SGER: An Exploratory Study of Surface Wave Dispersion in the Indian Ocean, Indian Subcontinent and Western China

在印度及其周边地区发现了世界上两个一流的地球物理特征。首先，喜马拉雅和青藏高原是迄今为止地球上最突出的地形；根据所有现有证据，人们知道印度次大陆的北移是导致它形成的根本原因。但是，当次大陆向北移动时，该地区地球内部的地质过程是什么呢？此外，在世界大地水准面图上，印度洋盆地和南印度地区是最大的低异常。这一大地水准面低意味着该地区之下存在相对质量不足，但在什么深度和多大程度上？它为什么会形成？导致它们形成的机制很可能在该地区下方的地壳和地幔中留下了痕迹。因此，对地壳和上地幔的详细测绘是了解这些过程的第一步。直到最近，来自高质量便携式地震台和一个永久网络的数据才开始存在，来自这些网络的数据已经积累到可以进行重大分析的程度。拟议中的工作将与印度海得拉巴国家地球物理研究所(NGRI)的S.S.Rai博士合作进行。我们计划在短期内使用面波成像上地幔(向下至约300公里)结构的横向变化和分辨率。我们的较长期计划是对该地区进行全面的面波层析研究。

Two of the world's first order geophysical features are found in India and its surrounding areas. First, the Himalaya and the Tibetan plateau are by far the most outstanding topography of the Earth; based on all available evidence it is known that the northward motion of the Indian subcontinent is the root cause that led to its formation. But what were the geological processes in the interior of the Earth in this area as the subcontinent plowed northward? Furthermore, in the geoidal map of the world, the Indian Ocean basin and southern India area is marked by the largest low anomaly. This geoidal low implies that there is a relative mass deficiency under the area, but at what depth and how much? Why did it form? The mechanisms that led to their formation most probably left traces in the crust and mantle under this area. A detailed mapping of the crust and upper mantle is therefore the first step toward understanding the processes. Only recently data from high quality portable seismic stations and a permanent network came into existence and data from these networks have accumulated to a degree when significant analyses can be preformed. The proposed work here will be performed in cooperation with Dr. S.S. Rai of National Geophysical Research Institute (NGRI), Hyderabad, India. We plan in the short term to use surface waves to image the lateral variations as well as resolution of upper mantle (down to ~300 km) structures. Our longer-range plan is to conduct a comprehensive surface wave tomographic study of the area.