Crustal Deformation in the India-Eurasia Collision Zone From 25Years of GPS Measurements
Crustal Deformation in the India-Eurasia Collision Zone From 25Years of GPS Measurements
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25 年 GPS 测量显示印度-欧亚大陆碰撞区的地壳变形
DOI：
10.1002/2017jb014465
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发表时间：
2017
影响因子：
3.9
通讯作者：
Wei Na
中科院分区：
文献类型：
--
作者：
Zheng Gang;Wang Hua;Wright Tim J;Lou Yidong;Zhang Rui;Zhang Weixing;Shi Chuang;Huang Jinfang;Wei Na
印度-欧亚碰撞带是地球上最大的变形区域；全球定位系统（GPS）对现今变形的直接测量有可能区分不同的大陆构造模型。但是，不断提高的空间分辨率和观测精度只会导致竞争模式的实现越来越复杂。在这里，我们提供了印度-欧亚大陆最完整、最准确和最新的速度场，包括1991-2015年期间测量的2576个速度。我们的速度场的核心来自中国地壳运动观测网- I/II：自1999年以来连续观测的27个站点；1998-2007年期间每年观察56个竞选站；1999年、2001年、2004年和2007年共观测了1000个竞选站；自2010年底以来连续运行的站点有260个；2009年、2011年、2013年和2015年分别观察了2000个竞选站。我们对这些数据进行处理，并将解决方案与全球应变率模型汇编中的站点在一致的参考框架中结合起来，然后反演连续速度和应变率场。我们更新了主要断层的大地测量滑动率（有些沿走向变化），并发现沿西藏主要走滑断层的滑动率与最近的地质估计非常吻合。速度场显示出几个大的不变形区，应变集中在一些主要断层周围，扩散应变区和高原的扩张。我们建议需要新一代包含强度变化和应变弱化机制的动态模型来解释关键观察结果。不仅仅是在主要断层附近，该地区大部分地区的地震危险性都在上升。
The India‐Eurasia collision zone is the largest deforming region on the planet; direct measurements of present‐day deformation from Global Positioning System (GPS) have the potential to discriminate between competing models of continental tectonics. But the increasing spatial resolution and accuracy of observations have only led to increasingly complex realizations of competing models. Here we present the most complete, accurate, and up‐to‐date velocity field for India‐Eurasia available, comprising 2576 velocities measured during 1991–2015. The core of our velocity field is from the Crustal Movement Observation Network of China‐I/II: 27 continuous stations observed since 1999; 56 campaign stations observed annually during 1998–2007; 1000 campaign stations observed in 1999, 2001, 2004, and 2007; 260 continuous stations operating since late 2010; and 2000 campaign stations observed in 2009, 2011, 2013, and 2015. We process these data and combine the solutions in a consistent reference frame with stations from the Global Strain Rate Model compilation, then invert for continuous velocity and strain rate fields. We update geodetic slip rates for the major faults (some vary along strike), and find that those along the major Tibetan strike‐slip faults are in good agreement with recent geological estimates. The velocity field shows several large undeforming areas, strain focused around some major faults, areas of diffuse strain, and dilation of the high plateau. We suggest that a new generation of dynamic models incorporating strength variations and strain‐weakening mechanisms is required to explain the key observations. Seismic hazard in much of the region is elevated, not just near the major faults.