Earth curvature effects on subduction morphology: Modeling subduction in a spherical setting
Earth curvature effects on subduction morphology: Modeling subduction in a spherical setting
复制标题
地球曲率对俯冲形态的影响：在球形环境中模拟俯冲
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Koumoutsakos
中科院分区：
文献类型：
--
作者：
G. Morra;P. Chatelain;P. Tackley;P. Koumoutsakos
本文介绍了Stokes流的(快速多极)加速边界元方法(Accelerated-BEM)在地球动力学中的首次应用。该方法的优点是计算元素的数量减少，并随问题大小进行线性缩放。结果表明，这种数值方法可以在球坐标下有效地模拟几个行星尺度的地球动力学系统，并提出了一种联合模拟地幔对流和板块构造的一般方法。论文的第一部分致力于对新方法的技术阐述，第二部分侧重于地球曲率对非常宽的大洋岩石圈俯冲(W=6.6万mm和W=9.000 mm)的影响，比较了两种不同的行星半径(ER=6.371万mm，2ER=2.2x×6.371 mm)的影响，对应于一种类似地球的模型(ER)和一种“平坦的地球”模型(2ER)。结果表明，这两种模型有明显的不同：平坦地球上的板块表现出轻微的起伏，而在类似地球的背景下，同一俯冲板块呈现出双重行为，其特征是边缘凹曲，中心以1000公里数量级的波长折叠。
We present the first application in geodynamics of a (Fast Multipole) Accelerated Boundary Element Method (Accelerated-BEM) for Stokes flow. The approach offers the advantages of a reduced number of computational elements and linear scaling with the problem size. We show that this numerical method can be fruitfully applied for the simulation of several geodynamic systems at the planetary scale in spherical coordinates, and we suggest a general approach for modeling combined mantle convection and plate tectonics. The first part of the paper is devoted to the technical exposition of the new approach, while the second part focuses on the effect played by Earth curvature on the subduction of a very wide oceanic lithosphere (W = 6,000 km and W = 9,000 km), comparing the effects of two different planetary radii (ER = 6,371 km, 2ER = 2 × 6,371 km), corresponding to an "Earth-like" model (ER) and to a "flat Earth" one (2ER). The results show a distinct difference between the two models: while the slab on a "flat Earth" shows a slight undulation, the same subducting plate on the "Earth-like" setting presents a dual behavior characterized by concave curvature at the edges and by a folding with wavelength of the order of magnitude of 1,000 km at the center of the slab.