿这些断裂形成一些断陷盆地;新构造运动期间,地壳运动以大面积整体性缓慢抬升为主要形式,差异性构造活动较弱,但该区发生了多次中强地震,断裂在第四纪早、中期有活动可能与中强地震的发生有关。文中在收集、分析研究区及附近地区前人工作成果的基础上,对常德-益阳-长沙断裂东南段、湘潭-邵东断裂东北段和永州-衡阳断裂开展了地质学、地貌学的野外考察,综合分析了这些断裂第四纪早、中更新世以来的活动性。采用"地震重复"和"构造类比"2条基本原则,依据特定地段的地质、地震和地球物理场等资料,认为这些断裂带不但具有中更新世活动形迹,而且沿带存在中强地震的潜在危险。综合社会和经济发展的需求等因素,将湘潭—湘乡、邵东、衡山—衡阳、永州等地带划分为新的潜在震源区。更多还原

【Abstract】 Located in the south China fold system,the eastern Hunan area has experienced several tectonic movements,which resulted in wide-spread distribution of folds accompanied by a series of NNE-NE trending faults,and some rift basins were developed along these faults. During the neotectonic movement,the crustal movement was dominated by large-scale and overall slow uplift with weak differential tectonic movement. However,this area has experienced a number of strong earthquakes,which are supposed to be related to the fault activities in the mid-Quaternary. Based on the collection and analyses of previous results of research in this area and its neighborhood,in this study,we carried out field geological and geomorphologic investigation to the southeastern segment of Changde-Yiyang-Changsha Fault,the northeastern segment of the Xiangtan-Shaodong Fault,and the Yongzhou-Hengyang Fault. Comprehensive analysis was made on the activity of these faults during the early Pleistocene epoch based on the two basic principles of "earthquake recurrence" and "structural analogy". Based on the geological,seismic and geophysical data of specific sites,it is concluded that these fault zones not only put up the evidence of mid Pleistocene activities,but have potential risk of moderate earthquakes in the areas around the fault zones. Considering the needs for social and economic development and other factors,the Xiangtan-Xiangxiang,Shaodong,Hengshan-Hengyang,and Yongzhou areas are regarded as new potential source regions.更多还原