北京地震前的异常次声波
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摘要
观测并研究了2011年10月12日发生在北京海淀区的一次小地震前4天,五个次声监测站点接收到的异常次声波信号.这五路信号的波形一致,均为"N"形脉冲波,且持续时间基本一致,约在一个小时左右.基于Wigner-Ville分布方法对信号进行时频分析发现次声波能量主要集中在0.025Hz的频率以下.五路信号间的相关系数均高达0.8左右.采用波束形成方法对信号源进行成像定位研究,其结果表明:该地震前异常次声波源的位置与地震发生时震中的位置相差约5km.本文的分析结果说明了地震前可能有低频大气次声波的产生,研究这类次声波可能为地震的预测提供一种有价值的信息.
Anomalous infrasound waves were received by five infrasonic monitoring stations four days before a small-magnitude earthquake which happened on 12 October 2011.Waveforms of these five signals are consistent,which are "N" impulse waves with same duration of about one hour.Based on the Wigner-Ville distribution method,time-frequency analysis of the signals suggests that waves′ energies concentrate mainly below the frequency of 0.025 Hz.Correlation coefficients between two signals are all up to about 0.8.The infrasonic source is imaged and located by the method of beamforming,and the results show that distance between the source and epicenter is about 5 km.Study of this paper proves that low-frequency atmospheric infrasonic waves may appear before earthquakes,so valuable information could be obtained by studying this kind of infrasonic waves.
Anomalous infrasound waves were received by five infrasonic monitoring stations four days before a small-magnitude earthquake which happened on 12 October 2011.Waveforms of these five signals are consistent,which are "N" impulse waves with same duration of about one hour.Based on the Wigner-Ville distribution method,time-frequency analysis of the signals suggests that waves′ energies concentrate mainly below the frequency of 0.025 Hz.Correlation coefficients between two signals are all up to about 0.8.The infrasonic source is imaged and located by the method of beamforming,and the results show that distance between the source and epicenter is about 5 km.Study of this paper proves that low-frequency atmospheric infrasonic waves may appear before earthquakes,so valuable information could be obtained by studying this kind of infrasonic waves.
引文
[1]Le Pichon A,Blanc E,Hauchecorne A.InfrasoundMonitoring for Atmospheric Studies.New York:Springer,2010.
[2]Evers L G.The inaudible symphony:on the detection andsource identification of atmospheric infrasound[Ph.D.thesis].Netherlands:Delft University of Technology,2008.
[3]Garcés M A,Hansen R A.Waveform analysis ofseismoacoustic signals radiated during the fall 1996eruptionof Pavlof volcano,Alaska.Geophys.Res.Lett.,1998,25(7):1051-1054.
[4]Garcés M A,Iguchi M,Ishihara K,et al.Infrasonicprecursors to a vulcanian eruption at Sakurajima volcano,Japan.Geophys.Res.Lett.,1999,26(16):2537-2540.
[5]Assink J D,Evers L G,Holleman I,et al.Characterizationof infrasound from lightning.Geophys.Res.Lett.,2008,35(15):L15802,doi:10.1029/2008GL034193.
[6]Bolt B A.Seismic air waves from the great 1964 Alaskanearthquake.Nature,1964,202(4937):1095-1096.
[7]Mutschlecner J P,Whitaker R W.Infrasound fromearthquakes.J.Geophys.Res.,2005,110:D0108,doi:10.1029/2004JD005067.
[8]Mikumo T,Shibutani T,Le Pichon A,et al.Low-frequencyacoustic-gravity waves from coseismic vertical deformationassociated with the 2004 Sumatra-Andaman earthquake(Mw=9.2).J.Geophys.Res.,2008,113:B12402,doi:10.1029/2008JB005710.
[9]Le Pichon A,Herry P,Mialle P,et al.Infrasound associatedwith 2004—2005large Sumatra earthquakes and tsunami.Geophys.Res.Lett.,2005,32(19):L19802,doi:10.1029/2005GL023893.
[10]Cansi Y.An automatic seismic event processing for detectionand location:The P.M.C.C.method.Geophys.Res.Lett.,1995,22(9):1021-1024.
[11]Havelock D,Kuwano S,Vorlander M.Handbook of SignalProcessing in Acoustics(Vol.1).New York:Springer,2008.
[12]Cansi Y,Klinger Y.An automated data processing methodfor mini-arrays.Newsletter of the European-MediterraneanSeismological Centre,1997,11:2-4.
