欧亚板块区域性地壳形变研究

题名	欧亚板块区域性地壳形变研究
作者	李春晓
学位类别	硕士
答辩日期	2014-04
授予单位	中国科学院研究生院（云南天文台）
授予地点	北京
导师	熊耀恒
关键词	全球板块运动 NNR-MORVEL56 ITRF2008 球面多边形转动惯量张量中国区域块体运动应变率速度梯度张量场
其他题名	Crustal Movement Within the Eurasian Plate
学位专业	天体测量与天体力学
中文摘要	随着人们进入 21 世纪，由于人口的快速增长迫使有限的地球资源面临着更大的压力，为了更好地理解我们不断变化的星球，地球科学家们承担着越来越多的责任。考虑到大多数的地震和火山喷发多发生在板块的交界地带，发展一个可以解释地球动力学机制的理论十分必要。在过去的 50 年间，大量关于板块构造的理论已经形成，基于这些理论，板块的运动模型共分为 2 种，第一种模型主要是基于地质测量数据而建立起来的，第二种则为利用空间大地测量观测数据建立的运动模型。为了阐释现今地球表面上板块的运动，本文主要用了 GPS 观测数据来计算板块的运动参数。本文用 ITRF2008 参考架下的 225 个 GPS 测站估计了 NNR-MORVEL56 板块运动模型下的 13 个主要板块的运动参数，包括 Amurian 板块、Antractic 板块、Arabia 板块、Australia 板块、Eurasia 板块、India 板块、N.America 板块、Nazca 板块、Nubia 板块、Paci?c 板块、S.America 板块、Somalia 板块和 Sundaland 板块。本文采用了与传统的测站筛选准则不同的方法来进行测站的筛选，从而避免了测站距离多远才算位于刚性板块内部的主观性，即根据全球应变率模型（GSRMv1.2），第二不变应变率大于 10^?14/yr 的测站予以剔除。另外一个不同点在于，本文应用了 ICE3G-VM2 模型，计算了测站受冰期回弹影响而对测站产生的附加垂向速度和水平速度，若测站产生的附加水平速度超过 0.5mm/yr ，则这些测站将被剔除。最后，本文采用的参考模型为 2010 年最新发布的全球板块运动模型 NNR-MORVEL56，而没有采用相对较旧的 1994 年发行的模型 NNR-NUVEL1A。为了推导板块的绝对运动模型，板块的转动惯性张量作为独立的几何量是不可或缺的。在估计完 13 个板块运动的欧拉矢量后，本文计算了 56 个板块的几何参数，包括板块的面积和 6 个转动惯性张量的分量，计算方法主要是基于球面三角形算法和自适应辛普森二维积分方法，计算的结果可以在一定精度范围之内应用于实际中。在得出欧亚板块的运动参数的前提下，利用中国及其周边区域的 329 个 GPS 测站相对于欧亚板块的速度场求解了中国 6 个区域块体相对于欧亚板块的欧拉矢量，包括喜马拉雅-西藏、云南-四川、祁连山-阿拉泰、天山- 塔里木、北中国和南中国活动地块区。同时利用 341 个 GPS 测站的速度场计算了块体内部的形变参数，包括第二不变应变率、自转率、膨胀率、最大剪切应变率、最大拉伸应变率、最大挤压应变率和最大拉伸应变率主方向。本文用计算速度场梯度张量的方法估计了测站和网格节点的应变参数，与以往用均匀应变模型和二阶应变模型的方法不同。本文中所有的结果和结论可以为从事地球动力学研究的学者提供数据分析的支持，并且提供了详细的关于板块运动和板内形变的计算方法，也将是一件非常有意义的事情。
英文摘要	As we enter the 21st century, when the Earth's ?nite resources will be further strained by the explosive population growth, earth scientists are undertaking more and more responsibilities for striving to better understand our dynamic planet. Given that most earthquakes and volcanic eruptions do not strike randomly but occur in speci?c areas, such as along plate boundaries, it is necessary to develop a theory that might be able to explain how our earth works. Over the past ?fty years, a quite few of theories about tectonic plate have been formulated as two distinct types of plate kinematic models, which are based on geological measurements and observations from space geodetic surveying respectively. In order to demonstrate the current motion of these tectonic plates on the surface of our planet, a mass of available GPS observational data have been applied to the calculation of kinematic parameters in this paper. The kinematical parameters for 13 major global plates including Amurian, Antarctic, Arabia, Australia, Eurasia, India, N.America, Nazca, Nubia, Paci?c, S.America, Somalia and Sundaland within NNR-MORVEL56 plate motion model have been estimated in this paper, using the velocities from 225 GPS stations with respect to ITRF2008. Here a di?erent method for determining whether stations are located in a rigid plate has been used, which avoids the di?culties caused by the traditional site selection criteria concerning that how far stations should be away from the plate boundaries. It is of great signi?cance to initiate a new criteria that stations with second invariant strain rate(SISR) greater than 10^?14/yr is supposed to be eliminated, according to the GSRMv1.2(Global Strain Rate Model) delineating the strain rate over the globe. Another improvement in this paper is the application of the ICE3G-VM2 model containing ice model and earth model, where stations with additional horizontal velocity greater than 0.5mm/yr have been ignored instead of modifying a station’s velocity owing to the e?ect of the GIA(Glacial Isostatic Adjustment). Last but not the least,compared with the relatively old-fashioned plate motion model, NNR-NUVEL1A published in the year of 1994, NNR-MORVEL56 that was released in the year of 2010 has been regarded as the primary referenced model in this paper. To derive a absolute plate motion model in a NNR(No-Net-Rotation) reference frame, however, the inertia tensors are always considered as indispensable attribute of all these plates. In this paper, evaluation for the Euler vectors of 13 plates was followed by the computation of the geometric parameters of each plate within NNR-MORVEL56, including the area and 6 components of the inertia tensor. The computational approaches are mainly built on a triangulation algorithm and the adaptive Simpson’s double integral method for spherical polygons, which produces highly reliable results for all 56 modern plates. In addition, the Euler vectors and their uncertainty for the 6 active block regions, including Himalayan-Tibet, Yunnan-Sichuan, Qilian-Altyn, Tianshan-Tarim, North China, and South China were also calculated, using 329 GPS horizontal velocities relative to the background of Eurasia plate, together with the intraplate deformation parameters, containing the second invariant strain rate,rotation rate, delatation rate, the maximum shear strain rate, the principal extensional strain rate(PESR), the principal compressional strain rate, and the principal direction for the PESR, given the 341 GPS horizontal velocities available in the Chinese mainland. When estimating strain rates of stations or grid nodes in a speci?ed plate, a somewhat di?erent method based on the velocity gradient tensor ?eld has been used in this paper, rather than on the calculation for the average strain parameters throughout the whole plate, which used to be based on even strain model and the second order strain model. All of the results and conclusions in this paper may be able to
语种	中文
学科主题	天文学
公开日期	2016-05-03
页码	84
内容类型	学位论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/7360]
专题	云南天文台_应用天文研究组
推荐引用方式 GB/T 7714	李春晓. 欧亚板块区域性地壳形变研究[D]. 北京. 中国科学院研究生院（云南天文台）. 2014.