联合Envisat和ALOS卫星影像确定L′Aquila地震震源机制
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摘要
2009年4月6日意大利L′Aquila地区发生了Mw6.3级地震,该地震造成了300余人的人员死亡.本文联合不同波长、不同入射倾角的升降轨Envisat和ALOS卫星的差分干涉数据对该地震进行震源机制解的反演研究.研究首先对卫星雷达影像进行二通差分干涉处理,获取了覆盖L′Aquila地震震区的完整InSAR同震形变场,然后结合四叉树和均匀采样方法对原始观测数据进行降采样.在此基础上,联合GPS形变观测数据,利用弹性半空间矩形和三角位错模型,以及断层自动剖分技术对断层面进行最优离散剖分,反演获取了发震断层的精确几何参数和最优断层滑动分布,结果显示分布式三角位错滑动模型能够很好地解释观测到的地表形变场.反演结果表明发震断层是一个以正倾滑为主兼有少量右旋走滑的盲断层;基于观测数据最优确定的断层单元的最短边长为0.4km,最长边长为6.3km;此次地震的滑动分布主要发生在5～14km深度的范围内,最大滑移量为1.07m,释放的能量为3.43×1018 N.m(Mw6.32),与地震学的研究结果非常一致.
On the 6th April 2009,an Mw6.3 earthquake occurred in the region of L′Aqula of Italy,which caused more than 300 people to lose their lives.In this paper,the Envisat and ALOS satellite interferograms with different incidences and wavelengths are used to invert for the source parameters of the fault activated during the earthquake.Firstly,two-pass interferometry technique is used to obtain the coseismic deformation covering the whole epicenter region,then a combination method of quad-tree and uniform sample is employed to down-sample the original observed datasets.Secondly,the rectangle and triangle dislocation models in elastic half-space and an automated fault discretization method are used to derive the geometric and kinematic characteristic of fault combining with GPS surface displacement measurements.The best-fit solution shows that the distributed slip model can explain the data very well.The inversion result indicates that the fault is dominated by normal movement with small right-lateral strike-slip component.The shortest and longest length of the optimal fault patches based on the observing data are 0.4 km and 6.3 km,respectively.The fault slip concentrates mainly in the shallow depth between 5 km and 14 km,and the maximum slip is about 1.07 m.The inverted geodetic moment is 3.43×1018 N·m(Mw6.32),which is excellently consistent with the result of seismology.
On the 6th April 2009,an Mw6.3 earthquake occurred in the region of L′Aqula of Italy,which caused more than 300 people to lose their lives.In this paper,the Envisat and ALOS satellite interferograms with different incidences and wavelengths are used to invert for the source parameters of the fault activated during the earthquake.Firstly,two-pass interferometry technique is used to obtain the coseismic deformation covering the whole epicenter region,then a combination method of quad-tree and uniform sample is employed to down-sample the original observed datasets.Secondly,the rectangle and triangle dislocation models in elastic half-space and an automated fault discretization method are used to derive the geometric and kinematic characteristic of fault combining with GPS surface displacement measurements.The best-fit solution shows that the distributed slip model can explain the data very well.The inversion result indicates that the fault is dominated by normal movement with small right-lateral strike-slip component.The shortest and longest length of the optimal fault patches based on the observing data are 0.4 km and 6.3 km,respectively.The fault slip concentrates mainly in the shallow depth between 5 km and 14 km,and the maximum slip is about 1.07 m.The inverted geodetic moment is 3.43×1018 N·m(Mw6.32),which is excellently consistent with the result of seismology.
引文
[1]Walters R J,Elliott J R,D′Agostino N,et al.The2009L′Aquila Earthquake(Central Italy):a source mechanism and implications for seismic hazard.Geophys.Res.Lett.,2009,36:L17312,doi:10.1029/2009GL039337.
[2]Fialko Y,Sandwell D,Simons M,et al.Three-dimensional deformation caused by the Bam,Iran,earthquake and the origin of shallow slip deficit.Nature,2005,435(7040):295-299.
[3]Zhang G H,Qu C Y,Shan X J,et al.Slip distribution of the 2008Wenchuan M s 7.9earthquake by joint inversion from GPS and InSAR measurements:a resolution test study.Geophys.J.Int.,2011,186(1):207-220.
