INFLUENCE OF INHOMOGENEOUS LAYERED MEDIA IN THE UPPER CRUST ON DYNAMICS OF SEISMIC SIGNALS

Abstract

The paper considers the influence of deep and subsurface heterogeneities on the parameters of seismic signals from earthquakes. Evaluation of degree of influence of the above heterogeneities on the calculated parameters of seismic effects is the main goal of the study. To describe behaviour of the geological medium there have been used accelerograms, frequency characteristics and seismic spectra. The DSS data and those obtained by seismic microzoning of the Baikal-Amur Main Line, Zeya Hydroelectric Power Station, Bilibin Nuclear Power Station and Blagoveshchensk heat-and-power plant were employed for construction of the calculated seismic models. A comparison of the computed frequency characteristics with those derived from local earthquake records has been done. It is shown that a differentiated approach is needed for seismic hazard evaluation of the areas and sectors at the stage when the initial seismicity is revealed, which requires taking into account deep heterogeneities. The latter distinguish the seismic signal, to a greater extent, in the course of detailed seismic zonation and microzoning.