New techniques for the determination of surface wave phase velocities.
New techniques for the determination of surface wave phase velocities.
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发表时间：
1968-06
影响因子：
3
通讯作者：
S. Bloch;A. L. Hales
中科院分区：
文献类型：
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作者：
S. Bloch;A. L. Hales
许多新技术已经被开发出来，用于从对台站的数字化地震记录中确定相速度。其中一种技术是傅里叶分析时间移步后的两个地震图的和（或差），以对应相速度的步长。当两个地震记录在某一特定时期相同时，总和地震记录的振幅是该时期的最大值。另一种方法是将两个地震图通过以不同周期为中心的窄带通数字滤波器，经过时移后形成滤波后的地震图的交叉积。当两个信号同相时，所得时间序列的平均值为最大值。计算机输出是由相速度和周期的振幅或平均值组成的矩阵。相速度色散由轮廓矩阵确定。利用这些技术，已经为比勒陀利亚、布拉瓦约和温得和克的“万维网标准站”确定了瑞利波的站间相速度。使用叉积的方法是最有效的。
abstract A number of new techniques have been developed for the determination of phase velocities from the digitized seismograms from pairs of stations. One of these techniques is to Fourier analyze the sum (or difference) of the two seismograms after time shifting in steps to correspond to steps in phase velocity. The amplitude of the summed seismogram is a maximum for any particular period when both seismograms are in phase at that period. Another method is to pass both seismograms through a narrow bandpass digital filter centered at various periods and form the cross product of the filtered seismograms, after time shifting. The average of the resultant time series is a maximum when the two signals are in phase. The computer output is a matrix consisting of amplitudes or averages as a function of phase velocity and period. The phase velocity dispersion is determined from the contoured matrix. Using these techniques, interstation phase velocities of Rayleigh waves have been determined for the “World Wide Network Standard Stations” at Pretoria, Bulawayo and Windhoek. The method using cross-products is the most efficient.