[4]Barnhart W D,Lohman R B.Automated fault model discretization for inversions for coseismic slip distributions.J.Geophys.Res.,2010,115:B10419,doi:10.1029/2010JB007545.
[5]Stucchi M,Camassi R,Rovida A,et al.DBMI04,il database delle osservazioni macrosismiche dei terremoti italiani utilizzate per la compilazione del catalogo parametrico CPTI04(in Italian),Quaderni Geofis.Ist.Naz.di Geofis.e Vulcanol.,Rome,2007.
[6]Hunstad I,Selvaggi G,D′Agostino N,et al.Geodetic strain in peninsular Italy between1875and2001.Geophys.Res.Lett.,2003,30(4),doi:10.1029/2002GL016447.
[7]D′Agostino N,Avallone A,Cheloni D,et al.Active tectonics of the Adriatic region from GPS and earthquake slip vectors.J.Geophys.Res.,2008,113(B12413),doi:10.1029/2008JB005860.
[8]Emergeo Working Group.Rilievi geologici di terreno effettuati nell′area epicentrale della sequenza sismica dell′Aquilano del6aprile2009.Ist.Naz.di Geofis.e Vulcanol.,Rome.2009(Available at http://www.earth-prints.org/handle/2122/5036[2010-8-13]).
[9]Anzidei M,Boschi E,Cannelli V,et al.Coseismic deformation of the destructive April6,2009L′Aquila earthquake(central Italy)from GPS data.Geophys.Res.Lett.,2009,36:L17307,doi:10.1029/2009GL039145.
[10]Cheloni D,D′Agostino N,D′Anastasio E,et al.Coseismic and initial post-seismic slip of the2009Mw6.3L′Aquila earthquake,Italy,from GPS measurements.Geophys.J.Int.,2010,181(3):1539-1546.
[11]Cirella A,Piatanesi A,Cocco M,et al.Rupture history of the2009L′Aquila(Italy)earthquake from non-linear joint inversion of strong motion and GPS data.Geophys.Res.Lett.,2009,36:L19304,doi:10.1029/2009GL039795.
[12]Pino N A,Di Luccio F.Source complexity of the6April 2009L′Aquila(central Italy)earthquake and its strongest aftershock revealed by elementary seismological analysis.Geophys.Res.Lett.,2009,36:L23305,doi:10.1029/2009GL041331.
[13]Bindi D,Pacor F,Luzi L,et al.The M w 6.3,2009L′Aquila earthquake:source,path and site effects from spectral analysis of strong motion data.Geophys.J.Int.,2009,179(3):1573-1579.
[14]Atzori S,Hunstad I,Chini M,et al.Finite fault inversion of DInSAR coseismic displacement of the2009L′Aquila earthquake(central Italy).Geophys.Res.Lett.,2009,36:L15305,doi:10.1029/2009GL039293.
[15]Massonnet D,Rossi M,Carmona C,et al.The displacement field of the Landers earthquake mapped by radar interferometry.Nature,1993,364(6433):138-142.
[16]Werner C L,Wegmüller U,Strozzi T,et al.GAMMA SAR and interferometry processing software.ERS ENVISAT Symp.,Gothenbury,Sweden,2000:16-20.
[17]Farr T G,Rosen P A,Caro E.The Shuttle RadarTopography Mission.Rev.Geophys.,2007,45:RG2004,doi:10.1029/2005RG000183.
[18]Goldstein R M,Werner C L.Radar interferogram filtering for geophysical applications.Geophys.Res.Lett.,1998,25(21):4035-4038.
[19]Hanssen R F.Radar Interferometric:Data Interpreatation and Error Analysis.New York:Kluwer Academic Publishers,2002.
[20]Parsons B,Wright T,Rowe P,et al.The1994Sefidabeh(eastern Iran)earthquakes revisited:new evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault.Geophys.J.Int.,2006,164(1):202-217.
[21]Jónsson S,Zebker H,Segall P,et al.Fault slip distribution of the1999M w 7.1Hector Mine,California,earthquake,estimated from satellite radar and GPS measurements.Bull.Seism.Soc.Am.,2002,92(4):1377-1389.
