地磁日变与地震活动关系的主成分分析——以日本岩手县北部6.1级地震为例
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摘要
本文提出了将主成分分析方法和地磁日变分析方法相结合以从较强干扰背景中提取相对较弱地震地磁信息的一种新思路.具体以1 998年日本岩手县北部6.1级地震为例,选用三个地磁观测台资料进行研究.利用调和分析方法得到了各台基于多次谐波拟合的地磁日变曲线,在此基础上对各台的地磁日变形态进行了研究,发现距震中最近地磁台的日变形态在地震前大约两周出现了明显的异常,而其他两个距离震中相对较远的观测台日变形态基本正常.最后,将主成分分析方法应用于上述拟合地磁日变结果,得到了各主成分及其所占能量比的时间变化,结果表明在地震前两周左右第二主成分所占能量比显著增加,而且距离震中最近的台站的上述变化明显高于另两个较远的台站.上二述结果表明地震前两周左右检测到的地磁日变异常可能与震中附近地下电阻率的变化或孕震过程中产生的电磁信号存在一定关系,相关研究结果有助于加深对地震电磁现象的认识和理解.
This study provides a new seismomagnetic data processing method by combining principal component analysis (PCA) and geomagnetic diurnal variation analysis.As a case study, we investigated the geomagnetic data observed at Matsukawa,Kakioka,and Memambetsu stations and discussed their relationship with the M6.1 Iwate-ken Nairiku Hokubu earthquake occurred in 1998.The results showed that there is a clear anomaly of the geomagnetic diurnal variations about two weeks before the mainshock at Matsukawa station,which is only 15 km away from the epicenter.After applying the PCA method to the geomagnetic diurnal data,we investigated the temporal variations of the contribution of each principal component.The results indicated that the contribution of the 2~(nd) principal components,which may relate with the local underground conductivity structure and/or the local electromagnetic disturbance possibly due to the local seismogenic process,increased significantly about two weeks before the earthquake. These results are consistent with those obtained independently from the previous case studies by using polarization analysis method.This study may strengthen the understanding of seismoelectromagnetic phenomena.
This study provides a new seismomagnetic data processing method by combining principal component analysis (PCA) and geomagnetic diurnal variation analysis.As a case study, we investigated the geomagnetic data observed at Matsukawa,Kakioka,and Memambetsu stations and discussed their relationship with the M6.1 Iwate-ken Nairiku Hokubu earthquake occurred in 1998.The results showed that there is a clear anomaly of the geomagnetic diurnal variations about two weeks before the mainshock at Matsukawa station,which is only 15 km away from the epicenter.After applying the PCA method to the geomagnetic diurnal data,we investigated the temporal variations of the contribution of each principal component.The results indicated that the contribution of the 2~(nd) principal components,which may relate with the local underground conductivity structure and/or the local electromagnetic disturbance possibly due to the local seismogenic process,increased significantly about two weeks before the earthquake. These results are consistent with those obtained independently from the previous case studies by using polarization analysis method.This study may strengthen the understanding of seismoelectromagnetic phenomena.
