THE STRUCTURE OF THE NOISE BACKGROUND OF A SEISMOGRAM II

Abstract

One second samples of two seismogram traces are analyzed statistically. The traces represent the outputs of two geophones at depths 75 and 125 feet which were part of a vertical spread. The first four moments and the first four semi‐invariants and the standard deviation are computed for the first and second halves of a one second sample from each trace. These quantities are used to compute the distribution functions of the amplitudes of the seismogram traces. The resulting curves agree very closely with the distribution functions determined directly from the seismogram trace. The number of zeros per second are computed from a theoretical formula developed by Rice (1945). It is shown that the observed number of zeros per second agrees with the predicted value, but the agreement is limited by the small number of zeros that occur in a one second sample. Some general conclusions regarding the statistical behavior of the noise background of a seismogram are offered.