Strain partitioning is a common process at obliquely convergent plate margins dividing oblique convergence into margin-normal slip on the plate-bounding fault and horizontal shearing on a strike-slip system parallel to the subduction margin. In subduction zones, strain partitioning in the upper continental plate is mainly controlled by the shear forces acting on the plate interface and the strength of the continental crust. The plate interface forces are influenced by the subducting plate dip angle and the obliquity angle between the normal to the plate margin and the convergence velocity vector, and the crustal strength of the continent is strongly affected by the presence or absence of a volcanic arc, with the presence of the volcanic arcs being common at steep subduction zones. Along the∼7000 km western margin of South America the convergence obliquity, subduction dip angles and presence of a volcanic arc all vary, but strain partitioning is only observed along parts of it. This raises the questions, to what extent do subduction zone characteristics control strain partitioning in the overriding continental plate, and which factors have the largest influence?

中文翻译：

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对北安第斯倾斜俯冲带上方大陆应变分区的控制

应变划分是斜会聚板块边缘的一个常见过程，将斜会聚分为板块边界断层上的边缘-正常滑动和平行于俯冲边缘的走滑系统上的水平剪切。在俯冲带中，上大陆板块的应变分配主要受作用于板块界面的剪切力和大陆地壳强度的控制。板块界面力受俯冲板块倾角和板块边缘法线倾角与辐合速度矢量的影响，大陆地壳强度受火山弧存在与否影响较大，火山弧的存在在陡峭的俯冲带很常见。沿着南美洲约 7000 公里的西缘，辐合倾角、俯冲倾角和火山弧的存在都各不相同，但仅在部分地区观察到应变分区。这就提出了一个问题，俯冲带特征在多大程度上控制了上覆大陆板块的应变分区，哪些因素影响最大？