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研制并应用一种新技术来确定三分量地震台阵数据的台阵平均质点运动。这种方法基于多斜率谱法延伸的多重小波,是傅里叶法和台阵处理时域法的混合。质点运动由时域主分量法求出。对集中在多个矩阵中小波的交换信号(每个矩阵一个小波)进行复杂的奇异值分解。利用每个矩阵最大奇异值的特征向量来估算各单独信号间的相位。我们求出各分量问的相对相位来估算台阵的平均质点运动椭圆。由于多重小波的冗余度和用于复平面内单个相位因子的 M 估量,使得运算程序更加稳定。此方法应用于1990年和1991年在加州度尼翁平地三分量台阵实验获得的数据。我们发现 P 波质点运动与纯纵波在各向同性介质中的运动差异很明显,响些方位角异常达40°。方位角变化的质点运动异常与频率有关,通常频率升高时异常大小也增加。在台阵深井孔内153m 和274 m 以下,传感器测量值图案与地表传感器值难以区分。数据与倾斜、横向各向司性介质(向西北倾斜30°,走向为70°的对称面)模型相符。我们认为其结果是3方面的影响叠加造成的:(1)花岗闪长岩基岩沿节理的优势风化弓i起的近地表各向异性。(2)与圣罗莎糜棱岩有关的结构和内在各向异性造成的大尺度各向异性。(3)近地表散射。
A new technique has been developed and applied to determine the average particle motions of three-component seismic array data. This method is based on the multi-slope spectrum of multiple wavelet extension, Fourier method and array processing time domain method of mixing. Particle motions are obtained from the time-domain principal component method. Complex singular value decomposition of the commutation signals (one wavelet per matrix) of the wavelet centered in multiple matrices. The eigenvector of the largest singular value of each matrix is used to estimate the phase between the individual signals. We calculate the relative phase of each component to estimate the average motional elliptical of the array. The computation procedure is more stable due to the redundancy of the multiple wavelet and the M-estimation for the single phase factor in the complex plane. This method was applied to data obtained from a three-element array experiment at the Plains of Dunedin, California, in 1990 and 1991. We found that the movement of P-wave particle motion and that of pure P-wave wave in isotropic medium are obvious, with some azimuthal anomalies up to 40 °. Abnormal changes in the azimuthal motoneurons are frequency dependent, and as a rule the anomalous magnitude increases as the frequency increases. In the deep borehole of the array below 153m and 274m, the sensor measurement pattern and surface sensor values are difficult to distinguish. The data are consistent with the model for sloped and transversely divergent media (symmetric plane tilted 30 ° to the northwest and 70 ° oriented). We think the result is a superposition of three effects: (1) Near-surface anisotropy of the granodiorite bedrock along the dominant weathering bow. (2) Large-scale anisotropy due to the structure and intrinsic anisotropy associated with the Santa Rosa mylonite. (3) near surface scattering.