鄂尔多斯块体北缘Pn波层析成像研究  

Pn Velocity Tomography around the Northern Ordos Block

作　　者：宋晓燕[1] 张建中[1] 王鑫[1] 张帆[1] SONG Xiaoyan;ZHANG Jianzhong;WANG Xin;ZHANG Fan(Earthquake Agency of Inner Mongolia Autonomous Region,80 Jirem Road,Hohhot 010010,China)

机构地区：[1]内蒙古自治区地震局

出　　处：《大地测量与地球动力学》2020年第1期35-38,共4页Journal of Geodesy and Geodynamics

基　　金：内蒙古自治区地震局局长基金重点课题(2018ZD04);中国地震科学台阵探测-华北地区中部资助项目(DQJB16A0302)~~

摘　　要：基于鄂尔多斯块体北缘2008~2018年台网数字化波形记录,利用Pn波层析成像技术获得研究区高精度的上地幔速度结构与各向异性。结果表明,研究区上地幔顶部Pn波速度存在明显的横向不均匀性,且与研究区构造活动及地震分布密切相关;河套断陷带各向异性快波方向呈近EW向。研究区多数历史强震发生在低速异常区或高低速异常过渡带上,该结果为理解研究区地震发生的相关性提供了新的地震学依据。In this paper,we manually pick the high-quality Pn-wave arrival times from the waveform data recorded at the digital seismic networks in the northwest Ordos block from 2008 to 2018,make use of the Pn velocity tomography,and we get the Pn velocity and anisotropy image in the uppermost mantle around the region.The results show that obvious lateral heterogeneities exist in the uppermost mantle of the region,which shows the close correlations to regional tectonics and earthquakes.The fast direction of anisotropy is nearly along the E-W direction around the Hetao graben.Most strong historic earthquakes in the region occur in the low velocity areas or the high-to-low velocity transition zone.These results provide important seismological clues to understand the dynamic problems related to the strong earthquakes.

关 键 词：鄂尔多斯块体北缘 PN波 各向异性 上地幔顶部 

分 类 号：P315[天文地球—地震学]