利用GPS数据反演中国红河断裂带活动特性
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摘要
为了研究中国红河断裂带近年的活动特性,利用块体模型对红河断裂带周围块体内1999—2014年的GPS水平速度场进行建模,反演得到块体的刚体旋转、内部应变率以及断层的滑动速率与三维闭锁程度。结果表明,考虑内部应变的块体模型可以显著提升速度场的拟合效果,反演得到的红河断裂带滑动速率与二维速度剖面的结果吻合较好。红河断裂带的闭锁程度大致呈现中段闭锁较强、南段与北段闭锁较弱的对称分布,南段、中段与北段在地表以下15 km深度范围内的断层闭锁程度分别约为0.34～0.52、0.67～0.75、0.26～0.53,右旋滑动亏损速率分别为1.7、3.0、1.4 mm/a。利用最小二乘配置方法计算了研究区域的应变场分布,发现红河断裂带从南至北由压缩转换为拉张,中段处于压缩与拉张的交界带,剪应变率低于南北两段,这可能是由于中段闭锁较强、断层错动量较小造成的。
In order to study the activity characteristics of the Red River fault zone in recent years, the GPS measurements from 1999 to 2014 in the surrounding blocks of the Red River fault zone are modeled by block model, and the rigid block rotations, internal strain rates, fault slip rates and three-dimensional locking degree are obtained. The inversion results show that the block model considering the internal strain can significantly improve the fitting effect to the GPS velocities, the inverted slip rates of the Red River fault are in good agreement with the results of the velocity profiles. The locking degree of the Red River fault is roughly symmetrical that the middle section is relatively strong, and the southern and northern segments are weak. The locking degree of the southern, middle and northern sections are about 0.34-0.52, 0.67-0.75 and0.26-0.53 respectively from the surface to 15 km depth, and the dextral slip rate deficit were 1.7, 3.0 and1.4 mm/a, respectively. The distribution of strain field in the study area is calculated by the least squares collocation, it is found that the Red River fault zone is converted from compression in the south to tension in the north. The middle section is in the transfer zone of compression and tension, and its shear strain is lower than the northern and southern sections, which may be due to the stronger locking degree of the middle, so that the fault dislocation is smaller.
In order to study the activity characteristics of the Red River fault zone in recent years, the GPS measurements from 1999 to 2014 in the surrounding blocks of the Red River fault zone are modeled by block model, and the rigid block rotations, internal strain rates, fault slip rates and three-dimensional locking degree are obtained. The inversion results show that the block model considering the internal strain can significantly improve the fitting effect to the GPS velocities, the inverted slip rates of the Red River fault are in good agreement with the results of the velocity profiles. The locking degree of the Red River fault is roughly symmetrical that the middle section is relatively strong, and the southern and northern segments are weak. The locking degree of the southern, middle and northern sections are about 0.34-0.52, 0.67-0.75 and0.26-0.53 respectively from the surface to 15 km depth, and the dextral slip rate deficit were 1.7, 3.0 and1.4 mm/a, respectively. The distribution of strain field in the study area is calculated by the least squares collocation, it is found that the Red River fault zone is converted from compression in the south to tension in the north. The middle section is in the transfer zone of compression and tension, and its shear strain is lower than the northern and southern sections, which may be due to the stronger locking degree of the middle, so that the fault dislocation is smaller.
