利用带倾角断层形变公式研究川滇块体东边界断裂带形变特征
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摘要
在经典的走滑位移公式的基础上进行改进,引入断层倾角信息,使其反映了走滑断层倾角对地表形变的影响。由于断层倾角的存在使得震间位移曲线的中心是以断层面闭锁-滑动分界在地表的投影为中心,并且此处形变变化最大;公式中的倾角项表示拟合的断层倾角,体现了断层出露地表处与断层闭锁-滑动分界的整体偏移,其值往往小于近地表倾角测量值。以改进的公式作为断层剖面分析的拟合公式,应用于汶川地震前后川滇块体东边界主要走滑断裂形变特征的剖面分析研究中,得到的拟合结果与其他方法得到的结果具有较好的一致性。改进公式比原公式更客观地反映了断层的形变状态,但由于针对单条断层的剖面拟合受多种因素的影响,拟合结果需结合实际情况作进一步分析。
Fault dip angle is introduced to reflect the impact of surface displacement of strike-slip dip angle based on classic strike-slip displacement formula.Due to the dip angle of the fault,surface projection is the interface between locking and sliding motion on the fault,where deformation varies greatly.The dip term in the formula represents the fitting dip angle,which represents the overall offset of the surface and the locking-sliding boundary on the fault,and its value is often smaller than the near-surface measurement of dip angle.It was applied in the profile analysis of the main strike-slip fault deformation characteristics of the eastern boundary of the Sichuan-Yunnan block before and after the Wenchuan earthquake by using the improved formula as the fitting formula of the fault profile analysis.The fitting results obtained are consistent with those obtained by other methods.The improved formula reflects the deformation of the fault more objectively than the original one.Because the profile analysis for a single fault is affected by many factors,the fitting results have to be further analyzed in actual situations.
Fault dip angle is introduced to reflect the impact of surface displacement of strike-slip dip angle based on classic strike-slip displacement formula.Due to the dip angle of the fault,surface projection is the interface between locking and sliding motion on the fault,where deformation varies greatly.The dip term in the formula represents the fitting dip angle,which represents the overall offset of the surface and the locking-sliding boundary on the fault,and its value is often smaller than the near-surface measurement of dip angle.It was applied in the profile analysis of the main strike-slip fault deformation characteristics of the eastern boundary of the Sichuan-Yunnan block before and after the Wenchuan earthquake by using the improved formula as the fitting formula of the fault profile analysis.The fitting results obtained are consistent with those obtained by other methods.The improved formula reflects the deformation of the fault more objectively than the original one.Because the profile analysis for a single fault is affected by many factors,the fitting results have to be further analyzed in actual situations.
引文
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[8] Savage J C,Burford R O.Geodetic Determination of Relative Plate Motion in Central California[J].Journal of Geophysical Research,Part B:Solid Earth,1973,78(5):832-845
[9] Xiang Hongfa,Guo Shunmin,Xu Xiwei,et al.Active Block Division and Present-Day Motion Features of the South Region of Sichuan-Yunnan Province[J].Seismology and Geology,2000,22(2):253-264(向宏发,虢顺民,徐锡伟,等.川滇南部地区活动地块划分与现今运动特征初析[J].地震地质,2000,22(2):253-264)
