长江中游湖南、湖北地区主要活动断裂及地震地质特征

GEOLOGICAL CHARACTERISTICS OF THE MAIN ACTIVE FAULTS AND EARTHQUAKES IN HUNAN AND HUBEI AREAS,THE MIDDLE REACHES OF THE YANGTZE RIVER

通过收集整理前人成果资料,结合湖南、湖北地区地震地质特征、历史近代地震数据等,全面梳理分析该区主要活动断裂及历史地震,总结该区主要活动断裂系(带)及控震特征、地震活动性及时空分布特征。研究结果表明,该区主要活动断裂以北东、北北东、北西向为主,主要活动断裂系有6个,自北向南分别为秦昆北西向断裂系、鄂东北东向断裂系、江汉—洞庭盆地断裂系、鄂西—湘西北东向断裂系、湘中南北东向断裂系、湘东北东向断裂系,其中第四纪活动较为显著且影响程度大的是江汉—洞庭盆地断裂系及秦昆北西向断裂系西段。"两湖"地区地震活动水平相对较低,正处于第三活动期的相对平静期。结合近代中强震资料及中国地震烈度区划特征分析认为,江汉—洞庭盆地南部的东、西边界、鄂州—黄冈—武汉一带以及鄂西北断块隆起区地壳较不稳定,具有发震潜力,应在城市群规划建设、护江大堤设防和重大工程建设中予以特别关注。

In this paper,the predecessors ＇achievements were collected and combined with the historical and modern seismic data in Hunan and Hubei areas. The major active faults and historical earthquakes in the areas, characteristics of the main active earthquake-controlled fault system（ belt）,seismic activity and spatial and temporal distribution were summarized. Research results indicate that the trends of major active faults in this region are mainly of NE,NNE and NW. There are 6 main active fault systems from north to south,including NW trending Qinkun fault system,NE trending fault system in the east of Hubei,Jianghan-Dongting basin fault system,NE trending fault system from west Hubei to west Hunan,NE trending fault system in central and south Hunan,and NEE trending fault system in east of Hunan. Quaternary activities of Jianghan-Dongting basin fault system and NW trending Qinkun fault system are more significant. Seismic activity level in the ＂Two Lakes＂area is relatively low,being in the relatively calm period of the third activity period.Combining modern medium-strong earthquakes data with characteristics of China＇s seismic intensity zoning,we believed that crust is unstable in the east and west boundaries of the south of JianghanDongting basin,the Ezhou-Huanggang-Wuhan area and fault block uplift area in northwestern Hubei,with higher potential earthquake risk,which should be paid more attentions in the planning and construction of the urban agglomeration,protecting river embankment design and construction of major projects.