Journal of Earth Science & Climatic Change
Open Access

Abstract

Prediction of parameters of seismic, explosive waves on the surface of Earth on different distances from the focus by design methods requires determination of regularities of wave propagation and attenuation in soils. To do so, it is necessary to solve wave problems with the use of certain laws of soil strain. It is known that in soil medium shock waves, originated in the focus of an earthquake or in the center of explosion, in the process of propagation transform into low-frequency longitudinal and transversal seismic waves; that is, a high-frequency component of shock waves is rapidly damping, while low-frequency waves propagate on long distances from the focus. Numeric solutions obtained for one-dimensional non-stationary problems on longitudinal wave propagation in soils (as in elastic, viscous-elastic medium) have shown that in these media transformations of shock waves into low-frequency seismic ones does not occur. In elastic medium the waves propagate without damping, while in linear viscous-elastic ones (standard-linear body) high-frequency waves do not damp. In these media it is impossible to obtain linear proportional dependence between damping coefficient and the frequency of longitudinal waves. An account in the law of soil strain (and not only soil, but in composite threads, flexible interlinkings) of structural changes under strain, in other words, of non-linear properties of soil, leads to transformation of shock waves into continuous longitudinal waves. Numeric solutions to wave problems on propagation of longitudinal waves in linear and non-linear viscous-elastic medium have been considered in the paper. The changes of wave parameters in these media and the regularities of damping on the frequency of longitudinal waves in a wide range have been obtained.

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