地震勘探組合法之研究（一）

假定随机干扰是对位置平稳的随机变量,利用固定瞬间多道记录统计分析方法,讨论了组合地震法的统计效应及其效益,提出了在线性等距组合形式中组內间距选择以适应信杂比最大的条件,并讨论了选用组合形式和组內间距的方法。

STATISTICAL MULTIPLE SEISMIC DETECTION THEORY （Ⅰ）

In seismic detection, the principal sources of random noises are microseisms, instantaneous fluctuations of apparatus and extraneous disturbances caused by shooting. The former two sources are independent of shooting. They could be measured easily, and their auto- and cross correlation functions are useful for designing the array arrangement and the prediction filter to improve the signal-to-noise ratios of the first arrivals in the records. But the latter one, that is, the extraneous wave caused by the shot, travels to the detecting stations together with effective waves. The waveforms and times of arrivals of the signals differ from place to place and are usually unknown. Therefore, the ordinary time series analysis method seems somewhat complicated owing to the unstationary nature of the phenomenon. The present study is concerned with a statistical method for the moment at which a closely spaced array that makes effective wave recording at the same time in all the detectors in an array. The spatial correlation function that is independent of the signals can be evaluated. Based on the space correlogram obtained in some regions of China, the problem of how far the signal-to-noise ratio can be improved by multiple detection is discussed. It is shown that the improvement of signal-to-noise ratio depends not merely on the number of seismometers in a single group, but also on distances between them, and on the space correlation function. A procedure which gives optimum distance between seismometers in a group is described and it can easily be used in seismic field operation.