阿尔金东段现代变形特征的SAR监测
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摘要
合成孔径雷达差分干涉测量技术(D-InSAR)可监测地球表面的微量形变,包括地震、火山活动、冰川漂移、地面沉降、活动断裂及山体滑坡等引起的地表位移,是近年来发展起来并得到日益重视的新方法,与其他监测方法(如GPS监测等)相比,用D-InSAR进行地面微位移监测具有全天时、全天候、精度高、覆盖范围大且空间连续的巨大优势。采用D-InSAR技术对阿尔金东段构造变形特征进行了研究,结果表明,阿尔金断裂带是青藏高原东北缘地壳变形的重要分界线。界线以北地区变形均匀,而且变形量较小;以南地区变形强烈且不均匀,变形强度的总体趋势为西高东低,中间受北祁连断裂带西段的影响,在断裂带中出现约为1.0cm的变形低值。另外,南区存在N65°W和近NW两个方向的线性强变形带,前者与阿尔金走滑断裂带次一级的压扭面方向一致,后者与北祁连断裂带西段的展布方向一致。
In recent years,the differential Interferometric Synthetic Aperture Radar(D-InSAR)technique has been widely used in the earth's surface deformation monitoring,including the displacements caused by earthquake,volcano activity,glacier movement,ground subsidence,active fault and landslides.Compared with the conventional approaches(such as GPS monitoring),applying the D-InSAR technique has many advantages in surface deformation monitoring.Firstly,the SAR satellite works all the time,and it is not affected by climatic changes.Secondly,the spatial resolution is high.Thirdly,the images can cover a large area on the earth.Finally,the continuous displacement information of the ground can be achieved.In this paper,the D-InSAR technique is used to study the tectonic deformation characteristics of the eastern segment of the Altyn Tagh Fault,which is an important crustal deformation boundary on the northeastern margin of the Tibetan Plateau.To the north of this boundary,the surface deformation is weak and uniform,while to the south it is strong but not uniform.From the western part to the eastern part of this area,the deformation intensity gradually decreases.Between these two parts there is the western part of the North Qilianshan Fault,where the minimum deformation intensity is about 1.0 cm.In addition,there exist two linear intensive deformation belts in the southern area.One is in N65 W direction,which is in accordance with the direction of the secondary compression-shear plane of the Altyn Tagh strike-slip fault zone.The other is in a roughly NW direction,which is consistent with the trend of the western part of the North Qilianshan Fault.
In recent years,the differential Interferometric Synthetic Aperture Radar(D-InSAR)technique has been widely used in the earth's surface deformation monitoring,including the displacements caused by earthquake,volcano activity,glacier movement,ground subsidence,active fault and landslides.Compared with the conventional approaches(such as GPS monitoring),applying the D-InSAR technique has many advantages in surface deformation monitoring.Firstly,the SAR satellite works all the time,and it is not affected by climatic changes.Secondly,the spatial resolution is high.Thirdly,the images can cover a large area on the earth.Finally,the continuous displacement information of the ground can be achieved.In this paper,the D-InSAR technique is used to study the tectonic deformation characteristics of the eastern segment of the Altyn Tagh Fault,which is an important crustal deformation boundary on the northeastern margin of the Tibetan Plateau.To the north of this boundary,the surface deformation is weak and uniform,while to the south it is strong but not uniform.From the western part to the eastern part of this area,the deformation intensity gradually decreases.Between these two parts there is the western part of the North Qilianshan Fault,where the minimum deformation intensity is about 1.0 cm.In addition,there exist two linear intensive deformation belts in the southern area.One is in N65 W direction,which is in accordance with the direction of the secondary compression-shear plane of the Altyn Tagh strike-slip fault zone.The other is in a roughly NW direction,which is consistent with the trend of the western part of the North Qilianshan Fault.
引文
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[2]Massonnet D,Rossi M,Carmona C,et al.The displacement field of the landers earthquake mapped by radar interferome-try[J].Nature,1993,364:138-142.[doi:10.1038/369227a0]
[3]Benedicte F,Francesco S.Detection of ground subsidence in the city of Paris using radar interferometry:isolation of de-formation from at mospheric artifacts using correlation[J].Geophysical Research Letters,2000,27(24):3981-3984.[doi:10.1029/2000GL008489]
[4]Lu Z,Wicks C,Dzurisin D,et al.Aseismic inflation of Westdahl volcano,Alaska,revealed by satellite radar inter-ferometry[J].Geophysical Research Letters,2000,27(11):1567-1570.
[5]Fialko Y,Sandwell D,Si mons M,et al.Three-di mensional deformation caused by the Bam,Iran,earthquake and the or-igin of shallowslip deficit[J].Nature,2005,435:295-299.[doi:10.1038/nature03425]
[6]Bürgmann R,Hilley G,Ferretti A,et al.Resolving vertical tectonics in the San Francisco Bay Area frompermanent scat-terer InSARand GPS analysis[J].Geology,2006,34(3):221-224.
[7]Massonnet D,Holzer T,Vadon H.Land subsidence caused by the East Mesa geothermal field,Calfornia,observed using SAR interferometry[J].Geophysical Research Letters,1997,24(8):901-904.
[8]Fuji wara S,Rosen P A,Tobita M,et al.Crustal deforma-tion measurements using repeat-pass JERS-1synthetic aper-ture radar interferometry near Izu peninsula[J].Journal of Geophysical Research,1998,103(B2):2411-2426.
[9]Nakagawa H,Murakami M,Fuji wara S,et al.Land subsid-ence of the northern Kanto Plains caused by ground water ex-traction detected by JERS-1SARinterferometry[J].Interna-tional Geoscience and Remote Sensing Symposium,2000,5:2233-2235.
[10]Shan J X,Ma J,Wang C L,et al.Obtainfocal parameters of Mani Earthquake using ground deformation field by space-borne D-InSAR[J].Science in China:Series D,2002,32(10):837-844.
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