【摘要】 讨论了全球39个俯冲带内的双地震带层间距、应力类型与俯冲参数的相互关系,这些俯冲参数包括动力学参数(板块年龄、热参数、板片拉力)、运动学参数(俯冲板块速度、上覆板块运动速度、海沟迁移速度、弧后形变特征)、几何形态参数(浅俯冲角、深俯冲角、俯冲深度、长度)及上覆板块性质等.结果表明:(1)Ⅰ型双地震带易形成于年龄较古老(>60 Ma)的俯冲板块,其层间距主要与动力学参数有关;(2)Ⅱ型双地震带出现在较年轻(<60 Ma)的板块,其层间距及应力状态更容易受局部应力场的影响;(3)当热参数大于5000 km时仪能形成Ⅰ型双地震带,而当热参数小于5000 km时,两类双地震带都能形成;(4)上覆板块的性质似乎决定着双地震带层间距的上下限,其中大陆型上覆板块所对应的双地震带层间距小于20 km;而海洋型对应DSZ层间距则大于15 km.限于现有的观测条件,本文基于有限样本的统计结果仍需要进一步验证.更多还原

【Abstract】 The correlations among the layer separation,stress pattern of 39 Double Seismic Zones (DSZs)and subduction parameters have been analyzed.Subduction parameters include dynamic (e.g.,plate age,thermal parameter,slab pull),kinematic(e.g.,subduction plate velocity, overriding plate velocity,trench migration velocity,back-arc deformation pattern),geometric (e.g.,shallow dip angle,deep dip angle,subduction length,subduction depth)and the nature of overriding plate.The preliminary results indicated that(i)TypeⅠDSZs are likely to exist in older(>60 Ma)slabs and,the layer separation is correlated with dynamic parameters such as plate age,thermal parameter and slab pull;whereas(ii)TypeⅡDSZs are detected mostly in younger(<60 Ma)slabs and,the features are controlled not only by dynamic factors but also local stress regime;(iii)TypeⅠDSZs exist in slabs with thermal parameter greater than 5000 km, whereas both TypeⅠandⅡDSZs exist in slabs with thermal parameter less than 5000 km;(iv) the nature of the upper plate seems to be a controlling factor on the limit of the layer separation, which is 20 km for continental plates while 15 km for oceanic ones.Constrained by the observational condition,the inference from our results based on limited samples need validation from more observations as well as numerical simulations.更多还原