中国东北诺敏河火山群地区面波层析成像研究  

Study on surface wave phase velocity tomography beneath the Nuomin River volcanoes in Northeast China

作　　者：侯颉 吴庆举[1] 余大新[2] 叶庆东[2] HOU Jie;WU QingJu;YU DaXin;YE QingDong(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]中国地震局第一监测中心,天津300180

出　　处：《地球物理学报》2022年第6期2090-2106,共17页Chinese Journal of Geophysics

基　　金：国家自然科学基金(41474074和41504073)资助。

摘　　要：本文利用诺敏河火山群地区的43个宽频带流动地震台在2015年6月至2017年5月记录到的垂直向连续数据,采用基于连续小波变换的频率-时间分析技术采集了6475条高质量的基阶相速度频散曲线,用面波成像方法反演研究区地壳和上地幔三维S波速度结构.结果表明:诺敏河火山20~30 km深度的中、下地壳范围内观测到一个小尺度低速异常,推测为诺敏河火山群地壳岩浆房,其与五大连池火山群地壳岩浆房在横向上不相通;研究区上地幔40~150 km深度范围内存在多个局部高速异常,且这些高速异常之上均出现明显的低速异常,这种结构模式暗示了这些区域可能发生了岩石圈拆沉作用,推测不同深度的高速异常可能是不同地质时期拆沉的岩石圈地幔及其残留;诺敏河火山群东南侧存在上下连通的低速异常,其从研究区东南部150 km深度左右向北连通研究区地壳减薄区域以及诺敏河火山群在地表的出露位置,表明这些位置可能存在上升的软流圈物质,且上升方向和小古里河—科洛—五大连池—二克山火山带延展方向基本一致,结合前人的研究结果分析,暗示存在诺敏河和五大连池火山群深部同源的可能性.Based on the vertical continuous records of 43 broadband mobile seismic stations in the Nuomin River volcanoes from June 2015 to may 2017,6475 high-quality phase velocity dispersion curves were acquired by using frequency time analysis technique.Then,the 3D S-wave velocity structure of the crust and upper mantle in the study area is inversed by using the surface wave imaging method.Results show a small-scale low velocity anomaly was observed in the middle and lower crust at the depth of 20~30 km of the Nuomin River volcanoes,which is speculated to be the crustal magma chamber of the Nuomin River volcanoes,and is not connected with the crustal magma chamber of the Wudalianchi volcanoes in the transverse direction.There are several local high velocity anomalies within the depth range of 40~150 km in the upper mantle of the study area,and obvious low velocity anomalies appear above these high velocity anomalies.This structural model suggests that lithospheric delamination may have occurred in these areas.It is speculated that the high velocity anomalies at different depths may be lithospheric delamination and its residues in different geological periods.There is a low velocity anomaly connecting up and down in the southeast of the Nuomin River volcanoes,which connects the crustal thinning area of the study area,the exposed positon of Nuomin River volcanoes and the depth below 150 km in the southeast of the study area,indicating that there may be rising asthenosphere materials at these positions,and the rising direction is basically consistent with the extension direction of Xiaogulihe-Kelou-Wudalianchi-Erkeshan volcanic belt.Combined with the analysis of previous research results,it is suggested that there is the possibility of deep homology between the Nuomin River and the Wudalianchi volcanoes.

关 键 词：诺敏河火山群 岩石圈拆沉 火山活动 面波层析成像 S波速度结构 

分 类 号：P315[天文地球—地震学]