RESONANT SITE EFFECTS IN SUBSURFACE SOILS AND ROCKS

Catastrophic effects of earthquakes are often connected with natural resonances, which are wide-spread in seismic fields, because of the layered or block structure of real geological media, the presence of fault zones, waveguides and inclusions. Various types of resonances and resonant excitations of structural inhomogeneities of the medium by storm microseisms, seismic waves of earthquakes and vibrator sources are possible. One of the methods of studying natural resonances is an active experiment with a seismic vibrator. The method allows determining resonant frequencies, the location and size of resonant structures. In this paper, an active experiment with a powerful vibrator source is described, in which resonant oscillations of a layered sedimentary medium are studied