广西龙滩库区深部孕震结构大地电磁探测研究
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
在广西龙滩库区布置2条北北西-南东东向大地电磁探测剖面进行了32个测点的观测,观测频段为320Hz~1000s.对2条剖面上测量和计算得到的各种电磁参数、深部电性结构图像以及库区地质构造、岩性和水域分布等进行分析研究.结果显示库区发育的6条断裂在电性上表现为不同程度的电性差异边界,其中拉浪—达良断裂和拉色—辉马断裂为库区主要断裂带.库区深部电性结构总体表现为纵向上自地表到20km深度呈现高—低—高的波浪起伏的三层结构,横向上呈明显的高低电阻块状组合样式.龙滩库区4个地震丛集区的震源都位于高、低电阻接触带附近,其中3个地震丛集区的震源位于低阻特性的石炭系地层的下部,为岩溶水体诱发地震;发生最大震级的地震丛集区的震源位于上宽下窄似"铆钉状"的高阻体下部,推测是因水库蓄水后水体压力增大和库水渗透作用下在聚集高变形能的脆性高电阻体内部发生的地震.
A magnetotelluric(MT) survey was carried out at 32 sites along two NNW-SEE trending profiles across the Longtan reservoir in Guangxi Province,with a measurement frequency band 320 Hz~1000 s.From the acquired MT data,electromagnetic parameters and images of deep electric structure beneath the study area were obtained,allowing us to conduct an integrated analysis of the seismotectonics in combination with geological structure,lithology and water system distribution of this region.The result indicates that there are 6 faults in the reservoir area,which can be identified by difference of electric property,among which the Lalang-Daliang and Lase-Huima faults are the primary fractures.The electric structure below the reservoir can be described by a three-layer model which is characterized by high-low-high values from the surface to depth 20m in vertical direction.In horizontal direction,the structure exhibits a pattern of combined blocks with high and low resistivity values.The sources of 4 earthquake clustering areas all lie nearby the boundary between high and low resistivity zones,of which the 3 sources are located in the lower portion of the Carboniferous stratum with low resistivity,attributed to induced events associated with water in karsts.The seismic event with the maximum magnitude occurred within the lower high-resistivity body,of which the width tapers downward.It is speculated that the earthquakes in this reservoir can be attributed to strain accumulation in the high-resistivity body due to the increase of water pressure after water storage and the water permeation.
引文
[1]Chander R.Can dams and reservoirs cause earthquakes?Triggering of Earthquakes.Resonance,1999,11:1-10.
    [2]Gupta H K.A review of recent studies of triggered earthquakesby artificial water reservoirs with special emphasis on earthquakesin Koyna,India.Earth Science Reviews,2002,58(3-4):279-310.
    [3]Chen L Y,Talwan P.Reservoir-induced seismicity in China.Pure Aappl.Geophys.,1998,153(1):133-149.
    [4]Simpson D W,Negmatullaev S K.Induced seismicity atNurek reservoir,Tadjikistan,USSR.Bulletin of theSeismological Society of America,1981,71(5):1561-1586.
    [5]胡毓良.诱发地震.国际地震动态,1996,(6):37-38.Hu Y L.The reservoir induced earthquakes.Recent Developmentsin Word Seismology(in Chinese),1996,(6):37-38.
    [6]易立新,车用太,王广才.水库诱发地震研究的历史、现状与发展趋势.华南地震,2003,23(1):28-37.Yi L X,Che Y T,Wang G C.Retrospection and prospect ofthe research on reservoir induced seismicity.South ChinaEarthquake of Seismology(in Chinese),2003,23(1):28-37.
    [7]Rajendran K.Sensitivity of a seismically active reservoir tolow-amplitude fluctuations:Observations from Lake Jocassee,South Carolina.Pure Appl.Geophys.,1995,145(1):87-95.
    [8]Hu P,Hu Y L.Advances in reservoir-induced seismicityresearch in China.Tectonophysics,1992,209(1-4):331-337.
    [9]Hu Y L,Liu Z Y,Yang Q Y,et al.Induced seismicity atWujiangdu reservoir,China:A case induced in the karstarea.Pure Appl.Geophys.,1996,147(2):400-418.
    [10]Leith W,Simpson D W,Alvarez W.Structure andpermeability:Geologic controls on induced seismicity atNurek reservoir,Tadjikistan,USSR.Geology,1981,9(10):440-444.
    [11]Talwani P.On the nature of reservoir-induced seismicity.Pure Appl.Geophys.,1997,150:473-492.
    [12]杨主恩,林传勇,高振寰等.东江水库诱发地震的地震地质背景研究.地震地质,1995,17(3):241-252.Yang Z E,Ling C Y,Gao Z H,et al.Studies onseismogeological background for Dongjiang reservokr-inducedearthquake.Seismology and Geology(in Chinese),1995,17(3):241-252.