[10]Xie Furen,Su Gang,Cui Xiaofeng,et al.Modern Tectonic Stress Field in Southwest Yunnan,China[J].Acta Seismologica Sinica,2001,23(1):17-23(谢富仁,苏刚,崔效锋,等.滇西南地区现代构造应力场分析[J].地震学报,2001,23(1):17-23)
[11]Hong Hanjing,Yu Yong,Tao Wei,et al.Dynamic Analysis of Continental Meizoseismal Region in China[J].Seismology and Geology,2003,25(1):11-22(洪汉净,于泳,陶玮,等.中国大陆强震区的形成及其动力学分析[J].地震地质,2003,25(1):11-22)
[12]Xu Xiwei,Cheng Guoliang,Yu Guihua,et al.Tectonic and Paleomagnetic Evidence for the Clockwise Rotation of the Sichuan-Yunnan Rhombic Block[J].Seismology and Geology,2003,25(1):61-70(徐锡伟,程国良,于贵华,等.川滇菱形块体顺时针转动的构造学与古地磁学证据[J].地震地质,2003,25(1):61-70)
[13]Cheng Wanzheng,Diao Guiling,LüYipei,et al.Focal Mechanisms,Displacement Rate and Mode of Motion of the Sichuan-Yunnan Block[J].Seismology and Geology,2003,25(1):71-87(程万正,刁桂苓,吕弋培,等.川滇地块的震源力学机制、运动速率和活动方式[J].地震地质,2003,25(1):71-87)
[14]Yi Guixi,Wen Xueze,Su Youjin.Study on the Potential Strong-Earthquake Risk for the Eastern Boundary of the Sichuan-Yunnan Active FaultedBlock,China[J].Chinese Journal of Geophysics,2008,51(6):1 719-1 725(易桂喜,闻学泽,苏有锦.川滇活动地块东边界强震危险性研究[J].地球物理学报,2008,51(6):1 719-1 725)
[15]Zhang Xi,Cui Duxin,Wang Wenping,et al.Using GPS Data to Analyze Horizontal Movement and Strain Accumulation in Sichuan-Yunnan and Its Vicinity Before and After the Wenchuan Earthquake[J].Journal of Seismological Research,2008,31(S1):464-470(张希,崔笃信,王文萍,等.利用GPS资料分析汶川地震前后川滇及其邻区水平运动及应变积累[J].地震研究,2008,31(S1):464-470)
[16]Zhao Jing,Jiang Zaisen,Niu Anfu,et al.Study on Dynamic Characteristics of Fault Locking and Fault Slip Deficit in the Eastern Boundary of the SichuanYunnan Rhombic Block[J].Chinese Journal of Geophysics,2015,58(3):872-885(赵静,江在森,牛安福,等.川滇菱形块体东边界断层闭锁程度与滑动亏损动态特征研究[J].地球物理学报,2015,58(3):872-885)
[17]Wen Xueze.Character of Rupture Segmentation of theXianshuihe-Anninghe-ZemuheFaultZone,Western Sichuan[J].Seismology and Geology,2000,22(3):239-249(闻学泽.四川西部鲜水河-安宁河-则木河断裂带的地震破裂分段特征[J].地震地质,2000,22(3):239-249)
[2] Zhang Peizhen,Xu Xiwei,Wen Xueze,et al.Slip Rates and Recurrence Intervals of the Longmen Shan Active Fault Zone and Tectonic Implications for the Mechanism of the May 12Wenchuan Earthquake,2008,Sichuan,China[J].Chinese Journal of Geophysics,2008,51(4):1 066-1 073(张培震,徐锡伟,闻学泽,等.2008年汶川8.0级地震发震断裂的滑动速率、复发周期和构造成因[J].地球物理学报,2008,51(4):1 066-1 073)
[3] Jiang Zaisen,Fang Ying,Wu Yanqiang,et al.The Dynamic Process of Regional Crustal Movement and Deformation Before Wenchuan Ms 8.0Earthquake[J].Chinese Journal of Geophysics,2009,52(2):505-518(江在森,方颖,武艳强,等.汶川8.0级地震前区域地壳运动与变形动态过程[J].地球物理学报,2009,52(2):505-518)
[4]Wu Yanqiang,Jiang Zaisen,Yang Guohua,et al.Deformation Characteristics of North Section of North-South Seismic Zone in Recent Period[J].Geomatics and Information Science of Wuhan University,2012,37(9):1 045-1 048(武艳强,江在森,杨国华,等.南北地震带北段近期地壳变形特征研究[J].武汉大学学报·信息科学版,2012,37(9):1 045-1 048)
