青藏高原现代地壳运动与活动断裂带关系的模拟实验

Numerical simulation of the recent crust movement and the fault activities in Tibetan Plateau

本文以GPS观测、大地热流测量、较高精度地形数据、全球板块相对运动的REVEL模型为基础,建立了以青藏高原现代构造活动为主要研究对象的东亚地区构造形变场有限元模型.数值模拟结果显示,青藏高原内部和周边地区走滑断裂带的活动对东亚地区地壳运动速率和方向有较大的影响,特别是对青藏高原物质向东南方向运动有显著影响;不同构造块体岩石圈强度的差异直接影响了川滇菱形地块边界断层错动性质.在考虑青藏高原地形附加重力作用和周边板块汇聚作用对现今大型断裂带运动特征控制作用的同时,岩石圈之下的橄榄岩软流圈至转换带物质对流对岩石圈的拖曳力也是必须考虑的底部边界条件.

Making use of recent GPS data, heat flow data, elevation data, tectonic stress data, REVEL model of global plate movement, the thin-shell finite element model is adopted to study the recent tectonic activity of Tibetan Plateau. A set of computational experiments show that the existence of the active strike-slip faults is one of the major controlling factors on the eastern and southeasternward movement of the Tibetan crust material. The best numerical simulation result of the movement style of Sichuan-Yunnan tectonic block is obtained with the difference of tectonic blocks＇ strength. The best models suggest that the topographic stress and the convergence forces of the adjacent plate are controlling factors on the active faults in Tibetan Plateau, and the drag force under the lithosphere caused by the convection of the asthenosphere material also plays an important role as the boundary condition of the model.