[关键词]
[摘要]
中国大陆的构造变形主要与印度和欧亚两大板块的碰撞有关。印度板块的北向推挤直接导致了世界上最宽旷、最活跃和最复杂的现今构造变形。GPS观测技术问世前,构造变形的定量化研究主要依赖活断层的形貌勘察和区域强震的震源机制解,其结果准确度不足且时空界限模糊。1988年中国地震局在滇西地震实验场首次开展GPS形变监测实验,后又经历国家“攀登项目”、“首都圈GPS地形变监测网”等诸多项目实践,直到“九五”重大科学工程“中国地壳运动观测网络”成功建成,中国大陆现今变形图像才逐步完整和清晰。特别是近年基于“中国构造环境监测网络”2000多站点及近30年累积的其他数据,一个覆盖中国大陆且衔接边邻、框架统一、毫米/亚毫米精度的速度场构建完成。这一基础图像对揭示中国大陆活动构造的运动学和动力学特征、深入研究青藏高原及其周边地区构造形成与演化提供了强有力的观测约束,也为地震危险性的定量化分析奠定了坚实基础。
[Key word]
[Abstract]
Tectonic deformation in continental China is mainly associated with collision between the Indian and Eurasian plates. Northward indentation of the Indian plate has resulted in a continental deformation belt which is the most active,complex,and broad in the world. Prior to GPS technology,research of tectonic deformation relied mainly on geomorphic investigation of active faults and focal mechanism solutions of strong earthquakes associated with the fault ruptures,which were not so accurate and lacked sufficient spatio-temporal resolution. The very first experiment of using GPS to monitor crustal deformation was conducted by the China Earthquake Administration in 1988,followed by the national “Pandeng” project,and the “Capital Circle” project,etc. Not until the foundation and execution of the “Crustal Movement Observation Network of China”,which is the big science project of the ninth five-year plan,deformation pattern of continental China has then become clear. GPS data from more than 2000 sites have been collected in recent years by the “Tectonic and Environmental Monitoring Network”,which,combined with other data accumulated over the last 30 years,is capable of producing a unified high resolution velocity field covering continental China and its vicinity and with millimeter/sub-millimeter precision. This fundamental product helps to characterize kinematics of tectonic deformation and to study its dynamic property and process for continental China. It also provides critical constraints for the study of tectonic formation and evolution of the Tibetan Plateau and its vicinity,and lays strong foundation for the quantification of earthquake potential and mitigation of seismic hazard in the region.
[中图分类号]
P315
[基金项目]
国家自然科学基金(41474028、41774008)资助