利用GPS和DEMETER数据分析汶川地震前电离层变化
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摘要
利用GPSTEC和法国DEMETER卫星ISL探测器的观测数据,分析了汶川地震前电离层变化。结果表明,电离层TEC在5月6—10日地方时下午有连续的负异常现象,5月9日地方时下午有明显的正异常现象。电离层TEC异常的范围主要位于震中南部区域,EW方向上1100～1670km,SN方向上1600～3700km。5月6日的负异常偏震中东南,5月7日的负异常偏震中西南,5月9日的正异常偏震中东南。震中西南和南部地区负异常较东南地区明显,震中南部和东南地区正异常程度较西南地区偏高,震中位置所对应南半球磁力线共轭区都出现了一定程度的正或负扰动。DEME-TER卫星观测的电子密度Ne和离子密度Ni在5月6—10日也出现了明显的负异常,异常分布与电离层TEC异常分布较为一致,主要集中在震中南部。震中所在的经度带上存在2个负异常峰值,且在纬度上关于地磁赤道对称。最后在上述异常的基础上,对基于岩石圈—大气层—电离层耦合的地震电离层异常机理开展了初步讨论。
Based on GPS TEC data and ISL detector data recorded by the French DEMETER satellite,ionospheric perturbations before the Wenchuan earthquake were analyzed.It is found that GPS TEC above the epicenter continuously decreased in the afternoon period during 6 May to 10 May but increased in the afternoon of 9 May.The spatial distribution of the TEC anomaly mainly located in the south of the epicenter,and the size of perturbation area was 1 100 ～ 1 670km and 1 600 ～ 3 700km from the epicenter in the latitudinal and longitudinal directions,respectively.It is further found that negative anomaly area located southeast on 6 May and moved to southwest on 7 May from epicenter.On 9 May,the anomaly turned to be positive and occurred in the southeast of the epicenter.The intensity of negative anomaly in the southwest or south area from epicenter was stronger than that in the southeast area,compared with the southwest area,the intensity of positive anomaly in southeast or south area was stronger.Moreover,it could be seen that the perturbation was also observed in the geomagnetic conjugate points of epicenter at the southern hemisphere.In addition,contour analysis on ionopheric plasma shows that electron density(Ne) and ion density(Ni) also reduced during 6 to 10 May.The anomalous distribution was in good conformity with TEC,which was concentrated mainly in the south of epicenter.There were two negative anomaly peaks along the earthquake longitude,which were symmetrical about the magnetic equator.Base on the above observation,we finally discuss the physical mechanism of the seismoionospheric anomaly according to Lithosphere-Atmosphere-Ionosphere Couling(LAIC) model.
Based on GPS TEC data and ISL detector data recorded by the French DEMETER satellite,ionospheric perturbations before the Wenchuan earthquake were analyzed.It is found that GPS TEC above the epicenter continuously decreased in the afternoon period during 6 May to 10 May but increased in the afternoon of 9 May.The spatial distribution of the TEC anomaly mainly located in the south of the epicenter,and the size of perturbation area was 1 100 ～ 1 670km and 1 600 ～ 3 700km from the epicenter in the latitudinal and longitudinal directions,respectively.It is further found that negative anomaly area located southeast on 6 May and moved to southwest on 7 May from epicenter.On 9 May,the anomaly turned to be positive and occurred in the southeast of the epicenter.The intensity of negative anomaly in the southwest or south area from epicenter was stronger than that in the southeast area,compared with the southwest area,the intensity of positive anomaly in southeast or south area was stronger.Moreover,it could be seen that the perturbation was also observed in the geomagnetic conjugate points of epicenter at the southern hemisphere.In addition,contour analysis on ionopheric plasma shows that electron density(Ne) and ion density(Ni) also reduced during 6 to 10 May.The anomalous distribution was in good conformity with TEC,which was concentrated mainly in the south of epicenter.There were two negative anomaly peaks along the earthquake longitude,which were symmetrical about the magnetic equator.Base on the above observation,we finally discuss the physical mechanism of the seismoionospheric anomaly according to Lithosphere-Atmosphere-Ionosphere Couling(LAIC) model.
引文
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Berthelier J J,Godefroy M,Leblanc F,et al.2006b.IAP,the thermal plasma analyzer on DEMETER[J].Planetary andSpace Science,54(2006):487—501.
Dobrovolsky I P,Zubkov SⅠ,Miachkin VⅠ.1979.Estimation of the size of earthquake preparation zones[J].PureAppl Geophys,117:1025—1044.
