Stress concentration in the upper lithosphere caused by underlying visco-elastic creep
Stress concentration in the upper lithosphere caused by underlying visco-elastic creep
复制标题
由底层粘弹性蠕变引起的上部岩石圈应力集中
DOI：
10.1016/0040-1951(77)90119-6
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发表时间：
1977
期刊：
影响因子：
2.9
通讯作者：
M. Bott
中科院分区：
文献类型：
--
作者：
N. Kusznir;M. Bott
用有限元法研究了岩石圈划分为上弹性层和下粘弹性层的意义。在岩石圈板端部施加均匀的水平边界应力，导致弹性层中的应力放大，放大系数约等于岩石圈厚度与弹性层厚度之比，粘弹性层除了在其端部附近几乎没有应力。接近平衡的时间常数与粘度成正比，在我们的模型中，1023 N s m−2时的粘度为0.21 My，并且伴随着岩石圈的挠曲。弹性层厚度的局部变化导致应力的反向变化，部分解释了屏蔽区的稳定性和热高原隆起区的构造活动。它表明，应力放大也发生在应力产生的体力，如差异加载和均衡补偿大陆边缘。
The implications of subdividing the lithosphere into upper elastic and lower viscoelastic layers are investigated by finite-element analysis. Application of uniform horizontal boundary stresses at the ends of a lithospheric plate leads to amplification of the stress in the elastic layer by a factor about equal to the ratio of lithospheric to elastic layer thicknesses, and the visco-elastic layer becomes nearly stress-free except near its ends. The time constant for approach to equilibrium is proportional to viscosity, being for our model 0.21 My for 1023N s m−2, and there is some accompanying flexure of the lithosphere. Local variation in the thickness of the elastic layer causes inverse variation in the stress, in part explaining the stability of shield regions and the tectonic activity of hot plateau uplift regions. It is shown that stress amplification also occurs where the stresses arise from body forces such as differential loading and isostatic compensation across continental margins.