Stress and relaxation time in the viscoelastic lithosphere inferred from the outer topographic rise
Stress and relaxation time in the viscoelastic lithosphere inferred from the outer topographic rise
复制标题
从外部地形上升推断的粘弹性岩石圈中的应力和松弛时间
DOI：
10.1029/jb089ib05p03211
复制
发表时间：
1984
影响因子：
--
通讯作者：
Y. Ida
中科院分区：
文献类型：
--
作者：
Y. Ida
粘弹性薄板的变形通常是用一个方程来分析的，而这个方程是人为地假定泊松比等于1/2的。本文指出，通过引入一个新的变量来表示板的顶部和底部之间的压力梯度，可以对任意泊松比的值进行简单的处理。在这种处理方法中，运动板的一维定常变形由一个简单的解析方程给出。利用该方程分析了深海海沟外地形向海上升的测深问题。分析表明，西太平洋海沟的岩石圈受到100兆帕或更大的伸展水平力。东太平洋海沟的水平力可能要小得多，甚至是压缩的。为了防止水平力和弯曲应力过大，板的麦克斯韦松弛时间必须为1英里。或更短，有效粘度必须为1024PaS或更低。
The deformation of a thin viscoelastic plate is usually analyzed by use of an equation that is derived with an artificial assumption of the Poisson's ratio equal to 1/2. It is shown in this paper that a simple treatment applicable to an arbitrary value of Poisson's ratio is possible by introducing a new variable that represents the pressure gradient between the top and bottom of the plate. In this treatment a one-dimensional stationary deformation of moving plate is given by a simple analytic equation. This equation is used to analyze the bathymetry of the outer topographic rise seaward of the deep-sea trenches. The analysis reveals that the lithosphere in the western Pacific trenches is subject to an extensional horizontal force of 100 MPa or greater. The horizontal force may be much less or even compressive in the eastern Pacific trenches. To prevent horizontal force and bending stress from being extraordinarily large, the Maxwell relaxation time of the plate must be 1 m.y. or shorter, and the effective viscosity must be 1024 Pa s or less.