用户名: 密码: 验证码:
首都圈地区Pb震相典型特征与康拉德界面研究
详细信息    查看全文 | 推荐本文 |
  • 英文篇名:Characteristics of seismic phase Pb and the Conrad interface beneath the Capital Circle region around Beijing
  • 作者:林向东 ; 袁怀玉 ; 李稳 ; 杨选 ; 牟磊育 ; 赵桂儒 ; 孙海霞 ; 侯丽娟 ; 武敏捷 ; 董非非
  • 英文作者:LIN XiangDong;YUAN HuaiYu;LI Wen;YANG Xuan;MU LeiYu;ZHAO GuiRu;SUN HaiXia;HOU LiJuan;WU MinJie;DONG FeiFei;Beijing Earthquake Agency;ARC Centre of Excellence from Core to Crust Fluid Systems,Department of Earth and Planetary Sciences, Macquarie University;Centre for Exploration Targeting,The University of Western Australia;Geological Survey of Western Australia;Geophysical Exploration Center,China Earthquake Administration;Guangdong Earthquake Agency;Institute of Geophysics,China Earthquake Administration;Jiangxi Earthquake Agency;
  • 关键词:Pb震相 ; 时频特征 ; 康拉德界面 ; 联合反演 ; 理论走时
  • 英文关键词:Pb phase;;Time-frequency characteristics;;Conrad interface;;Joint inversion;;Theoretical travel time
  • 中文刊名:DQWX
  • 英文刊名:Chinese Journal of Geophysics
  • 机构:北京市地震局;澳大利亚麦考瑞大学地球和行星科学系;澳大利亚西澳大学勘探预测中心;澳大利亚西澳地质调查局;中国地震局地球物理勘探中心;广东省地震局;中国地震局地球物理研究所;江西省地震局;
  • 出版日期:2019-07-15
  • 出版单位:地球物理学报
  • 年:2019
  • 期:v.62
  • 基金:国家自然科学基金(41474087,41604045);; 中国地震局地震科技星火计划青年项目(XH16004Y);; 国家留学基金管理委员会联合资助
  • 语种:中文;
  • 页:DQWX201907014
  • 页数:22
  • CN:07
  • ISSN:11-2074/P
  • 分类号:179-200
摘要
Pb震相是近震震相中的一个重要震相.关于Pb震相典型特征的总结和分析,对指导区域台网工作人员如何识别该震相,丰富台网观测报告震相产出,提高地震定位精度和确定康拉德界面等相关研究具有重要意义.但由于识别困难,国内很少有系统进行有关Pb震相的识别和研究工作.本研究采用首都圈地区高密度台网2009—2015年记录到的369个ML≥2.5地震事件的波形资料,重新分析震相并识别出1153条Pb震相.基于震相资料,利用时频分析、多项式拟合、射线分析、最小二乘法、联合反演、理论走时计算等方法进行研究,并在结合前人研究结果的基础上,我们得出:在首都圈及邻区,在肉眼可识别时频域内的特征来看,通常容易识别的Pb的振幅或频率高频部分相对比初至Pn和Pg大或高,也有振幅变小或者频率变化不明显的情况,这可能与震源机制、台站方位、场地响应、仪器类型等方面有关.时频分析、功率谱密度和肉眼识别分析的结果表明,P波的主要能量集中在相对低频部分,Pn,Pb,Pg,PmP四种震相(本研究以后提到的震相顺序只考虑这四种震相)有很强的共性,区别在于传播路径上的不同,频率或观测记录周期上的小幅度差别.在Pg作为初至波时,Pb震相的低频主频部分与Pg震相的低频主频部分带宽差不多(受到包含Pg震相的影响),但是高频主频部分频率更高,Pb到时在Pg之后,PmP之前.Pn作为初至波时,Pn震相低频主频部分带宽比Pb宽,但是Pb高频主频部分频率相对更高,Pb在Pn之后,在Pg之前.鉴于震源深度对Pb到时顺序的影响,及其在定位结果中精确度最差的情况,在震中距约在80~140km范围内时,得考虑区域地壳厚度横向不均匀、震中距、震源深度等情况并结合波形特征,来判定Pb是否为初至震相.Pb震相在康拉德界面的平均传播速度约为7.0km·s~(-1),康拉德界面平均深度约为23km.Pb射线的分布情况直接证明了康拉德界面在首都圈地区的分布是连续的.基于本研究利用Pg,Pb,Pn,PmP震相走时联合反演所得模型计算的理论走时结果和实际观测结果一致进一步证明了我们结果的可靠性.
