影响面波勘探精度的因素探讨
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摘要
分析了影响面波勘探精度的主要因素 ,针对计算面波相速度的精度问题 ,讨论了常用测量台间面波相速度方法的优缺点及其适用范围 ,并提出通过测量台间格林函数进行相位校正 ,以得到两台之间的精确相位。以合成的高频理论地震图作为记录信号 ,并在理论地震图上叠加了 2 0 %的随机噪声 ,利用这些方法分析理论信号 ,数字实验表明 :在相干频率范围内 ,格林函数方法能够精确测量台间相速度 ,而互相关法和窄带通滤波互相关法所得结果较为离散。以此方法对一个排列的实测地震面波信号进行处理 ,最后反演得该测线下面介质的剪切波速度结构
The main factors effecting on exploration precision of surface wave are analyzed in the light of calculation of phase velocity of surface wave; the merits and demetits of common computing methods for phase velocity between stations and their applied range are discussed and calculation of interstation Green's function for correcting phase is put forward to get the precise phase difference between two stations. Some methods, in which synthesized theoretical seismogram of high frequency is taken as record signal and 20% random noise is superimposed on the seismogram, are used to analyze the theoretical seismogram. The digital experiment shows that in the correlating frequency range, Green's function method can measure precisely interstation phase velocity, but the results obtained by correlation and narrow band-pass filtering correlation methods are more dispersed. The Green's function method is used to an array of observed surface wave signals and velocity structure of shear wave beneath the array is obtained.
The main factors effecting on exploration precision of surface wave are analyzed in the light of calculation of phase velocity of surface wave; the merits and demetits of common computing methods for phase velocity between stations and their applied range are discussed and calculation of interstation Green's function for correcting phase is put forward to get the precise phase difference between two stations. Some methods, in which synthesized theoretical seismogram of high frequency is taken as record signal and 20% random noise is superimposed on the seismogram, are used to analyze the theoretical seismogram. The digital experiment shows that in the correlating frequency range, Green's function method can measure precisely interstation phase velocity, but the results obtained by correlation and narrow band-pass filtering correlation methods are more dispersed. The Green's function method is used to an array of observed surface wave signals and velocity structure of shear wave beneath the array is obtained.
引文
〔1〕胡家富 .Rayleigh波勘探中的解释问题探讨 .岩土工程学报 ,1999,2 1(5 ) :5 99～ 6 0 2
〔2〕胡家富 ,段永康 ,胡毅力 .利用多道信号测量短周期面波频散 .地球物理学报 ,1988,41(增刊 ) :2 98～ 30 4
〔3〕杨成林 .瑞雷波勘探 .北京 :地质出版社 ,1993. 96～ 97
〔4〕赵鸿儒 ,郭铁栓 ,徐子君等 .工程多波地震勘探 .北京 :地震出版社 ,1996 . 2 30～ 2 34
〔5〕冯锐 ,周海南 ,姚政生 ,孙克忠 .面波的频散、反演和层析成像 .中国地震 ,1987,3 (1) :15～ 2 7
〔6〕TaylorS .R .andM .N .Toksoz MeasurmentofinterstationphaseandgroupvelocitiesandQusingWienerfiltering Bull Seism Soc Am ,1982 ,72(1) :73～ 91 〔7〕RussellD .R .,R .B .HerrmannandH .J .Hwang Applicationoffrequencyvariablefilterstosurface -waveamplitudeanalysis.Bull Seism Soc Am ,1988,78(1) :339— 35 4
〔8〕HerrmannR .B .andW .C .Wang Acomparisonofsyntheticseismograms Bull Seism Soc Am ,1985 ,75 (1) :41～ 5 6
〔9〕胡家富 ,段永康 ,胡毅力等 .利用Rayleigh波反演浅土层的剪切波速度结构 .地球物理学报 ,1999,42 (3) :393～ 40 0
〔10〕TriboletJ.M ..Anewphaseunwrappingalgorithm .IEEETransactionsonacoustic ,speechandsignalprocessing ,1977,2 5 (2 ) :170～ 177
〔2〕胡家富 ,段永康 ,胡毅力 .利用多道信号测量短周期面波频散 .地球物理学报 ,1988,41(增刊 ) :2 98～ 30 4
〔3〕杨成林 .瑞雷波勘探 .北京 :地质出版社 ,1993. 96～ 97
〔4〕赵鸿儒 ,郭铁栓 ,徐子君等 .工程多波地震勘探 .北京 :地震出版社 ,1996 . 2 30～ 2 34
〔5〕冯锐 ,周海南 ,姚政生 ,孙克忠 .面波的频散、反演和层析成像 .中国地震 ,1987,3 (1) :15～ 2 7
〔6〕TaylorS .R .andM .N .Toksoz MeasurmentofinterstationphaseandgroupvelocitiesandQusingWienerfiltering Bull Seism Soc Am ,1982 ,72(1) :73～ 91 〔7〕RussellD .R .,R .B .HerrmannandH .J .Hwang Applicationoffrequencyvariablefilterstosurface -waveamplitudeanalysis.Bull Seism Soc Am ,1988,78(1) :339— 35 4
〔8〕HerrmannR .B .andW .C .Wang Acomparisonofsyntheticseismograms Bull Seism Soc Am ,1985 ,75 (1) :41～ 5 6
〔9〕胡家富 ,段永康 ,胡毅力等 .利用Rayleigh波反演浅土层的剪切波速度结构 .地球物理学报 ,1999,42 (3) :393～ 40 0
〔10〕TriboletJ.M ..Anewphaseunwrappingalgorithm .IEEETransactionsonacoustic ,speechandsignalprocessing ,1977,2 5 (2 ) :170～ 177
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