郑晨^1,,
丁志峰^1,2,,,
宋晓东^3,4
1. 中国地震局地球物理研究所, 北京 100081
2. 中国地震局地震观测与地球物理成像重点实验室, 北京 100081
3. Department of Geology, University of Illinois at Urbana-Champaign, IL 61820, USA
4. 武汉大学测绘学院, 武汉 430079

基金项目: 中国地震局地球物理研究所基本科研业务专项（DQJB16B16），地震行业专项（201308011）及国家自然科学基金（41774061，41474088）联合资助


详细信息

作者简介: 郑晨, 男, 1989年生, 博士, 主要从事地球内部结构方面的研究.E-mail:zhengchen@cea-igp.ac.cn

通讯作者: 丁志峰, 男, 1962年生, 研究员, 主要从事地震学、地球内部结构及动力学研究.E-mail:dingzf@cea-igp.ac.cn

中图分类号: P315

收稿日期:2017-08-30
修回日期:2017-09-20
上线日期:2018-04-05

Joint inversion of surface wave dispersion and receiver functions for crustal and uppermost mantle structure beneath the northern north-south seismic zone

ZHENG Chen^1,,
DING ZhiFeng^1,2,,,
SONG XiaoDong^3,4
1. Institute of Geophysics, China Earthquake Administration, Beijing 100081, China
2. Key Laboratory of Seismic Observation and Geophysical Imaging, China Earthquake Administration, Beijing 100081, China
3. Department of Geology, University of Illinois at Urbana-Champaign, IL 61820, USA
4. School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, China


More Information

Corresponding author: DING ZhiFeng,E-mail:dingzf@cea-igp.ac.cn

MSC: P315

--> Received Date: 30 August 2017
Revised Date: 20 September 2017
Available Online: 05 April 2018


摘要
摘要:通过对南北地震带北段区域所布设的676个流动地震台站观测资料进行处理，联合反演面波频散与接收函数数据，获得了研究区内地壳厚度、沉积层厚度的分布情况以及地壳上地幔高分辨率S波速度结构成像结果.反演结果显示研究区地壳厚度从青藏高原东北缘向外总体逐渐变薄，秦岭造山带地壳厚度较同属青藏高原东北缘的北祁连块体明显减薄；鄂尔多斯盆地及河套盆地分布有非常厚的沉积层，阿拉善块体部分区域也有一定沉积层分布，沉积层与研究区内盆地位置较为一致；松潘—甘孜块体、北祁连造山带等青藏高原东北缘总体表现为S波低速异常；在中下地壳，松潘—甘孜块体下方的低速体比北祁连造山带下方的低速体S波速度值更小、分布深度更浅，更有可能对应于部分熔融的地壳；鄂尔多斯盆地在中下地壳以及上地幔内有着较大范围的高速异常一直延伸到120 km以下，而河套盆地地幔只在80 km以上部分有着高速异常的分布，此深度可能代表了河套盆地的岩石圈厚度，来自深部地幔的热物质上涌造成了该区域的岩石圈减薄；阿拉善块体在地壳和上地幔都表现出高低速共存的分布特征，暗示阿拉善块体西部岩石圈可能受青藏高原东北缘的挤压作用发生改造.
关键词: 联合反演/
面波频散/
接收函数/
南北地震带/
青藏高原东北缘

Abstract:We analyze the observational data recorded by the 676 temporary seismic stations deployed in the northern north-south seismic zone. Our purpose is to derive the crustal thickness, sedimentary thickness and a high-resolution shear wave velocity model of the crustal and uppermost mantle structure beneath the research area. The results demonstrate that the crustal thickness becomes thinner from the northeastern Tibetan Plateau to its periphery, and that in the Qinling orogen is thinner than the northwestern Qilian orogen, implying the former probably has experienced thinning. The Ordos and Hetao basins seem to have very thick sediments, so do some parts of the Alxa block. The sedimentary thickness is consistent with the distribution of basins in the study area. The 3-D shear wave velocity model shows that the northeastern Tibetan Plateau, including the Songpan-Garzê block and northwestern Qilian orogen, is characterized by relatively low velocity anomalies. In the middle crust, the low-velocity zone (LVZ) beneath the Songpan-Garzê block has a lower shear wave velocity and a shallower depth than that beneath the northwestern Qilian orogen, which may suggest partial melting in the Songpan-Garzê block. A significantly high velocity anomaly that extends downward at least 120 km is observed beneath the Ordos basin, while the high velocity anomaly below the Hetao basin extends downward 80 km, revealing a thinned lithosphere beneath the Hetao basin presumably associated with deep hot mantle materials. The Alxa block is characterized by the coexistence of low and high velocity anomalies, suggesting that the lithosphere beneath the western Alxa block may have been deformed by the expansion of the northeastern Tibetan Plateau.
Key words:Joint inversion/
Surface wave dispersion/
Receiver function/
South-North Seismic Zone/
Northeastern Tibetan Plateau



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