引文
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[2] Uyeda S,Hayakawa M,Nagao T,et al.Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region,Japan.Proc.Natl.Acad.Sci.USA,2002,99(11) :7352-7355
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[5] 黄清华,刘涛.新岛台地电场的潮汐响应与地震.地球物理学报,2006,49(6) :1745～1754 Huang Q H,Liu T.Earthquakes and tide response of geoelectric potential field at the Niijima station.Chinese J.Geophys.(in Chinese),2006,49(6) :1745-1754
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[8] Huang Q.One possible generation mechanism of co seismic electric signals.Prec.Japan Acad.,2002,78(B7) :173-I78
[9] Huang Q. Theoretical and experimental study on seismoelectric signals and earthquake related phenomena [Ph.D.thesis],Japan;Osaka Univ.,1999． 107
[10] Huang Q,Ikeya M.Seismic electromagnetic signals (SEMS) explained by a simulation experiment using electromagnetic waves.Phys.Earth Planet.Inter.,1998,109(3--4) :107-114
[11] Du A,Huang Q,Yang S.Epicenter location by abnormal ULF electromagnetic emissions.Geophys.Res.Lett.,2002,29(10) :1455,doi:10． 1029/2001GL013616
[12] Huang Q,Ikeya M.Experimental study on the propagation of seismic electromagnetic signal (SEMS) using a mini geographic model of the Taiwan strait.Episodes,1999,22(4) :289-294
[13] Huang Q H.Controlled analogue experiments on propagation of seismic electromagnetic signals.Chinese Science Bulletin,2005,50(17) :1956-1961
[14] 丁鉴海,卢振业,黄雪香.地震电磁学.北京:地震出版社,1994 Ding J H,Lu Z Y,Huang X X.Seismic Electromagnetism (in Chinese).Beijing:Seismological Press,1994
[15] 钱家栋,林云芳主编.地震电磁观测技术.北京:地震出版社,1995 Qian J D,Lin Y F eds. Technology of Seismic Electromagnetic Observation (in Chinese ). Beijing:Seismological Press,1995
[16] Hattori K,Takahashi I,Yoshino C,et al.ULF geomagnetic field measurements in japan and some recent results associated with Iwateken Nairiku Hokubu earthquake in 1998． Physics and Chemistry of the Earth,2004,29 (4--9) :481-494
[17] Telesca L,Hattori K.Non-uniform scaling behavior in ultra low-frequency (ULF) earthquake-related geomagnetic signals.Physica A,2007,384(2) :522-528
[18] Ida Y,Hayakawa M.Fractal analysis for the ULF data during the 1993 Guam earthquake to study prefracture criticality.Nonlinear Processes in Geophysics,2006,13:409-412
[19] Alpemvich L,Zheludev V,Hayakawa M.Use of wavelet analysis for detection of geomagnetic ULF emissions.Radio Science,2003,38(6) :1093,10． 1029/2002RS002687
[20] 李琪,林云芳,曾小苹.应用小波变换提取张北地震的震磁效应.地球物理学报,2006,49(3) :855～863 Li Q,Lin Y F,Zeng X P.Wavelet analysis as a tool for revealing geomagnetic precursors of the Zhanghei earthquake.Chinese J.Geophys.(in Chinese),2006,49(3) :855-863
[21] Hattori K,Serita A,Gotoh K.ULF geomagnetic anomaly associated with 2000 Izu Islands earthquake swarm,Japan.Physics and Chemistry of the Earth,2004,29(4-9) :425-435
[22] 王亶文.地磁日变规律的破坏与地震的关系研究.地震地磁观测与研究,2003,24(1) :1～6 Wang T W.The investigation of the relations between the geomagnetic daily change and the earthquake.Seismological and Geomagnetic Observation and Research (in Chinese),2003,24(1) :1-6
[23] 徐文耀.地磁学.北京:地震出版社,2003 Xu W Y.Geomagnetism (in Chinese).Beijing:Seismological Press,2003
[24] 李卫东.应用多元统计分析.北京:北京大学出版社,2008 Li W D.Applied Multivariate Statistical Analysis (in Chinese).Being:Peking University Press,2008
[25] Mizutani H,Ishido T,Yokokura T,et al.Electrokinetic phenomena associated with earthquakes.Geophys.Res.Lett.,1976,3(7) :365-368
[2] Uyeda S,Hayakawa M,Nagao T,et al.Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region,Japan.Proc.Natl.Acad.Sci.USA,2002,99(11) :7352-7355
[3] Johnston M.Review of electric and magnetic fields accompanying seismic and volcanic activity.Surveys in Geophysics,1997,18:441-476
