付媛媛^1,2,,
肖卓³
1. 中国地震局地震预测研究所, 北京 100036
2. 中国地震局地震预测研究所地震预测重点实验室, 北京 100036
3. 中国科学院广州地球化学研究所, 广州 510640

基金项目: 国家自然科学基金项目（41574042），中国地震局地震预测研究所基本科研业务费专项（2019IEF0705）及中国科学院广州地球化学研究所所长基金（2019SZJJ-05）资助


详细信息

作者简介: 付媛媛, 女, 1980年生, 研究员, 主要从事地震各向异性及速度成像方面研究.E-mail:fuyuanies@163.com

中图分类号: P315

收稿日期:2019-06-05
修回日期:2020-01-07
上线日期:2020-03-05

Ambient noise tomography of Rayleigh and Love wave in Northeast Tibetan plateau and adjacent regions

FU YuanYuan^1,2,,
XIAO Zhuo³
1. Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China
2. Key Laboratory of Earthquake Prediction, Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China
3. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China


MSC: P315

--> Received Date: 05 June 2019
Revised Date: 07 January 2020
Available Online: 05 March 2020


摘要
摘要:基于青藏高原东北缘及邻区流动密集地震台阵——喜马拉雅二期2013年12月至2015年8月期间的三分量连续波形数据，采用背景噪声成像方法获得了Rayleigh波周期为6~30 s和Love波6~25 s的二维相速度.6~12 s Rayleigh和Love波相速度在鄂尔多斯盆地及银川—河套地堑呈现明显的低速异常，而在西秦岭造山带和中亚造山带则显示高速异常.16~25 s的相速度同时受中下地壳及上地幔顶部速度结构和地壳厚度影响.此周期范围内，位于青藏高原的祁连地块和松潘甘孜地块北部呈现大范围相速度低速异常，青藏高原周边的鄂尔多斯和西秦岭造山带表现为高速异常.青藏高原与周边块体相速度的横向不均匀性，可能反映了构造活动或者地壳厚度的差异.此外，中亚造山带在周期16~20 s时，Rayleigh波相速度高低相间，但Love波大范围高速异常，两者差异可能反映了径向各向异性的影响.
关键词: 青藏高原东北缘/
背景噪声/
Rayleigh波/
Love波

Abstract:We obtain the 2D phase velocity of Rayleigh (6~30 s) and Love (6~25 s) waves in the northeastern margin of the Tibetan plateau and adjacent regions using the seismic ambient noise recorded by the dense temporary seismic network (ChinArray Π) from December 2013 to August 2015. The Rayleigh and Love wave phase speed maps at short periods (6~12 s) show clear correlations with major geological structures. The Ordos Basin and Yinchuan-Hetao rift show obvious low velocity, while the mountains (West Qinling Orogen and Central Asian Orogenic Belt) have high phase velocity. However, with the increasing of the period, the Ordos Basin gradually changes into high velocity, and the Qilian Orogenic Belt and northern Songpan-Garzê Terrain exhibit broad low velocity zones. This indicates the tectonic difference between the Tibetan plateau and adjacent regions. Rayleigh and Love wave phase velocity maps at the same period reveal various features at the Central Asian Orogenic Belt from the period 16 s to 20 s. Such difference could be attributed to the presence of radial anisotropy.
Key words:Northeastern Tibetan Plateau/
Ambient noise/
Rayleigh wave/
Love wave



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