利用三维高斯射线束成像进行地震定位
详细信息 本馆镜像全文    |  推荐本文 | | 获取馆网全文
摘要
常规的地震定位方法通常需要拾取地震记录的初至,当初至不明显或被较高水平的噪声淹没时精度较低.本文采用基于三维高斯射线束的偏移成像方法对震源进行定位,较好地解决了该问题.通过三维高斯射线束对台站记录进行偏移归位,并将各台站成像结果的交点作为地震能量释放的中心位置;当各台站成像结果不能交于一点时,采用三维空间高斯滤波方法可实现震源位置的自动获取.提出的变网格计算方案极大地减少了计算量,显著地提高了成像精度和计算效率.利用首都圈地震台网数据,对涿鹿、滦县以及房山三个地震事件进行试算,结果表明:基于变网格三维高斯束偏移成像的地震定位方法自动化程度很高,而且具有较好的抗噪能力,特别适合处理低信噪比资料的地震定位问题.
Traditional earthquake location methods usually need to pick first arrivals of signals,which have a low precision when these arrivals are unremarkable or submerged by strong noise.In this paper,we employ the 3-D varying-grid Gaussian beam migration imaging method to determine seismic source locations.We apply this method to deal with the synthetic seismograms and real seismic events in the Capital Circle region around Beijing to verify the validity of this method.We migrate every record of the station backward and take the position where all the imaging results merge relatively as the source location that releases the dominant energy.We propose to use the numerical scheme of varying grid.Firstly we utilize the method of global search to obtain the quick result of the epicenter in the coarse grid condition,and then we determine the final source location just by the local search within the epicenter area with a fine grid.We also employ a 3-D spatial Gaussian filter to obtain the source location and suppress the background noise automatically when the imaging results are scattered or unfocused,getting rid of searching for the major spatial energy points in the conventional least square method.The results based on the synthetic data show that the method combining the varying-grid 3-D Gaussian beam and spatial Gaussian filter can not only ensure the high efficiency with less steps of ray tracing but also can be more adaptable to the low signal-to-noise ratio data and scattered or unfocused imaging energy.Besides,we also test the proposed method on the data of Zhuolu,Luanxian and Fangshan earthquakes in the Capital Circle region around Beijing,which can further confirm the efficiency and accuracy of the method.The earthquake location method based on 3-D varying-grid Gaussian beam migration imaging just needs the rough picking of first arrivals,which is more robust to the pickup error than conventional methods. The method implements the unification of imaging accuracy and computational efficiency,and is highly automatic and suitable for noisy data especially in low signal-to-noise ratio cases.
引文
Baker T,Granat R,Clayton R W.2005.Real-time earthquakelocation using Kirchhoff reconstruction.Bull.Seism.Soc.Am.,95(2):699-707.
    Cai M J,Shan X M,Xu Y,et al.2004.Review of earthquakelocating methods from error.Journal of SeismologicalResearch(in Chinese),27(4):314-317.
    Cerveny′V,Popov M M,Psencík L.1982.Computation of wavefields in inhomogeneous media:Gaussian beam approach.Geophys.J.R.Astr.Soc.,70(1):109-128.
    Cerveny′V,Pˇsencík L.1984.Gaussian beams in elastic 2-D laterallyvarying layered structures.Geophys.J.R.Astr.Soc.,78(1):65-91.
    Cerveny′V.1985.Gaussian beam synthetic seismograms.J.Geophys.,58:44-72.
    Cerveny′V.2001.Seismic Ray Theory.Cambridge:CambridgeUniversity Press.
    Fitch T J.1975.Compressional velocity in source regions of deepearthquakes:an application of the master earthquaketechnique.Earth Planet.Sci.Lett.,26(2):156-166.
    Flinn E A.1965.Confidence regions and error determinations forseismic event location.Rev.Geophys.,3(1):157-185.
    Fukao Y.1972.Source process of a large deep-focus earthquake andits tectonic implications—the western Brazil earthquake of1963.Physics of the Earth and Planetary Interior,5:61-76.
    Gao X,Wang W M,Yao Z X.2002.Hypocentral determinationusing simulated annealing method.Chinese J.Geophys.(inChinese),45(4):525-532.
    Geiger L.1912.Probability method for the determination ofearthquake epicenters from arrival time only.Bull.St.Louis.Univ.,8:60-71.
    Hale D.1992.Migration by the Kirchhoff,slant stack and Gaussianbeam methods.Colorado School of Mines Center for WavePhenomena Report,121.
    Hill N R.1990.Gaussian beam migration.Geophysics,55(11):1416-1428.
    Hill N R.2001.Prestack Gaussian-beam depth migration.Geophysics,66(4):1240-1250.
    Huang Y,Li Q H,Zhang Y S,et al.2008.Relocation ofearthquakes in Jiangsu and neighboring areas,China andanalysis of structural features.Chinese J.Geophys.(inChinese),51(1):175-185.
    Kao H,Shan S J.2004.The source-scanning algorithm:Mappingthe distribution of seismic sources in time and space.Geophys.J.Int.,157(2):589-594.
    Kao H,Shan S J.2007.Rapid identification of earthquake ruptureplane using Source-Scanning Algorithm.Geophys.J.Int.,168(3):1011-1020.
    Lay T,Wallace T C.1995.Modern Global Seismology.New York:Academic Press Inc..
    Li Z C,Yue Y B,Guo C B,et al.2010.Gaussian beam commonangle preserved-amplitude migration.Oil Geophysical Prospecting(in Chinese),45(3):360-365.