[4] Fraser-Smith A C,Bernardi A,McGill P R,et al.Low-frequency magnetic field measurements near the epicenter of the M_S7． 1 Loma Prieta earthquake.Geophys.Res.Lett.,1990,17(9) :1465-1468
[5] 黄清华,刘涛.新岛台地电场的潮汐响应与地震.地球物理学报,2006,49(6) :1745～1754 Huang Q H,Liu T.Earthquakes and tide response of geoelectric potential field at the Niijima station.Chinese J.Geophys.(in Chinese),2006,49(6) :1745-1754
[6] 郭自强,罗祥麟,钱书清等.矿山爆炸中的电磁辐射.地球 物理学报,1999,42(6) :834～840 Guo Z Q,Luo X L,Qian S Q,et al.Electromagnetic emission accompanying mine blasting.Chinese J.Geophys.(in Chinese),1999,42(6) :834-840
[7] 郝锦绮,钱书清,高金田等.岩石破裂过程中的超低频电磁异常.地震学报,2003,25(1) :102～111 Hao J Q,Qian S Q,Gao J T,et al.ULF electric and magnetic anomalies accompanying the cracking of rock sample.Acta Seismologica Sinica (in Chinese),2003,25(1) :102-111
[8] Huang Q.One possible generation mechanism of co seismic electric signals.Prec.Japan Acad.,2002,78(B7) :173-I78
[9] Huang Q. Theoretical and experimental study on seismoelectric signals and earthquake related phenomena [Ph.D.thesis],Japan;Osaka Univ.,1999． 107
[10] Huang Q,Ikeya M.Seismic electromagnetic signals (SEMS) explained by a simulation experiment using electromagnetic waves.Phys.Earth Planet.Inter.,1998,109(3--4) :107-114
[11] Du A,Huang Q,Yang S.Epicenter location by abnormal ULF electromagnetic emissions.Geophys.Res.Lett.,2002,29(10) :1455,doi:10． 1029/2001GL013616
[12] Huang Q,Ikeya M.Experimental study on the propagation of seismic electromagnetic signal (SEMS) using a mini geographic model of the Taiwan strait.Episodes,1999,22(4) :289-294
[13] Huang Q H.Controlled analogue experiments on propagation of seismic electromagnetic signals.Chinese Science Bulletin,2005,50(17) :1956-1961
[14] 丁鉴海,卢振业,黄雪香.地震电磁学.北京:地震出版社,1994 Ding J H,Lu Z Y,Huang X X.Seismic Electromagnetism (in Chinese).Beijing:Seismological Press,1994
[15] 钱家栋,林云芳主编.地震电磁观测技术.北京:地震出版社,1995 Qian J D,Lin Y F eds. Technology of Seismic Electromagnetic Observation (in Chinese ). Beijing:Seismological Press,1995
[16] Hattori K,Takahashi I,Yoshino C,et al.ULF geomagnetic field measurements in japan and some recent results associated with Iwateken Nairiku Hokubu earthquake in 1998． Physics and Chemistry of the Earth,2004,29 (4--9) :481-494
[17] Telesca L,Hattori K.Non-uniform scaling behavior in ultra low-frequency (ULF) earthquake-related geomagnetic signals.Physica A,2007,384(2) :522-528
[18] Ida Y,Hayakawa M.Fractal analysis for the ULF data during the 1993 Guam earthquake to study prefracture criticality.Nonlinear Processes in Geophysics,2006,13:409-412
[19] Alpemvich L,Zheludev V,Hayakawa M.Use of wavelet analysis for detection of geomagnetic ULF emissions.Radio Science,2003,38(6) :1093,10． 1029/2002RS002687
[20] 李琪,林云芳,曾小苹.应用小波变换提取张北地震的震磁效应.地球物理学报,2006,49(3) :855～863 Li Q,Lin Y F,Zeng X P.Wavelet analysis as a tool for revealing geomagnetic precursors of the Zhanghei earthquake.Chinese J.Geophys.(in Chinese),2006,49(3) :855-863
[21] Hattori K,Serita A,Gotoh K.ULF geomagnetic anomaly associated with 2000 Izu Islands earthquake swarm,Japan.Physics and Chemistry of the Earth,2004,29(4-9) :425-435
[22] 王亶文.地磁日变规律的破坏与地震的关系研究.地震地磁观测与研究,2003,24(1) :1～6 Wang T W.The investigation of the relations between the geomagnetic daily change and the earthquake.Seismological and Geomagnetic Observation and Research (in Chinese),2003,24(1) :1-6
[23] 徐文耀.地磁学.北京:地震出版社,2003 Xu W Y.Geomagnetism (in Chinese).Beijing:Seismological Press,2003
[24] 李卫东.应用多元统计分析.北京:北京大学出版社,2008 Li W D.Applied Multivariate Statistical Analysis (in Chinese).Being:Peking University Press,2008
[25] Mizutani H,Ishido T,Yokokura T,et al.Electrokinetic phenomena associated with earthquakes.Geophys.Res.Lett.,1976,3(7) :365-368
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