Strong Motion in Absorbing Nonlinear Medium and Problems of Their Registration

Abstract

In the paper some physical phenomena in natural soils are considered, provided by intensive seismic excitation. On the basis of regressive analysis of Racha earthquake instrumental data and so-called “dimensionality method”, the new parameters, which are tightly connected with absorbing indexes and non-linearity of natural soils have been obtained. The consideration of corresponding correlation links has shown that in epicentral zone of earthquake (30–40 km) the absorption of seismic energy in soft soil is inversely proportional to earthquake magnitude and not significantly depends on acceleration. In rocks the absorption is directly proportional to the acceleration and slightly depends on magnitude. This fact explains considerably the difference degree of buildings’ and constructions’ damage on soft and rock soils.

It was detected the degrees of non-linearity and non-elasticity of soils. Also, it was considered the usage of offered parameters during solving of practical issues of seismic microzonation.

It was shown the uncertainty of differentiation of strong and weak motions. The properties of strong motion is being analyzed, based on corresponding behavior of geomaterial at linear-elastic, nonlinear-elastic, non-elastic deformation.

Partially, it was obtained the empirical quantity for account of intensity level of seismic impact. Following leads to a conclusion about necessity of registration strong motion not only in maximum narrow band of spectrum, but also in wide frequency band of spectrum.