摘要
渤海是我国东部陆缘海湾地震活动性最高的地区。研究渤海的地震活动特征,对探讨我国沿海地震的成因、沿海现代地质构造活动性质以及海洋石油开发都有一定意义。本文研究了渤海的历史地震资料,除中国大地震目录已发表的地震外,本文新增补了2次6—61/2级地震和3次5级左右地震。讨论了1969年渤海大地震的震源深度,大地震目录给出的深度为35公里(位于地壳以下)。根据其他作者的最新测定的结果和作者等人重新测定的微震震源深度,认为1969年渤海大地震的震源深度为25公里较合适,渤海地震都位于地壳以内。渤海地震活动的时间分布与华北地震区完全一致,渤海地震是华北地震区的一部分。渤海内部的现代构造运动是以水平构造应力场作用下的走滑运动为主要特征。渤海地震活动与北北东向的郯庐断裂的右旋走滑活动以及与其共轭的北西西断裂的左旋走滑活动有关。
Bohai sea is the area of the most intensive seismic activity in the eastern continental margin and bay of the country. It is significant to study on seismicity of Bohai sea not only for probing into seismic genesis and contemporary tectonics of the coast, and also for tapping the oilfield in sea.Historical earthquake data has been studied in this paper. Besides the great earthquakes which have been compiled in the book 'A Catalogue of Great Earthquakes in China', two earthquakes with M = 6-61/2 and three ones with M=5.0 or so are supplemented in this paper. The focal depth of the 1969 Bohai great earthquake, which is given in the catalogue as 35km (below the crust), has been anew determined as 25km according to latest determined results obtained by others and the authors' newly-determined microseimic focal depth. The depth (25km) is more reasonable. Earthquakes occurred in Bohai sea arc all within the crust. Time distribution of seismicity of Bohai sea coincides with that of seimicity of North China. Earthquakes in Bohai sea appear to be a part of seismic area in North China.Contemporary tectonic movement inside Bohai sea is mainly characterized by strike slip motion under horizontal tectonic stress field. Seismicity of Bohai sea is related to the right handed strike slip movement of NNE Tancheng-Luzhou fault and the left-handed strike slip movement of NWW fault which conjugates the Tancheng-Luzhou fault.
出处
《地震研究》
CSCD
北大核心
1989年第1期1-10,共10页
Journal of Seismological Research
关键词
地震活动
活动断裂
构造形变
Seismicity, Focal depth, Active fault, Tectonic stress field, Tectonic deformation, Mechanism of seismic source.