引文
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[17]Zhao Jing,Jiang Zaisen,Wu Yanqiang,et al.Study on Fault Locking and Fault Slip Deficit of the Longmenshan Fault Zone Before the Wenchuan Earthquake[J].Chinese J Geophys,2012,55(9):2 963-2 972(赵静,江在森,武艳强,等.汶川地震前龙门山断裂带闭锁程度和滑动亏损分布研究[J].地球物理学报,2012,55(9):2 963-2 972)
[18]Guo Shunmin,Xiang Hongfa,Ji Fengju,et al.AStudy on the Relation Between Quaternary RightLateral Slip and Tip Extension Along the Honghe Fault[J].Seismology and Geology,1996,18(4):301-309(虢顺民,向宏发,计凤桔,等.红河断裂带第四纪右旋走滑与尾端拉张转换关系研究[J].地震地质,1996,18(4):301-309)
[19]Allen C R,Gillespie A R,Han Yuan,et al.Red River and Associated Faults,Yunnan Province,China:Quaternary Geology,Slip Rates,and Seismic Hazard[J].Geological Society of America Bulletin,1984,95(6):686-700
[20]Wang Shuai,Xu Caijun,Wen Yangmao,et al.Slip Model for the 25 November 2016 Mw 6.6 Aketao Earthquake,Western China,Revealed by Sentinel-1and ALOS-2 Observations[J].Remote Sensing,2017,9(4):325,DOI:10.3390/rs9040325
[21]Wang Yiran,Li Youli,Si Supei.The Geometrical Characteristics of Offset Streams and the ShipingJianshui Fault Activity[J].Quaternary Sciences,2015,35(1):100-108(王怡然,李有利,司苏沛.石屏-建水断裂水平错断河流的几何特征与断层活动性研究[J].第四纪研究,2015,35(1):100-108)
[22]Jiang Zaisen,Liu Jingnan.The Method in Establishing Strain Field Velocity Field of Crustal Movement Using Least Squares Collection[J].Chinese J Geophys,2010,53(5):1 109-1 117(江在森,刘经南.应用最小二乘配置建立地壳运动速度场与应变场的方法[J].地球物理学报,2010,53(5):1 109-1 117)
[2]Liu Yaohui,Li Jinping,Wang Liuwei.Inversion Study on Locking and Slip Deficit of Red River Fault Zone[J].Engineering of Surveying and Mapping,2015,24(8):20-22(刘耀辉,李金平,王刘伟.红河断裂带闭锁程度和滑动亏损分布特征研究[J].测绘工程,2015,24(8):20-22)
[3]Jiang Weiping,Zhou Xiaohui,Liu Jingnan,et al.Present-Day Crustal Movement and Strain Rate in the Qinghai-Tibetan Plateau from GPS Data[J].Acta Geodaetica et Cartographica Sinica,2008,37(3):285-292(姜卫平,周晓慧,刘经南,等.青藏高原地壳运动与应变的GPS监测研究[J].测绘学报,2008,37(3):285-292)
[4]Xiao Zhuohui,Xu Caijun,Jiang Guoyan,et al.Crustal Strain in the Longmenshan Region Considering Fault Locking During Ten Years Before the 2008 Wenchuan Earthquake[J].Chinese J Geophys,2017,60(3):953-961(肖卓辉,许才军,江国焰,等.汶川地震前十年间龙门山区域顾及断层闭锁的地壳应变场[J].地球物理学报,2017,60(3):953-961)
[5]Jiang Guoyan,Xu Xiwei,Chen Guihua,et al.Geodetic Imaging of Potential Seismogenic Asperities on the Xianshuihe-Anninghe-Zemuhe Fault System,Southwest China,with a New 3-D Viscoelastic Interseismic Coupling Model[J].J Geophys Res,2015,120(3):1 855-1 873
[6]Shen Zhengkang,LüJiangning,Wang Min,et al.Contemporary Crustal Deformation Around the Southeast Borderland of the Tibetan Plateau[J].JGeophys Res,2005,110(B11),DOI:10.1029/2004JB003421
[7]Wang Wei,Qiao Xuejun,Yang Shaomin,et al.PresentDay Velocity Field and Block Kinematics of Tibetan Plateau from GPS Measurements[J].Geophys J Int,2017,208(2):1 088-1 102
