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目前解释青藏高原东缘的生长与扩张有诸多动力学模型,如:刚性块体挤出模型、连续变形和中下地壳流模型。由于受到岩石层结构模型分辨率的限制,青藏高原演化和变形的动力学过程仍不清楚。我们利用最新布设在青藏高原东南缘的地震台阵,通过接收函数和瑞利波联合反演得到了该区高分辨率三维岩石层横波速度模型,更好地揭示了壳内低速带(LVZ)分布特征。我们的速度模型显示研究区壳内存在两个低速通道,这两个低速通道边界与该区主要走滑断裂相对应,且沿着东喜马拉雅构造结顺时针分布,这与该区地壳物质顺时针运动模式比较一致。此外,我们观测到该区域主要大地震分布在这两个低速通道边界区域。据此,我们提出塑性流动和剪切变形在青藏高原的隆升和变形过程中都起了重要作用。
At present, there are many dynamic models to explain the growth and expansion of the eastern edge of the Qinghai-Tibet Plateau, such as rigid block extrusion model, continuous deformation and middle-lower crust flow model. Due to the limitation of lithospheric model resolution, the dynamics of the evolution and deformation of the Tibetan Plateau are still not clear. Using the latest seismic array arrayed on the southeast margin of the Qinghai-Tibet Plateau, we obtained the high-resolution three-dimensional shear-wave velocity model of the lithosphere by using the receiver function and Rayleigh wave joint inversion, revealing that the low velocity zone (LVZ) Distribution characteristics. Our velocity model shows that there are two low-velocity channels in the crust of the study area. The boundaries of these two low-velocity channels correspond to the main strike-slip faults in this area and are distributed clockwise along the East Himalayan structural knot. This is consistent with the fact that the crustal material in this area is clockwise Exercise patterns more consistent. In addition, we observed that the major earthquakes in the region were distributed over the boundary between the two low-speed lanes. Accordingly, we propose that both plastic flow and shear deformation play an important role in the uplift and deformation of the Qinghai-Tibet Plateau.