【摘要】 台湾海峡两岸存在一系列断续分布、横贯台湾海峡的NW向断裂,研究表明为一系列具有走滑运动的横向构造,根据地壳运动、区域变形和断裂特征分为巴士断裂带、台中-晋江断裂带和宁德-三貂角断裂带。中部的台中-晋江断裂带是一条控制地壳运动南北差异的重要分界断裂,断裂带以北的东南沿海北部和台湾北部地壳整体向东运动,与琉球俯冲带右行走滑运动方向基本相同,形成一致的变形取向;断裂带以南处于华南地块与菲律宾海板块相向运动挤压变形环境,地壳变形比北部强烈。东南沿海地震强度增强趋势、地震南强北弱与该应变场和横向走滑有关:(1)由于该断裂以南比以北地区应力应变场变化大,多场耦合复杂,耦合程度降低,造成蠕动变形不均产生应力闭锁,孕育地震发生。(2)福建东部比台湾海峡地壳均一性差、地球物理场变化明显,组成更为复杂的多元、多场耦合,耦合场稳定性差,容易受横向构造活动干扰,产生弹性变形而孕育地震强度增强。更多还原

【Abstract】 There are a series of NW-trending faults along the Taiwan Strait. Studies show that a series of transverse structures with strike-slip movements could be divided into three types according to the crustal movement,region deformation and fracture characteristic. The three types are the Bashi,Taizhong-Jingjiang and Ningde-Sandiaojiao fault zones respectively. The middle Taizhong-Jingjiang faulted zone is an important boundary which controls the different crustal movements between the north and the south. The whole crusts in the north(northern coastal Southeast China and northern Taiwan) move eastward,which is the same direction as the strike-slip movement of the Ryukyu subduction zone,and forms the same deformation direction. The south of the fault zone is under the compressive deformation environment between the South China Plate and Philippine Sea Plate,whose deformation is more intense than that of the north. The strengthening trend of seismicity in coastal Southeast China and the situation of stronger seismicity in the south than in the north are related to the stress field and strike-slip: (1) The stress field changes greater in the south fracture than in the north fracture,multi-fields couple complicatedly and the coupled degree decreases,leading to the asymmetric distribution of creep deformation and stresses locking,therefore,these contribute to the occurrence of earthquakes. (2) Crust uniformity in the east of Fujian is worse than the Taiwan Strait,geophysical field changes obviously,and the components of multi-fields coupling and multi-factors coupling fields are more complicated. Thus,the stability of coupling fields is not high,and it is easily disturbed by the transverse structural strike-slip to produce elastic deformations which contribute to the increase of seismicity.更多还原