    Lian C,Li S L,Dong M,et al.2006.Method of spherical surfaceshearing in earthquake location.Journal of Geodesy andGeodynamics(in Chinese),26(2):99-103.
    McMechan G A.1982.Determination of source parameters bywavefield extrapolation.Geophys.J.R.Astr.Soc.,71(3):613-628.
    McMechan G A,Luetgert J H,Mooney W D.1985.Imaging ofearthquake sources in Long Valley Caldera,California,1983.Bull.Seism.Soc.Am.,75(4):1005-1020.
    Oppenheim A V,Schafer R W,Buck J R.1999.Discrete-TimeSignal Processing.2nd ed.Upper Saddle River,NJ:Prentice-Hall.
    Popov M M.1982.A new method of computation of wave fieldsusing Gaussian beams.Wave Motion,4(1):85-97.
    Rentsch S,Buske S,Luth S,et al.2007.Fast location ofseismicity:A migration-type approach with application tohydraulic-fracturing data.Geophysics,72(1):S33-S40.
    Shearer P M.1997.Improving local earthquake locations using theL1norm and waveform cross correlation:Application to theWhittier Narrows,California,aftershock sequence.J.Geophys.Res.:Solid Earth,102(B4):8269-8283.
    Tian Y,Chen X F.2002.Review of seismic location study.Progress in Geophysics(in Chinese),17(1):147-155,doi:10.3969/j.issn.1004-2903.2002.01.022.
    Tian Y,Chen X F.2006.Simultaneous inversion of hypocenters andvelocity using the quasi-Newton method and trust regionmethod.Chinese J.Geophys.(in Chinese),49(3):845-854.
    Waldhauser F,Ellsworth W L.2000.A double-difference earthquakelocation algorithm:method and application to the northern Haywardfault,California.Bull.Seism.Soc.Am.,90(6):1353-1368.
    Xu L S,Du H L,Yan C,et al.2013.A method for determinationof earthquake hypocentroid:time-reversal imaging techniqueⅠ—Priniple and numerical tests.Chinese J.Geophys.(inChinese),56(4):1190-1206,doi:10.6038/cjg20130414.
    Yang Z X,Chen Y T,Zheng Y J,et al.2003.Accurate relocationof earthquakes in central-western China using double differenceearthquake location algorithm.Science in China Series D:Earth Sciences,46(S2):181-188.
    Yao Z X,Harkider D G.1983.A generalized reflection-transmissioncoefficient matrix and discrete wavenumber method for syntheticseismograms.Bull.Seism.Soc.Am.,73(6A):1685-1699.
    Yao Z X,Wang C Y,Lou H.2010.Ascertaining the structureparameters of Kunlun fault zone using the grid searchingmethod based on trapped wave correlation.Chinese J.Geophys.(in Chinese),53(5):1167-1172,doi:10.3969/j.issn.0001-5733.2010.05.018.
    Yue Y B,Li Z C,Zhang P,et al.2010.Prestack Gaussian beamdepth migration under complex surface conditions.AppliedGeophysics,7(2):143-148.
    Yue Y B,Li Z C,Qian Z P,et al.2012.Amplitude-preservedGaussian beam migration under complex topographic conditions.Chinese J.Geophys.(in Chinese),55(4):1376-1383,doi:10.6038/j.issn.0001-5733.2012.04.033.
    Zhou J C,Zhao A H.2012.An intersection method for locatingearthquakes in 3-D complex velocity models.Chinese J.Geophys.(in Chinese),55(10):3347-3354,doi:10.6038/j.issn.0001-5733.2012.10.017.
    蔡明军,山秀明,徐彦等.2004.从误差观点综述分析地震定位方法.地震研究,27(4):314-317.
    高星,王卫民,姚振兴.2002.用于地震定位的SAMS方法.地球物理学报,45(4):525-532.
    黄耘,李清河,张元生等.2008.江苏及临区地震重新定位和构造特征分析.地球物理学报,51(1):175-185.
    李振春,岳玉波,郭朝斌等.2010.高斯波束共角度保幅深度偏移.石油地球物理勘探,45(3):360-365.
    廉超,李胜乐,董曼等.2006.球面交切法地震定位.大地测量与地球动力学,26(2):99-103.
    田玥,陈晓非.2002.地震定位研究综述.地球物理学进展,17(1):147-155,doi:10.3969/j.issn.1004-2903.2002.01.022.
    田玥,陈晓非.2006.利用拟牛顿法和信赖域法联合反演震中分布与一维速度结构.地球物理学报,49(3):845-854.
    许力生,杜海林,严川等.2013.一种确定震源中心的方法:逆时成像技术(一)———原理与数值实验.地球物理学报,56(4):1190-1206,doi:10.6038/cjg20130414.
    杨智娴,陈运泰,郑月军等.2003.双差地震定位法在我国中西部地区地震精确定位中的应用.中国科学D辑:地球科学,33(增刊):129-134.
    姚志祥,王椿镛,楼海.2010.利用基于围陷波波形相关的网格搜索法确定昆仑山断裂带结构参数.地球物理学报,53(5):1167-1172,doi:10.3969/j.issn.0001-5733.2010.05.018.
    岳玉波,李振春,钱忠平等.2012.复杂地表条件下保幅高斯束偏移.地球物理学报,55(4):1376-1383,doi:10.6038/j.issn.0001-5733.2012.04.033.
    周建超,赵爱华.2012.三维复杂速度模型的交切法地震定位.地球物理学报,55(10):3347-3354,doi:10.6038/j.issn.0001-5733.2012.10.017.

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