Investigating the Partitioning of Vertical Strength within the India-Eurasia Lithosphere using Surface Observations: A Numerical Modeling Approach

板块构造理论在地球物理学领域是革命性的，它解释了板块的运动以及地震和火山的位置。 然而，这一理论在地震延伸1000？s公里和显著地形创建。 印度板块和欧亚板块的不断碰撞为研究这些地区和控制大陆碰撞带变形模式的因素提供了一个天然实验室。 在没有直接采样的岩石圈与深度，数值模拟可以提供物理上允许的岩石圈属性的界限。 了解大陆岩石圈内强度的变化对于评估产生地震和建造山脉的力量至关重要。 该方案所获得的结果将对青藏高原变形力、岩石圈内的应力传递、地表观测对岩石圈性质取样的深度、上地壳、下地壳和岩石圈地幔之间的强度分配、藏南下印度板块的影响、本项目将通过三维地球动力学模拟来求解Stokes流，研究欧亚大陆岩石圈内的横向和垂直强度变化。 地球物理观测将用于构建印度-欧亚碰撞区的物理精确模型体积，并将进行数值模拟，以确定岩石圈强度（垂直和横向）变化对预测的地表变形的影响。 预测的表面速度和观测到的表面变形场之间的比较，由GPS和第四纪断层滑动数据的约束，将区分物理上可行的模型。 这项工作将力求：（1）确定欧亚大陆变形岩石圈内允许的垂直强度差;（2）分离欧亚大陆内地表观测的深度敏感性;（3）研究岩石圈厚度变化和地幔流动对观测到的地表形变场的影响。

The theory of plate tectonics was revolutionary in the field of geophysics and explained the motion of plates and locations of earthquakes and volcanoes. However, this theory breaks down at continental boundaries where earthquakes extend 1000?s of km and significant topography is created. The ongoing collision of the Indian and Eurasian plate provides a natural laboratory for studying such regions and the factors controlling deformation patterns in continental collisional zones. In the absence of direct sampling of the lithosphere with depth, numerical modeling can provide bounds on physically allowable lithospheric properties. Understanding the variation in strength within the continental lithosphere is fundamental to assessing the forces that generate earthquakes and build mountains. Results obtained within this proposal will have important implications relating to forces generating deformation of the Tibetan Plateau, stress transfer within the lithosphere, the depth to which surface observations sample lithospheric properties, partitioning of strength between upper crust, lower crust and lithospheric mantle, influence of the lower Indian plate beneath southern Tibetan, and flow the base of the lithosphere resulting from convection of the interior of the Earth.This project will perform 3-D geodynamic modeling solving Stokes flow to investigate the lateral and vertical strength variations within the Eurasian lithosphere. Geophysical observations will be used to construct a physically accurate model volume of the India-Eurasian collision zone, and numeric simulations will be performed to determine the effects of variations in lithospheric strength (both vertically and laterally) on predicted surface deformation. Comparisons between predicted surface velocities and the observed surface deformation field, constrained by GPS and quaternary fault slip data, will differentiate between physically viable models. This work will seek to: (1) Map out the allowable vertical strength contrasts within the Eurasian deforming lithosphere; (2) Isolate the depth sensitivity of surface observations within Eurasia; (3) Investigate the influence of variable lithospheric thickness and mantle flow on the observed surface deformation field.