[13]Smart E,Flinn E A.Fast frequency-wavenumber analysisand Fisher signal detection in real-time infrasonic array dataprocessing.Geophys.J.Roy.Astr.Soc.,1971,26(1-4):279-284.
[14]林琳,杨亦春.大气中一种低频次声波观测研究.声学学报,2010,35(2):200-207.Lin L,Yang Y C.Observation&study of a kind of low-frequency atmospheric infrasonic waves.Acta Acustica(inChinese),2010,35(2):200-207.
[15]胡心康,石金瑞,任建国.大气中一种压力波动与地震关系的初步探索.地球物理学报,1980,23(4):450-458.Hu X K,Shi J R,Ren J G.Preliminary study of the relationbetween a kind of pressure waves in the atmosphere andearthquakes.Chinese J.Geophys.(in Chinese),1980,23(4):450-458.
[16]张贤达,保铮.非平稳信号分析与处理.北京:国防工业出版社,1998.Zhang X D,Bao Z.Non-stationary Signal Analysis andProcessing(in Chinese).Beijing:National Defence IndustryPress,1998.
[2]Evers L G.The inaudible symphony:on the detection andsource identification of atmospheric infrasound[Ph.D.thesis].Netherlands:Delft University of Technology,2008.
[3]Garcés M A,Hansen R A.Waveform analysis ofseismoacoustic signals radiated during the fall 1996eruptionof Pavlof volcano,Alaska.Geophys.Res.Lett.,1998,25(7):1051-1054.
[4]Garcés M A,Iguchi M,Ishihara K,et al.Infrasonicprecursors to a vulcanian eruption at Sakurajima volcano,Japan.Geophys.Res.Lett.,1999,26(16):2537-2540.
[5]Assink J D,Evers L G,Holleman I,et al.Characterizationof infrasound from lightning.Geophys.Res.Lett.,2008,35(15):L15802,doi:10.1029/2008GL034193.
[6]Bolt B A.Seismic air waves from the great 1964 Alaskanearthquake.Nature,1964,202(4937):1095-1096.
[7]Mutschlecner J P,Whitaker R W.Infrasound fromearthquakes.J.Geophys.Res.,2005,110:D0108,doi:10.1029/2004JD005067.
[8]Mikumo T,Shibutani T,Le Pichon A,et al.Low-frequencyacoustic-gravity waves from coseismic vertical deformationassociated with the 2004 Sumatra-Andaman earthquake(Mw=9.2).J.Geophys.Res.,2008,113:B12402,doi:10.1029/2008JB005710.
[9]Le Pichon A,Herry P,Mialle P,et al.Infrasound associatedwith 2004—2005large Sumatra earthquakes and tsunami.Geophys.Res.Lett.,2005,32(19):L19802,doi:10.1029/2005GL023893.
[10]Cansi Y.An automatic seismic event processing for detectionand location:The P.M.C.C.method.Geophys.Res.Lett.,1995,22(9):1021-1024.
[11]Havelock D,Kuwano S,Vorlander M.Handbook of SignalProcessing in Acoustics(Vol.1).New York:Springer,2008.
[12]Cansi Y,Klinger Y.An automated data processing methodfor mini-arrays.Newsletter of the European-MediterraneanSeismological Centre,1997,11:2-4.
[13]Smart E,Flinn E A.Fast frequency-wavenumber analysisand Fisher signal detection in real-time infrasonic array dataprocessing.Geophys.J.Roy.Astr.Soc.,1971,26(1-4):279-284.
[14]林琳,杨亦春.大气中一种低频次声波观测研究.声学学报,2010,35(2):200-207.Lin L,Yang Y C.Observation&study of a kind of low-frequency atmospheric infrasonic waves.Acta Acustica(inChinese),2010,35(2):200-207.
[15]胡心康,石金瑞,任建国.大气中一种压力波动与地震关系的初步探索.地球物理学报,1980,23(4):450-458.Hu X K,Shi J R,Ren J G.Preliminary study of the relationbetween a kind of pressure waves in the atmosphere andearthquakes.Chinese J.Geophys.(in Chinese),1980,23(4):450-458.
[16]张贤达,保铮.非平稳信号分析与处理.北京:国防工业出版社,1998.Zhang X D,Bao Z.Non-stationary Signal Analysis andProcessing(in Chinese).Beijing:National Defence IndustryPress,1998.
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