Fenoglio M A,Johnston M J S,Byerlee J D.1995.Magnetic and electric fields associated with changes in high porepressure in fault zones:Application to the Loma Prieta ULF emissions[J].J Geophys Res,100(B7),12,951—12,958.
Freund F.2000.Time-resolved study of charge generation and propagation in igneous rocks[J].J Geophys Res,105(B5),11,001—11,019.
Freund F,Takeuchi A,et al.2004.Stress-induced changes in the electrical conductivity of igneous rocks and the generation of ground currents[J].Terrestrial Atmospheric and Oceanic Sciences,15(3):437—468.
Grimalsky V,KremenetskyⅠ,et al.1999.Excitation of electromagnetic waves in the lithosphere and their penetrationinto ionosphere and magnetosphere[J].J Atmos Electr,19(2):101—117.
Hayakawa M,Molchanov O A,et al.2004.Summary report of NASDA's earthquake remote sensing frontier project[J].Physics and Chemistry of the Earth,29:617—625.
Huang Q.2002.One possible generation mechanism of co-seismic electric signals[J].Proceedings of the Japan Academy(Ser B:Physical and Biological Sciences),78(7):173—178.
Lebreton J P,Stverak S,Travnicek P,et al.2006.The ISL Langmuir Probe experiment and its data processing onboardDEMETER:Scientific objectives,description and first results[J].Planet Space Sci,54:472—486.
Liu J Y,Chen YⅠ,Pulinets S A,et al.2000.Seismo-ionospheric signatures prior to M≥6.0Taiwan earthquakes[J].Geophys Res Lett,27(19):3113—3116.
Liu J Y,Chen YⅠ,Jhuang H K,et al.2004a.Ionospheric foF2and TEC anomalous days associated with M≥5.0earthquakes in Taiwan during1997-1999[J].Terr Atmos Ocean Sci,15:371—383.
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Liu J Y,Chen YⅠ,Chuo Y J,et al.2006.A statistical investigation of preearthquake ionospheric anomaly[J].J Geophys Res,111,A05304.doi:10.1029/2005JA011333.
Liu J Y,Chen YⅠ,Chen C H,et al.2009.Seismoionospheric GPS total electron content anomalies observed before the12May,2008MW7.9Wenchuan earthquake[J].J Geophys Res,114,A04320.doi:10.1029/2008JA013698.
Liu J Y,Chen YⅠ,Chen C H,et al.2010.Temporal and spatial precursors in the ionospheric global positioning system(GPS)total electron content observed before the26December2004M9.3Sumatra-Andaman Earthquake[J].JGeophys Res,115,A09312.doi:10.1029/2010JA015313.
Mishima T,Hirono T,Nakamura N,et al.2009.Changes to magnetic minerals caused by frictional heating during the1999Taiwan Chi-Chi earthquake[J].Earth Planets Space,61(6):797—801.
Molchanov O A,Hayakawa M.1995a.Generation of ULF electromagnetic emissions by microfracturing[J].GeophysRes Lett,22(22):3091—3094.
Molchanov O A,Hayakawa M,Rafalsky V A.1995b.Penetration characteristics of electromagnetic emissions from anunderground seismic source into the atmosphere,ionosphere,and magnetosphere[J].J Geophys Res,100(A2):1691—1712.
Molchanov O A,Schekotov A,Fedorov E,et al.2003.Preseismic ULF electromagnetic effect from observation at Kamchatka[J].Nat Hazards Earth Syst Sci,3:203—209.
Parrot M.1994.Statistical study of ELF/VLF emissions recorded by a low-altitude satellite during seismic events[J].J Geophys Res,99(A12):23,339—23,347.
Parrot M.2002,The micro-satellite DEMETER[J].Journal of Geodynamics,33(4-5):535—541.
Parrot M,Benoist D,Berthelier J J,et al.2006.The magnetic field experiment IMSC and its data processing onboardDEMETER:Scientific objectives,description and first results[J].Planetary and Space Science,54(5):441—455.
Pulinets S A,Legen A D,Gaivoronskaya T V,et al.2003.Main phenomenological features of ionospheric precursors ofstrong earthquakes[J].J Atmos Sol-terr Phy,65:1337—1347.
Pulinets S A.2004.Ionospheric precursors of earthquakes:Recent advances in theory and practical applications[J].Terrestrial Atmospheric and Oceanic Sciences,15(3):413—436.
Rozhnoi A,Solovieva M S,Molchanov O A,et al.2004.Middle latitude LF(40kHz)phase variations associated withearthquakes for quiet and disturbed geomagnetic conditions[J].Physics and Chemistry of the Earth,Parts A/B/C,29(4-9):589—598.