[22]Okada Y.Surface deformation due to shear and tensile faults in a half-space.Bull.Seism.Soc.Am.,1985,75(4):1135-1154.
[23]Meade B J.Algorithms for the calculation of exact displacements,strains,and stresses for triangular dislocation elements in a uniform elastic half space.Comput.Geosci.,2007,33(8):1064-1075.
[24]Lohman R B,Simons M.Some thoughts on the use of InSAR data to constrain models of surface deformation:noise structure and data downsampling.Geochem.Geophys.Geosyst.,2005,6:Q01007,doi:10.1029/2004GC000841.
[25]Clarke P J,Paradissis D,Briole P,et al.Geodetic investigation of the13May1995Kozani-Grevena(Greece)earthquake.Geophys.Res.Lett.,1997,24(6):707-710.
[26]Wright T J,Parsons B E,Jackson J A,et al.Source parameters of the1October1995Dinar(Turkey)earthquake from SAR interferometry and seismic bodywave modelling.Earth Planet.Sci.Lett.,1999,172(1-2):23-37.
[27]Du Y,Aydin A,Segall P.Comparison of various inversion techniques as applied to the determination of a geophysical deformation model for the1983Borah Peak earthquake.Bull.Seism.Soc.Am.,1992,82(4):1840-1866.
[28]Boncio P,Lavecchia G,Pace B.Defining a model of3D seismogenic sources for seismic hazard assessment applications:the case of central Apennines(Italy).J.Seismol.,2004,8(3):407-425.
[29]D′Agostino N,Giuliani R,Mattone M,et al.Active crustal extension in the Central Apennines(Italy)inferred from GPS measurements in the interval1994-1999.Geophys.Res.Lett.,2001,28(10):2121-2124.
[30]Galli P,Galadini F,Pantosti D.Twenty years of paleoseismology in Italy.Earth Sci.Rev.,2008,88(1-2):89-117.
[2]Fialko Y,Sandwell D,Simons M,et al.Three-dimensional deformation caused by the Bam,Iran,earthquake and the origin of shallow slip deficit.Nature,2005,435(7040):295-299.
[3]Zhang G H,Qu C Y,Shan X J,et al.Slip distribution of the 2008Wenchuan M s 7.9earthquake by joint inversion from GPS and InSAR measurements:a resolution test study.Geophys.J.Int.,2011,186(1):207-220.
[4]Barnhart W D,Lohman R B.Automated fault model discretization for inversions for coseismic slip distributions.J.Geophys.Res.,2010,115:B10419,doi:10.1029/2010JB007545.
[5]Stucchi M,Camassi R,Rovida A,et al.DBMI04,il database delle osservazioni macrosismiche dei terremoti italiani utilizzate per la compilazione del catalogo parametrico CPTI04(in Italian),Quaderni Geofis.Ist.Naz.di Geofis.e Vulcanol.,Rome,2007.
[6]Hunstad I,Selvaggi G,D′Agostino N,et al.Geodetic strain in peninsular Italy between1875and2001.Geophys.Res.Lett.,2003,30(4),doi:10.1029/2002GL016447.
[7]D′Agostino N,Avallone A,Cheloni D,et al.Active tectonics of the Adriatic region from GPS and earthquake slip vectors.J.Geophys.Res.,2008,113(B12413),doi:10.1029/2008JB005860.
[8]Emergeo Working Group.Rilievi geologici di terreno effettuati nell′area epicentrale della sequenza sismica dell′Aquilano del6aprile2009.Ist.Naz.di Geofis.e Vulcanol.,Rome.2009(Available at http://www.earth-prints.org/handle/2122/5036[2010-8-13]).
[9]Anzidei M,Boschi E,Cannelli V,et al.Coseismic deformation of the destructive April6,2009L′Aquila earthquake(central Italy)from GPS data.Geophys.Res.Lett.,2009,36:L17307,doi:10.1029/2009GL039145.
[10]Cheloni D,D′Agostino N,D′Anastasio E,et al.Coseismic and initial post-seismic slip of the2009Mw6.3L′Aquila earthquake,Italy,from GPS measurements.Geophys.J.Int.,2010,181(3):1539-1546.
