摘要
青藏高原东北缘是青藏高原隆升的前缘地带,其构造变形特征一直是研究的热点。前人在该区域进行过面波成像研究,但不同结果存在较明显的差异,可能与不同成像方法的分辨率有关,此次研究分别使用基于射线的方法和基于程函方程的方法进行了瑞利波相速度成像。笔者对比了20 s、30 s和60 s的成像结果,两种方法的结果表现出相似的速度特征。总体的速度特征与研究区域的主要构造单元分布相吻合,青藏高原东北缘表现出低速异常,鄂尔多斯块体表现出高速异常。在银川河套地堑,基于程函方程的成像在20 s和30 s得到更明显的低速异常,低速异常体的分布与地堑的轮廓吻合更好,说明基于程函方程的方法对数据利用更充分。
The Northeastern margin of the Tibetan Plateau is under ongoing uplifting,whose tectonic structures have always been a research hotspot.Previous studies of surface wave tomography in this region show significant differences,which may be related to different tomography methods.We performed Rayleigh wave phase velocity tomography using both ray-theory and Eikonalequation methods in this study.We compared the tomography results of 20 s,30 s and 60 s obtained from the two methods which showed relatively consistent velocity features.The overall velocity characteristics are consistent with the distribution of main structural units in the study area.The Northeastern of the Tibetan Plateau shows a low velocity anomaly,while the Ordos Block shows a high velocity anomaly.In the Yinchuan-Hetao Graben,Eikonal-equation based tomography shows more obvious low velocity anomalies in 20 s and 30 s,and the distribution of low velocity anomalies is better consistent with the contour of the graben,indicating that the Eikonal-equation based tomography can make use of the data more sufficiently.
作者
郝识杰
黄周传
王良书
徐鸣洁
米宁
于大勇
HAO Shijie;HUANG Zhouchuan;WANG Liangshu;XU Mingjie;MI Ning;YU Dayong(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China)
出处
《高校地质学报》
CAS
CSCD
北大核心
2020年第6期712-720,共9页
Geological Journal of China Universities
基金
自然科学基金项目(41674044,41674049)
中国地震科学台阵探测项目(DQJB16A0306)联合资助。
关键词
青藏高原东北缘
岩石圈结构
面波成像
瑞利波相速度
Northeastern Tibetan Plateau
lithospheric structure
surface wave tomography
rayleigh wave phase velocity