Sauvaud J A,Moreau T,Maggiolo R,et al.2006.High energy electron detection onboard DEMETER:The IDP spectrometer,description and first results on the inner belt[J].Planet Space Sci,54(5):502—511.
Sorokin V,Chmyrev V,Yaschenko A.2001.Electrodynamic model of the lower atmosphere and the ionosphere coupling[J].Journal of Atmospheric and Solar-terrestrial Physics,63(16):1681—1691.
Trigunait A,Parrot M,Pulinets S,et al.2004.Variations of the ionospheric electron density during the Bhuj seismic event[J].Annales Geophysicae,22:4123—4131.
Takeuchi A,Lau B,Freund F.2006.Current and surface potential induced by stress-activated positive holes in igneousrocks[J].Physics and Chemistry of the Earth,31(4-9):240—247.
Yu T,Mao T,Wang Y G,et al.2009.Study of the ionospheric anomaly before the Wenchuan earthquake[J].ChineseScience Bulletin,54(6):1080—1086.
Zakharenkova I E,Krankowski K,Shagimuratov IⅠ.2006.Modification of the low-latitude ionosphere before the26December2004Indonesian earthquake[J].Nat Hazards Earth Syst Sci,6:817—823.
Zhang X,Shen X,Liu J,et al.2009.Analysis of ionospheric plasma perturbations before Wenchuan earthquake[J].NatHazards Earth Syst Sci,9:1259—1266.
Zhao B,Wang M,Yu T,et al.2008.Is an unusual large enhancement of ionospheric electron density linked with the2008great Wenchuan earthquake?[J]J Geophys Res,113,A11304.doi:10.1029/2008JA013613.
Zlotnicki J,Cornet F H.1986.A numerical model of earthquake-induced piezomagnetic anomalies[J].J Geophys Res,91(B1):709—718.
Berthelier J J,Godefroy M,Leblanc F,et al.2006a.ICE,the electric field experiment on DEMETER[J].Planetary andSpace Science,54(2006):456—471.
Berthelier J J,Godefroy M,Leblanc F,et al.2006b.IAP,the thermal plasma analyzer on DEMETER[J].Planetary andSpace Science,54(2006):487—501.
Dobrovolsky I P,Zubkov SⅠ,Miachkin VⅠ.1979.Estimation of the size of earthquake preparation zones[J].PureAppl Geophys,117:1025—1044.
Fenoglio M A,Johnston M J S,Byerlee J D.1995.Magnetic and electric fields associated with changes in high porepressure in fault zones:Application to the Loma Prieta ULF emissions[J].J Geophys Res,100(B7),12,951—12,958.
Freund F.2000.Time-resolved study of charge generation and propagation in igneous rocks[J].J Geophys Res,105(B5),11,001—11,019.
Freund F,Takeuchi A,et al.2004.Stress-induced changes in the electrical conductivity of igneous rocks and the generation of ground currents[J].Terrestrial Atmospheric and Oceanic Sciences,15(3):437—468.
Grimalsky V,KremenetskyⅠ,et al.1999.Excitation of electromagnetic waves in the lithosphere and their penetrationinto ionosphere and magnetosphere[J].J Atmos Electr,19(2):101—117.
Hayakawa M,Molchanov O A,et al.2004.Summary report of NASDA's earthquake remote sensing frontier project[J].Physics and Chemistry of the Earth,29:617—625.
Huang Q.2002.One possible generation mechanism of co-seismic electric signals[J].Proceedings of the Japan Academy(Ser B:Physical and Biological Sciences),78(7):173—178.
Lebreton J P,Stverak S,Travnicek P,et al.2006.The ISL Langmuir Probe experiment and its data processing onboardDEMETER:Scientific objectives,description and first results[J].Planet Space Sci,54:472—486.
Liu J Y,Chen YⅠ,Pulinets S A,et al.2000.Seismo-ionospheric signatures prior to M≥6.0Taiwan earthquakes[J].Geophys Res Lett,27(19):3113—3116.
Liu J Y,Chen YⅠ,Jhuang H K,et al.2004a.Ionospheric foF2and TEC anomalous days associated with M≥5.0earthquakes in Taiwan during1997-1999[J].Terr Atmos Ocean Sci,15:371—383.
Liu J Y,Chuo Y J,Shan S J,et al.2004b.Pre-earthquake ionospheric anomalies monitored by GPS TEC[J].An Geophys,22:1585—1593.