        Seismic phase Pb is an important one in near events.Identifying this phase and summarizing its characteristics are important for enriching phase catalogs of regional networks,improving earthquake location accuracy and studying the Conrad interface.Due to many difficulties in identifying the phase,few studies have focused on this issue.This work employed waveform data from 369 ML≥2.5 local earthquakes between 2009 and 2015 recorded by the high density seismic network in the Capital Circle region around Beijing to identify 1153 Pb phases.We used a series of techniques to analyze these data,including time-frequency analysis,polynomial fitting,ray analysis,least square fitting,joint inversion,and theoretical travel time calculation and study the time-frequency features of the Pb phase and its propagating speed,and to infer the distribution of the Conrad interface.Combining with previous studies,the results show that in the study area,Pb arrivals that can be easily recognized generally have larger amplitudes and more high-frequency content than the first arrival Pn or Pg phases.There are also some cases in which the Pb phase has relatively weak amplitudes and no visible frequency changes,which can be attributed to differences in the focal mechanism,station azimuth,site response,and instrument type.Through time-frequency analysis,power spectral density and visual identification,we find that in the study area,the main energy of P-waves is concentrated in relatively low frequencies,including four main phases Pn,Pb,Pg and PmP(which are the only phases considered)share this common feature,with small variations due to different propagation paths.When Pg is the first arrival,the dominant low frequency content in the Pb phase is similar to that of the Pg phase(likely due to contamination of Pg phase),Pb,however,has relatively higher frequencies,and comes after Pg but before PmP.When Pn is the first arrival,its dominant low frequency content has broader bandwidth than the Pb,while Pb has higher frequencies and comes after Pn but before Pg.Given that the first appearance of Pb is highly influenced by source depth,and which has the least accuracy in source solutions,we suggest that for epicenter distances between 80 and 140 km,regional variations in the crust thickness,epicentral distance,source depth,and waveform characteristics must be combined to determine whether the Pb phase is the first arrival or not.The propagation speed of the Pb phase at the Conrad interface is about 7.0 km·s-1,and the average depth of the Conrad interface is about 23 km.The distribution of the Pb ray paths suggests a continuous distribution of the Conrad interface in the study area.The theoretical travel times,calculated using the velocity model determined in a joint travel time inversion of Pg,Pb,Pn,and PmP phases,agree well with the actual observations,suggesting that our results are robust.
引文
Bassin C,Laske G,Masters G.2000.The current limits of resolution for surface wave tomography in North America.Eos,Transactions American Geophysical Union,81:F897.
    Berry M J,Fuchs K.1973.Crustal structure of the superior and Grenville provinces of the Northeastern Canadian Shield.Bulletin of the Seismological Society of America,63(4):1393-1432.
    Bian G,Xia W,Jin S X,et al.2015.Datum reduction with the least squares fitting method in correction of multi-station geomagnetic diurnal variations.Chinese Journal of Geophysics(in Chinese),58(4):1284-1289,doi:10.6038/cjg20150416.
    Bormann P.2012.New Manual of Seismological Observatory Practice(NMSOP-2),IASPEI,GFZ German Research Centre for Geosciences,Potsdam.http:∥nmsop.gfz-potsdam.de.doi:10.2312/GFZ.NMSOP-2.
    China Earthquake Administration.2017.DB/T 66-2016Specification for Earthquake Cataloguing(in Chinese).Beijing:Seismological Press.
    Conrad V.1925.Laufzeitkurven des Tauernbebens vom 28.November,1923,Mitt.Erdb.Ko-mm.Wien.Akad.Wiss,59:1-23.
    Fan Y L,Lin J Z,Hu R H,et al.1990.The development of travel time table for near earthquake in south China.South China Seismological Journal(in Chinese),10(2):1-16.
    Fu S F,Liu B C.1991.Seismology Tutorial(in Chinese).Beijing:Seismological Press.
    Guo J,Zheng J,Wu J.2013.Analysis and discussion of local seismic unknown phase recorded by Puyang station.Journal of Henan Science and Technology(in Chinese),(1):28-29.
