A Linear Model for the Yield Dependence of Magnitudes Measured by a Seismographic Network

Abstract

Summary The connection between the yields of six underground nuclear explosions in the Pahute Mesa in Nevada and the body and surface wave magnitudes measured at 19 Canadian seismographic stations is described by a simple statistical model. It describes the expected magnitudes as linear functions of the logarithm of the yield and attributes the apparently normally distributed magnitude variations between stations to wave path dependent level differences between the transfer functions from the source area to the stations. The model assigns the same scaling exponent for yield to all stations. The exponent is, however, larger for surface wave magnitudes than for body wave magnitudes. The station residuals are partly attributed to differences, between explosions, in the energy coupling in the source area. The residuals are roughly normally distributed and the stations can be divided into groups with high and low residual variances. Applications of the model to the prediction of station magnitudes from given yields, to the calculation of maximum likelihood estimates of yields from measured station magnitudes and to the identification of underground nuclear explosions by simultaneous measurements of body and surface wave magnitudes are briefly discussed.