Liu J Y,Chen YⅠ,Chuo Y J,et al.2006.A statistical investigation of preearthquake ionospheric anomaly[J].J Geophys Res,111,A05304.doi:10.1029/2005JA011333.
Liu J Y,Chen YⅠ,Chen C H,et al.2009.Seismoionospheric GPS total electron content anomalies observed before the12May,2008MW7.9Wenchuan earthquake[J].J Geophys Res,114,A04320.doi:10.1029/2008JA013698.
Liu J Y,Chen YⅠ,Chen C H,et al.2010.Temporal and spatial precursors in the ionospheric global positioning system(GPS)total electron content observed before the26December2004M9.3Sumatra-Andaman Earthquake[J].JGeophys Res,115,A09312.doi:10.1029/2010JA015313.
Mishima T,Hirono T,Nakamura N,et al.2009.Changes to magnetic minerals caused by frictional heating during the1999Taiwan Chi-Chi earthquake[J].Earth Planets Space,61(6):797—801.
Molchanov O A,Hayakawa M.1995a.Generation of ULF electromagnetic emissions by microfracturing[J].GeophysRes Lett,22(22):3091—3094.
Molchanov O A,Hayakawa M,Rafalsky V A.1995b.Penetration characteristics of electromagnetic emissions from anunderground seismic source into the atmosphere,ionosphere,and magnetosphere[J].J Geophys Res,100(A2):1691—1712.
Molchanov O A,Schekotov A,Fedorov E,et al.2003.Preseismic ULF electromagnetic effect from observation at Kamchatka[J].Nat Hazards Earth Syst Sci,3:203—209.
Parrot M.1994.Statistical study of ELF/VLF emissions recorded by a low-altitude satellite during seismic events[J].J Geophys Res,99(A12):23,339—23,347.
Parrot M.2002,The micro-satellite DEMETER[J].Journal of Geodynamics,33(4-5):535—541.
Parrot M,Benoist D,Berthelier J J,et al.2006.The magnetic field experiment IMSC and its data processing onboardDEMETER:Scientific objectives,description and first results[J].Planetary and Space Science,54(5):441—455.
Pulinets S A,Legen A D,Gaivoronskaya T V,et al.2003.Main phenomenological features of ionospheric precursors ofstrong earthquakes[J].J Atmos Sol-terr Phy,65:1337—1347.
Pulinets S A.2004.Ionospheric precursors of earthquakes:Recent advances in theory and practical applications[J].Terrestrial Atmospheric and Oceanic Sciences,15(3):413—436.
Rozhnoi A,Solovieva M S,Molchanov O A,et al.2004.Middle latitude LF(40kHz)phase variations associated withearthquakes for quiet and disturbed geomagnetic conditions[J].Physics and Chemistry of the Earth,Parts A/B/C,29(4-9):589—598.
Sauvaud J A,Moreau T,Maggiolo R,et al.2006.High energy electron detection onboard DEMETER:The IDP spectrometer,description and first results on the inner belt[J].Planet Space Sci,54(5):502—511.
Sorokin V,Chmyrev V,Yaschenko A.2001.Electrodynamic model of the lower atmosphere and the ionosphere coupling[J].Journal of Atmospheric and Solar-terrestrial Physics,63(16):1681—1691.
Trigunait A,Parrot M,Pulinets S,et al.2004.Variations of the ionospheric electron density during the Bhuj seismic event[J].Annales Geophysicae,22:4123—4131.
Takeuchi A,Lau B,Freund F.2006.Current and surface potential induced by stress-activated positive holes in igneousrocks[J].Physics and Chemistry of the Earth,31(4-9):240—247.
Yu T,Mao T,Wang Y G,et al.2009.Study of the ionospheric anomaly before the Wenchuan earthquake[J].ChineseScience Bulletin,54(6):1080—1086.
Zakharenkova I E,Krankowski K,Shagimuratov IⅠ.2006.Modification of the low-latitude ionosphere before the26December2004Indonesian earthquake[J].Nat Hazards Earth Syst Sci,6:817—823.
Zhang X,Shen X,Liu J,et al.2009.Analysis of ionospheric plasma perturbations before Wenchuan earthquake[J].NatHazards Earth Syst Sci,9:1259—1266.
Zhao B,Wang M,Yu T,et al.2008.Is an unusual large enhancement of ionospheric electron density linked with the2008great Wenchuan earthquake?[J]J Geophys Res,113,A11304.doi:10.1029/2008JA013613.
Zlotnicki J,Cornet F H.1986.A numerical model of earthquake-induced piezomagnetic anomalies[J].J Geophys Res,91(B1):709—718.
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