    [13]林松建,黄昭,连玉平等.水口水库诱发地震特征与发震断裂的探讨.大地测量与地球动力学,2007,27(1):40-44.Lin S J,Huang Z,Lian Y P,et al.On characteristics andseismogenic faults of induced earthquake of ShuiKou reservoirin Fujian Province.Journal of Geodesy and Geodynamics(inChinese),2007,27(1):40-44.
    [14]陈蜀俊,姚运生,曾佐勋.三峡水库蓄水对库区孕震环境及潜在震源影响研究.大地测量与地球动力学,2005,25(3):116-120.Chen S J,Yao Y S,Zeng Z X.Effect of impounding onseismogenic environment and potential focus in head region ofThree Gorge Reservoir.Journal of Deformation andEarthquake(in Chinese),2005,25(3):116-120.
    [15]雷兴林,马胜利,闻学泽等.地表水体对断层应力与地震时空分布影响的综合分析—以紫坪铺水库为例.地震地质,2008,30(4):1046-1064.Lei X L,Ma S L,Wen X Z,et al.Integrated analysis ofstress and regional seismicity by surface loading—A casestudy of Zipingpu reservoir.Seismology and Geology(inChinese),2008,30(4):1046-1064.
    [16]Talwani P.Seismogenic properties of the crust inferred fromrecent studies of reservoir-induced seismicity-application toKoyna.Current Science,2000,79(9):1327-1333.
    [17]史水平,于学庆,龙政强等.龙滩库区蓄水后地震性质分析.地震地磁观测与研究,2010,31(3):40-45.Shi S P,Yu X Q,Long Z Q,et al.Analysis on the nature ofearthquake in Longtan area after the reservoir storage water.Seismological and Geomagnetic Observation and Research(inChinese),2010,31(3):40-45.
    [18]姚宏,杨松文,陈斌.Canopy宽带接入系统在龙滩水电工程数字遥测地震台网信道优化设计中的应用.地震地磁观测与研究,2007,28(6):63-68.Yao H,Yang S W,Chen B.The application of Canopywireless broadband access for channel optimize design inLongtan digital telemetry seismograph Network.Seismologicaland Geomagnetic Observation and Research(in Chinese),2007,28(6):63-68.
    [19]陈翰林,赵翠萍,修济刚等.龙滩水库地震精定位及活动特征研究.地球物理学报,2009,52(8):2035-2043.Chen H L,Zhao C P,Xiu J G,et al.Study on preciserelocation of Longtan reservoir earthquakes and its seismicactivity.Chinese J.Geophys.(in Chinese),2009,52(8):2035-2043.
    [20]陈翰林,赵翠萍,修济刚等.龙滩库区水库地震震源机制及应力场特征.地震地质,2009,31(4):686-698.Chen H L,Zhao C P,Xiu J G,et al.Study on thecharacteristics of focal mechanisms of reservoir inducedearthquakes and stress field in the Longtan reservoir area.Seismology and Geology(in Chinese),2009,31(4):686-698.
    [21]陈乐寿,王光锷.大地电磁测深法.北京:地质出版社,1990.Chen L S,Wang G E.Method of Magetotelluric Sounding(in Chinese).Beijing:Geological Publishing House,1990.
    [22]徐常芳.壳内流体演化及地震成因(三).地震学报,1997,19(2):139-144.Xu C F.The crustal fluid evolution and the causes ofearthquakes(3).Acta Seismologica Sinica(in Chinese),1997,19(2):139-144.
    [23]赵国泽,刘国栋,詹艳等.张北—尚义地震区及其邻区地壳上地幔结构.地震地质,1998,20(2):155-162.Zhao G Z,Liu G D,Zhan Y,et al.The structure of thecrust and upper mantle for the Zhangbei-Shangyi seismic areaand its neighbouring region.Seismology and Geology(inChinese),1998,20(2):155-162.
    [24]詹艳,赵国泽,汤吉等.新疆玛纳斯大震区地壳深部的电性结构.地震地质,1999,21(2):159-167.Zhan Y,Zhao G Z,Tang J,et al.Electric structure of thecrust of the Manas earthquake area in Xinjiang autonomousregion.Seismology and Geology(in Chinese),1999,21(2):159-167.
    [25]詹艳,赵国泽,王继军等.1927年古浪8级大震区及其周边地块的深部电性结构.地球物理学报,2008,51(2):220-229.Zhan Y,Zhao G Z,Wang J J,et al.Deep electric structurebeneath the epicentre of the 1927Gulang M8earthquake andits adjacent areas from magnetotelluric sounding.Chinese J.Geophysics(in Chinese),2008,51(2):220-229.
    [26]詹艳,赵国泽,陈小斌等.宁夏海原大震区西安州—韦州剖面大地电磁探测与研究.地球物理学报,2004,47(2):274-281.Zhan Y,Zhao G Z,Chen X B,et al.Crustal structure frommagnetotelluric profiling in the Haiyuan earthquake area,Ningxia Hui Autonomous region,China.Chinese J.Geophys.(in Chinese),2004,47(2):305-313.