[5] Paul S.Earthquake and Volcano Deformation[M].Princeton:Princeton University Press,2010
[6] Wei Wenxin,Jiang Zaisen,Wu Yanqiang,et al.Motion Characteristics of Major Faults in East Boundary of Sichuan-Yunnan Block Obtained with GPS Data[J].Geomatics and Information Science of Wuhan University,2012,37(9):1 041-1 044(魏文薪,江在森,武艳强,等.利用GPS数据研究川滇块体东边界主要断裂带运动特性[J].武汉大学学报·信息科学版,2012,37(9):1 041-1 044)
[7] Zou Zhenyu,Jiang Zaisen,Wu Yanqiang,et al.Improvements for the Strike/Dip-Slip Displacement Theory Formula of General Dip Fault[J].Journal of Geodesy and Geodynamics,2015,35(3):460-463(邹镇宇,江在森,武艳强,等.针对一般倾角的走滑/倾滑位移理论公式的改进[J].大地测量与地球动力学,2015,35(3):460-463)
[8] Savage J C,Burford R O.Geodetic Determination of Relative Plate Motion in Central California[J].Journal of Geophysical Research,Part B:Solid Earth,1973,78(5):832-845
[9] Xiang Hongfa,Guo Shunmin,Xu Xiwei,et al.Active Block Division and Present-Day Motion Features of the South Region of Sichuan-Yunnan Province[J].Seismology and Geology,2000,22(2):253-264(向宏发,虢顺民,徐锡伟,等.川滇南部地区活动地块划分与现今运动特征初析[J].地震地质,2000,22(2):253-264)
[10]Xie Furen,Su Gang,Cui Xiaofeng,et al.Modern Tectonic Stress Field in Southwest Yunnan,China[J].Acta Seismologica Sinica,2001,23(1):17-23(谢富仁,苏刚,崔效锋,等.滇西南地区现代构造应力场分析[J].地震学报,2001,23(1):17-23)
[11]Hong Hanjing,Yu Yong,Tao Wei,et al.Dynamic Analysis of Continental Meizoseismal Region in China[J].Seismology and Geology,2003,25(1):11-22(洪汉净,于泳,陶玮,等.中国大陆强震区的形成及其动力学分析[J].地震地质,2003,25(1):11-22)
[12]Xu Xiwei,Cheng Guoliang,Yu Guihua,et al.Tectonic and Paleomagnetic Evidence for the Clockwise Rotation of the Sichuan-Yunnan Rhombic Block[J].Seismology and Geology,2003,25(1):61-70(徐锡伟,程国良,于贵华,等.川滇菱形块体顺时针转动的构造学与古地磁学证据[J].地震地质,2003,25(1):61-70)
[13]Cheng Wanzheng,Diao Guiling,LüYipei,et al.Focal Mechanisms,Displacement Rate and Mode of Motion of the Sichuan-Yunnan Block[J].Seismology and Geology,2003,25(1):71-87(程万正,刁桂苓,吕弋培,等.川滇地块的震源力学机制、运动速率和活动方式[J].地震地质,2003,25(1):71-87)
[14]Yi Guixi,Wen Xueze,Su Youjin.Study on the Potential Strong-Earthquake Risk for the Eastern Boundary of the Sichuan-Yunnan Active FaultedBlock,China[J].Chinese Journal of Geophysics,2008,51(6):1 719-1 725(易桂喜,闻学泽,苏有锦.川滇活动地块东边界强震危险性研究[J].地球物理学报,2008,51(6):1 719-1 725)
[15]Zhang Xi,Cui Duxin,Wang Wenping,et al.Using GPS Data to Analyze Horizontal Movement and Strain Accumulation in Sichuan-Yunnan and Its Vicinity Before and After the Wenchuan Earthquake[J].Journal of Seismological Research,2008,31(S1):464-470(张希,崔笃信,王文萍,等.利用GPS资料分析汶川地震前后川滇及其邻区水平运动及应变积累[J].地震研究,2008,31(S1):464-470)
[16]Zhao Jing,Jiang Zaisen,Niu Anfu,et al.Study on Dynamic Characteristics of Fault Locking and Fault Slip Deficit in the Eastern Boundary of the SichuanYunnan Rhombic Block[J].Chinese Journal of Geophysics,2015,58(3):872-885(赵静,江在森,牛安福,等.川滇菱形块体东边界断层闭锁程度与滑动亏损动态特征研究[J].地球物理学报,2015,58(3):872-885)
[17]Wen Xueze.Character of Rupture Segmentation of theXianshuihe-Anninghe-ZemuheFaultZone,Western Sichuan[J].Seismology and Geology,2000,22(3):239-249(闻学泽.四川西部鲜水河-安宁河-则木河断裂带的地震破裂分段特征[J].地震地质,2000,22(3):239-249)