    Guo Y X,Huang Y,Zhang T Z,et al.2010.Primary research of natural earthquake phases in the north China region.Earthquake Research in China(in Chinese),26(1):112-122.
    He X,Hong T K.2010.Evidence for strong ground motion by waves refracted from the Conrad discontinuity.Bulletin of the Seismological Society of America,100(3):1370-1374.
    Heimann S,Kriegerowski M,Isken M,et al.2017.Pyrocko-An open-source seismology toolbox and library.V.0.3.GFZ Data Services.
    Jiao Y Y,Shen X Z,Li Q S.2017.Seismic evidence of the Conrad discontinuity on the northeast margin of the Tibetan Plateau and a tentative discussion on its tectonic implications.Acta Geoscientica Sinica(in Chinese),38(4):469-478.
    Kennett B L N.1993.IASPEI 1991Seismological Tables(in Chinese).Chen P S trans.Beijing:Seismological Press,166-167.
    Kerr R A.1989.Deep holes yielding geoscience surprises.Science,245(4917):468-470.
    Li S L,Zhang X L,Song Z L,et al.2001.Three-dimensional crustal structure of the capital area obtained by ajoint inversion of DSS data from multiple profiles.Chinese Journal of Geophysics(in Chinese),44(3):360-368.
    Li W,Liu Y K,Liu B J.2016.Downhole microseismic signal recognition and extraction based on sparse distribution features.Chinese Journal of Geophysics(in Chinese),59(10):3689-3882,doi:10.6038/cjg20161030.
    Lin X D,Ge H K,Xu P,et al.2013.Near field wave form inversion:Lushan magnitude 7.0earthquake and its aftershock moment tensor.Chinese Journal of Geophysics(in Chinese),56(12):4037-4047,doi:10.6038/cjg20131209.
    Lin X D,Yuan H Y,Xu P,et al.2017.Zonational characteristics of earthquake focal mechanism solutions in north China.Chinese Journal of Geophysics(in Chinese),60(12):4589-4622,doi:10.6038/cjg20171206.
    Lin X D,Dreger D,Ge H K,et al.2018.Spatial and temporal variations in the moment tensor solutions of the 2008Wenchuan Earthquake aftershocks and their tectonic implications.Tectonics,37(3):989-1005,doi:10.1002/2017TC004764.
    Litak R K,Brown L D.1989.A modern perspective on the Conrad discontinuity.Eos,Transactions American Geophysical Union,70(29):713-725.
    Pavlenkova N I.1993.The Kola superdeep drillhole and the nature of seismic boundaries.Terra Nova,4(1):117-123.
    Percival D B,Walden A T.1993.Spectral Analysis for Physical Applications:Multitaper and Conventional Univariate Techniques.Cambridge,UK:Cambridge University Press.
    Storchak D A,Schweitzer J,Bormann P.2003.The IASPEI standard seismic phase list.Seismological Research Letters,74(6):761-772.
    Sun W J,Kennett B L N.2016.Uppermost mantle P wave speed structure beneath eastern China and its surroundings.Tectonophysics,683:12-26.
    Sun W J,Kennett B L N.2017.Mid-lithosphere discontinuities beneath the western and central North China Craton.Geophysical Research Letters,44(3):1302-1310.
    Sun W J,Fu L Y,Wei W,et al.2018.The crust-mantle transition structures beneath eastern China.Chinese Journal of Geophysics(in Chinese),61(3):845-855,doi:10.6038/cjg2018L0551.
    Teng J W,Yao H,Zhou H N.1979.Crustal structure in the Beijing-Tianjin-Tangshan-Zhangjiakou region.Chinese Journal of Geophysics(Acta Geophysica Sinica)(in Chinese),22(3):218-236.
    Wan Y G,Li H J.1996.Genetic algorithms of the velocity structure and hypocenters simultaneous inversion in J.J.T.Z.Seismological and Geomagnetic Observation and Research(in Chinese),17(3):57-66.
    Wang L C,Zhu Y Q,Li X Y,et al.2016.Study on onedimensional crustal velocity model in Hebei area.North China Earthquake Sciences(in Chinese),34(4):1-10.