    [27]Chen C C,Chen C S,Shieh C F.Crustal electricalconductors,crustal fluids and 1999 Chi-Chi,Taiwan,earthquake.TAO,2002,13(3):367-374.
    [28]Ogawa Y,Mishina M,Goto T,et al.Magnetotelluricimaging of fluids in intraplate earthquake zones,NE Japanback arc.Geophys.Res.Lett.,2001,28(19):3741-3744.
    [29]Unsworth M,Bedrosian P A.On the geoelectric structure ofmajor strike-slip faults and shear zones.Earth PlanetsSpace,2004,56:1177-1184.
    [30]Goto T N,Wada Y,Oshiman N,et al.Resistivity structureof a seismic gap along the Atotsugawa Fault,Japan.Physicsof the Earth and Planetary Interiors,2005,148(1):55-72.
    [31]Tank S B,Honkura Y,Ogawa Y,et al.Resistivity structurein the western part of the fault rupture zone associated withthe 1999Izmit earthquake and its seismogenic implication.Earth Planets Space,2003,55:437-442.
    [32]Ingham M,Whaler K,Mcknight D.Magnetotelluricsounding of the Hikurangi Margin,New Zealand.Geophy.J.Ini.,2001,144(2):343-355.
    [33]Ingham M.High resolution electrical imaging of fault zones.Physics of the Earth and Planetary Interiors,2005,150(1-3):93-105.
    [34]Wannamaker P E,Grant Caldwell T,Doerner W M,et al.Fault zone fluids and seismicity in compressional andextensional environments inferred from electrical conductivity:theNew Zealand Southern Alps and U.S.Great Basin.EarthPlanets Space,2004,56:1171-1176.
    [35]广西壮族自治区地质局.南丹幅地质图.北京:地质出版社,1968.Guangxi Bureau of Geology.Nandan Geological Map(inChinese).Beijing:Geological Publishing House,1968.
    [36]徐宗学,黄乃安,常宝琦.广西龙滩水库诱发地震环境影响评价.华南地震,1989,9(2):84-91.Xu Z X,Huang N A,Chang B Q.The evaluation of GuangxiLongtan reservoir induced earthquake environmental impact.South China Journal of Seismology(in Chinese),1989,9(2):84-91.
    [37]郭培兰,姚宏,袁媛.龙滩水库地震危险性分析.高原地震,2006,18(4):17-23.Guo P L,Yao H,Yuan Y.Analysis on potential seismic riskin Longtan Reservoir.Plateau Earthquake Research(inChinese),2006,18(4):17-23.
    [38]Egbert G D,Booker J R.Robust estimation of geomagnetictransfer functions.Geophysical Journal of the Royal AstronomicalSociety,1986,87(1):173-194.
    [39]Chave A D,Thomson D J,Ander M E.On the robustestimation of power spectra,coherences,and transfer functions.J.Geophys.Res.,1987,92(B1):633-648.
    [40]陈小斌,赵国泽,詹艳.MT资料处理与解释的Windows可视化集成系统.石油地球物理勘探,2004,39(增):11-16.Chen X B,Zhao G Z,Zhan Y.A visual intergrated windowssystem for MT data process and interpretation.Oil GeophysicalProspecting(in Chinese),2004,39(Suppl.):11-16.
    [41]Caldwel T G,Bibby M H,Brown C.The magnetotelluricphase tensor.Geophysical Journal International,2004,158(2):457-469.
    [42]蔡军涛,陈小斌,赵国泽.大地电磁资料精细处理和二维反演解释技术研究(一)——阻抗张量分解与构造维性分析.地球物理学报,2010,53(10):2516-2526.Cai J T,Chen X B,Zhao G Z.Refined techniques for dataprocessing and two-dimensional inversion in magnetotelluricⅠ:Tensor decomposition and dimensionality analysis.Chinese J.Geophysics(in Chinese),2010,53(10):2516-2526.
    [43]肖骑彬.基于数据库平台的MT数据处理可视化方案.物探与化探,2005,29(3):269-272.Xiao Q B.A visualization scheme of MT data processingbased on database platform.Geophysical and GeochemicalExploration(in Chinese),2005,29(3):269-272.
    [44]Rodi W,Mackie R L.Nonlinear conjugate gradients algorithmfor 2-D magnetotelluric inversion.Geophysics,2001,66(1):174-187.
    [45]易立新,王广才,李榴芬.水文地质结构与水库诱发地震.水文地质工程地质,2004,31(2):29-32.Yi L X,Wang G C,Li L F.Hydrogeological structure andreservoir induced seismicity.Hydrogeology and EngineeringGeology(in Chinese),2004,31(2):29-32.
    [46]易立新,车用太.水库诱发地震及其水文地质条件和诱震机理.中国地质灾害与防治学报,2006,11(2):46-50.Yi L X,Che Y T.The mechanism of reservoir-inducedearthquake related to hydrogeological condition.The ChineseJournal of Geological Hazard and Control(in Chinese),2006,11(2):46-50.

版权所有:© 2023 中国地质图书馆 中国地质调查局地学文献中心