【摘要】 苏鲁-大别造山带是中国东部华北、华南地块之间的大地构造交界带。本文分析研究了我国东部的地震活动性,并根据1918~2005年间苏鲁-大别及其周围地区发生的1000余个地震的震源机制解,系统研究了应力场的区域特征以及华北、华南地壳应力场构造分区,探讨了其动力学来源以及构造运动特征。结果表明,中国东部大陆华北、华南地块地壳现代应力场和构造运动可以归结为太平洋板块和菲律宾海板块与欧亚板块之间相对运动,以及大陆板内区域块体之间相互作用的结果。华北地区受到太平洋板块向欧亚板块俯冲挤压的同时,受到从贝加尔湖经过大华北直到琉球海沟的广阔地域里存在着的统一的、方位为170°的引张应力场的控制。华北地区大地震的震源机制解均反映出震源应力场为ENE向挤压应力和NNW向张应力的共同作用。郯庐断裂带等华北地区的北北东走向的断裂带,表现为右旋走滑的现代构造运动特征。来自台湾纵谷的北西西向挤压应力控制了华南块体直至南北地震带南段东部地域的地壳应力场。本文研究结果表明,将中国东部大陆划分成华北、华南两部分的现代地壳应力场分界线,其西部大致与秦岭带相同,然而在大别及其以东地区则逐渐偏离大地构造带,到北纬30°后向东南偏转,在温州附近的北纬27°左右转为向东延伸,最终穿过东海直至琉球海沟。更多还原

【Abstract】 The Sulu-Dabie orogen belt is a tectonic boundary between the North and the South China. In present paper, the regional characteristics of seismic activity, the modern crustal stress field, tectonic motions and its dynamics have been analyzed in East China in detail based on the focal mechanism solutions of more than 1000 middle and great earthquakes occurred during 1918 and 2005. The results suggest that the crustal stress field and tectonic movement in the North China and the South China are attributable to relative motions among the Pacific Ocean, the Philippine Sea and the Eurasian plates, and interactions along blocks of mainland. The North China are controlled by the compressive stress in a NEE direction due to subduction of the Pacific Ocean plate and the identical tensile stress in 170° in a broad region from the Baikal to the Ryukyu trench throughout the North China. The mechanism solutions of large events occurred in the North China showed that they were attributed to the action of the compressive in the NEE direction and the tensile in the NNW direction. The earthquakes occurred along the Tancheng-Lujiang fault and others with the NNE tend towards in the North China were caused by the right strike-slip faults, which also shows the characteristics of tectonic movement here. The compressive force in a NWW direction from the Longitudinal valley in Taiwan controls the crustal stress field in the South China up to the eastern region of southern part of the North-South Seismic Belt (NSB). The results obtained in this study show that there is a boundary of regional crustal stress field between the North China and the South China. This boundary mainly consistent with the Qinling belt in its western part, however, it deviates in and east of the Dabie belt and turns to the south-east at 30°N, passes the Wenzhou area at 27°N, throughout the East Sea of China, finally up to the Ryukyu trench.更多还原