[11]Cirella A,Piatanesi A,Cocco M,et al.Rupture history of the2009L′Aquila(Italy)earthquake from non-linear joint inversion of strong motion and GPS data.Geophys.Res.Lett.,2009,36:L19304,doi:10.1029/2009GL039795.
[12]Pino N A,Di Luccio F.Source complexity of the6April 2009L′Aquila(central Italy)earthquake and its strongest aftershock revealed by elementary seismological analysis.Geophys.Res.Lett.,2009,36:L23305,doi:10.1029/2009GL041331.
[13]Bindi D,Pacor F,Luzi L,et al.The M w 6.3,2009L′Aquila earthquake:source,path and site effects from spectral analysis of strong motion data.Geophys.J.Int.,2009,179(3):1573-1579.
[14]Atzori S,Hunstad I,Chini M,et al.Finite fault inversion of DInSAR coseismic displacement of the2009L′Aquila earthquake(central Italy).Geophys.Res.Lett.,2009,36:L15305,doi:10.1029/2009GL039293.
[15]Massonnet D,Rossi M,Carmona C,et al.The displacement field of the Landers earthquake mapped by radar interferometry.Nature,1993,364(6433):138-142.
[16]Werner C L,Wegmüller U,Strozzi T,et al.GAMMA SAR and interferometry processing software.ERS ENVISAT Symp.,Gothenbury,Sweden,2000:16-20.
[17]Farr T G,Rosen P A,Caro E.The Shuttle RadarTopography Mission.Rev.Geophys.,2007,45:RG2004,doi:10.1029/2005RG000183.
[18]Goldstein R M,Werner C L.Radar interferogram filtering for geophysical applications.Geophys.Res.Lett.,1998,25(21):4035-4038.
[19]Hanssen R F.Radar Interferometric:Data Interpreatation and Error Analysis.New York:Kluwer Academic Publishers,2002.
[20]Parsons B,Wright T,Rowe P,et al.The1994Sefidabeh(eastern Iran)earthquakes revisited:new evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault.Geophys.J.Int.,2006,164(1):202-217.
[21]Jónsson S,Zebker H,Segall P,et al.Fault slip distribution of the1999M w 7.1Hector Mine,California,earthquake,estimated from satellite radar and GPS measurements.Bull.Seism.Soc.Am.,2002,92(4):1377-1389.
[22]Okada Y.Surface deformation due to shear and tensile faults in a half-space.Bull.Seism.Soc.Am.,1985,75(4):1135-1154.
[23]Meade B J.Algorithms for the calculation of exact displacements,strains,and stresses for triangular dislocation elements in a uniform elastic half space.Comput.Geosci.,2007,33(8):1064-1075.
[24]Lohman R B,Simons M.Some thoughts on the use of InSAR data to constrain models of surface deformation:noise structure and data downsampling.Geochem.Geophys.Geosyst.,2005,6:Q01007,doi:10.1029/2004GC000841.
[25]Clarke P J,Paradissis D,Briole P,et al.Geodetic investigation of the13May1995Kozani-Grevena(Greece)earthquake.Geophys.Res.Lett.,1997,24(6):707-710.
[26]Wright T J,Parsons B E,Jackson J A,et al.Source parameters of the1October1995Dinar(Turkey)earthquake from SAR interferometry and seismic bodywave modelling.Earth Planet.Sci.Lett.,1999,172(1-2):23-37.
[27]Du Y,Aydin A,Segall P.Comparison of various inversion techniques as applied to the determination of a geophysical deformation model for the1983Borah Peak earthquake.Bull.Seism.Soc.Am.,1992,82(4):1840-1866.
[28]Boncio P,Lavecchia G,Pace B.Defining a model of3D seismogenic sources for seismic hazard assessment applications:the case of central Apennines(Italy).J.Seismol.,2004,8(3):407-425.
[29]D′Agostino N,Giuliani R,Mattone M,et al.Active crustal extension in the Central Apennines(Italy)inferred from GPS measurements in the interval1994-1999.Geophys.Res.Lett.,2001,28(10):2121-2124.
[30]Galli P,Galadini F,Pantosti D.Twenty years of paleoseismology in Italy.Earth Sci.Rev.,2008,88(1-2):89-117.
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