    Zhang H.2012.Primary analysis on earthquake Waveform characteristic of Taiyuan Basin.Earthquake Research in Shanxi(in Chinese),(2):1-4.
    Zhang S Q.1984.Introduction of seismic phases III.Seismological and Geomagnetic Observation and Research(in Chinese),42-48.
    Zhao Z H.1983.The joint determination of hypocenter parameters and velocity structure in the Beijing area of China.Chinese Journal of Geophysics(Acta Geophysica Sinica)(in Chinese),26(2):131-139.
    Zheng T Y,Duan Y H,Xu W W,et al.2015.Crust and upper mantle velocity model of North China v2.0.http:∥www.craton.cn/data.
    Zheng X F,Zhang H Z,Sun J H,et al.1999.Beijing Telemetered Seismograph Network DAPS System and Its Data Application Manual.Institute of Geophysics,China Earthquake Administration,No.99FC3007.
    Zhu Z P,Zhang X K,Zhang J S,et al.1997.Crust and upper mantle tectonic and velocity structure study on Beijing-HuailaiFengzheng reflection profile.Acta Seismologica Sinica(in Chinese),19(5):499-505.
    边刚,夏伟,金绍华等.2015.利用最小二乘拟合法进行多站地磁日变基值归算.地球物理学报,58(4):1284-1289,doi:10.6038/cjg20150416.
    范玉兰,林继增,胡瑞贺等.1990.华南地区近震走时表的研制.华南地震,10(2):1-16.
    傅淑芳,刘宝诚.1991.地震学教程.地震出版社.
    郭杰,郑杰,吴静.2013.濮阳台地方震不明震相分析探讨.河南科技,(1):28-29.
    郭永霞,黄媛,张天中等.2010.华北地区天然地震震相特征研究.中国地震,26(1):112-122.
    焦煜媛,沈旭章,李秋生.2017.青藏高原东北缘康拉德界面存在的地震学证据及构造意义初探.地球学报,38(4):469-478.
    Kennett B L N.1993.IASPEI 1991地震走时表.陈培善译.北京:地震出版社,166-167.
    李松林,张先康,宋占隆等.2001.多条人工地震测深剖面资料联合反演首都圈三维地壳结构.地球物理学报,44(3):360-368.
    李稳,刘伊克,刘保金.2016.基于稀疏分布特征的井下微地震信号识别与提取方法.地球物理学报,59(10):3869-3882,doi:10.6038/cjg20161030.
    林向东,葛洪魁,徐平等.2013.近场全波形反演:芦山7.0级地震及余震矩张量解.地球物理学报,56(12):4037-4047,doi:10.6038/cjg20131209.
    林向东,袁怀玉,徐平等.2017.华北地区地震震源机制分区特征.地球物理学报,60(12):4589-4622,doi:10.6038/cjg20171206.
    孙伟家,符力耘,魏伟等.2018.中国东部地区的壳-幔过渡带结构.地球物理学报,61(3):845-855,doi:10.6038/cjg2018L0551.
    滕吉文,姚虹,周海南.1979.北京、天津、唐山和张家口地区的地壳结构.地球物理学报,22(3):218-236.
    万永革,李鸿吉.1996.京津唐张地区速度结构和震源位置联合反演的遗传算法.地震地磁观测与研究,17(3):57-66.
    王莉婵,朱元清,李雪英等.2016.河北地区地壳一维速度模型的新近研究.华北地震科学,34(4):1-10.
    张惠.2012.浅析太原盆地地震波形特征.山西地震,(2):1-4.
    张少泉.1984.震相概述第三讲.地震地磁观测与研究,42-48.
    赵仲和.1983.北京地区地震参数与速度结构的联合测定.地球物理学报,26(2):131-139.
    郑天愉,段永红,许卫卫等.2015.华北地区地壳-上地幔地震波速度结构模型v2.0.(2017-02).http://www.craton.cn/data.
    郑秀芬,张宏志,孙静华等.1999.北京遥测地震台网DAPS系统及其数据应用手册.中国地震局地球物理研究所科研论著编号99FC3007.
    中国地震局.2017.DB/T 66-2016地震编目规范.北京:地震出版社.
    祝治平,张先康,张建狮等.1997.北京-怀来-丰镇剖面地壳上地幔构造与速度结构研究.地震学报,19(5):499-505.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700