[8]Wang Yanzhao,Wang Enning,Shen Zhengkang,et al.GPS-Constrained Inversion of Present-Day Slip Rates Along Major Faults of the Sichuan-Yunnan Region,China[J].Science in China(Series D),2008,51(9):1 267-1 283
[9]Zhang Zhuqi,McCaffrey R,Zhang Peizhen.Relative Motion Across the Eastern Tibetan Plateau:Contributions from Faulting,Internal Strain and Rotation Rates[J].Tectonophysics,2013,584(1):240-256
[10]McCaffrey R.Block Kinematics of the Pacific-North America Plate Boundary in the Southwestern United States from Inversion of GPS,Seismological,and Geologic Data[J].J Geophys Res,2005,110(B7),DOI:10.1029/2004JB003307
[11]McCaffrey R.Crustal Block Rotations and Plate Coupling[M]//Stein S,Freymueller J T.AGUMonograph,Plate Boundary Zones.New York:John Wiley and Sons,2002
[12]Savage J C.A Dislocation Model of Strain Accumulation and Release at a Subduction Zone[J].J Geophys Res,1983,88(B6):4 984-4 996
[13]Savage J C,Gan W,Svarc J L.Strain Accumulation and Rotation in the Eastern California Shear Zone[J].J Geophys Res,2001,106(B10):21 995-22 007
[14]Zhang Peizhen,Deng Qidong,Zhang Guomin,et al.Strong Earthquakes and Active Blocks in Mainland China[J].Science in China(Series D),2003,33(z1):12-20(张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(z1):12-20)
[15]Deng Qidong,Zhang Peizhen,Ran Yongkang,et al.Basic Characteristics of Active Tectonics of China[J].Science in China(Series D),2003,46(4):356-372
[16]Mao A,Harrison C G A,Dixon T H.Noise in GPSCoordinate Time Series[J].Journal of Geophysical Research Atmospheres,1999,104(B2):2 797-2 816
[17]Zhao Jing,Jiang Zaisen,Wu Yanqiang,et al.Study on Fault Locking and Fault Slip Deficit of the Longmenshan Fault Zone Before the Wenchuan Earthquake[J].Chinese J Geophys,2012,55(9):2 963-2 972(赵静,江在森,武艳强,等.汶川地震前龙门山断裂带闭锁程度和滑动亏损分布研究[J].地球物理学报,2012,55(9):2 963-2 972)
[18]Guo Shunmin,Xiang Hongfa,Ji Fengju,et al.AStudy on the Relation Between Quaternary RightLateral Slip and Tip Extension Along the Honghe Fault[J].Seismology and Geology,1996,18(4):301-309(虢顺民,向宏发,计凤桔,等.红河断裂带第四纪右旋走滑与尾端拉张转换关系研究[J].地震地质,1996,18(4):301-309)
[19]Allen C R,Gillespie A R,Han Yuan,et al.Red River and Associated Faults,Yunnan Province,China:Quaternary Geology,Slip Rates,and Seismic Hazard[J].Geological Society of America Bulletin,1984,95(6):686-700
[20]Wang Shuai,Xu Caijun,Wen Yangmao,et al.Slip Model for the 25 November 2016 Mw 6.6 Aketao Earthquake,Western China,Revealed by Sentinel-1and ALOS-2 Observations[J].Remote Sensing,2017,9(4):325,DOI:10.3390/rs9040325
[21]Wang Yiran,Li Youli,Si Supei.The Geometrical Characteristics of Offset Streams and the ShipingJianshui Fault Activity[J].Quaternary Sciences,2015,35(1):100-108(王怡然,李有利,司苏沛.石屏-建水断裂水平错断河流的几何特征与断层活动性研究[J].第四纪研究,2015,35(1):100-108)
[22]Jiang Zaisen,Liu Jingnan.The Method in Establishing Strain Field Velocity Field of Crustal Movement Using Least Squares Collection[J].Chinese J Geophys,2010,53(5):1 109-1 117(江在森,刘经南.应用最小二乘配置建立地壳运动速度场与应变场的方法[J].地球物理学报,2010,53(5):1 109-1 117)