MACROSEISMIC EVIDENCE OF SEISMIC EVENTS CAUSED BY INFLUENCE OF GROUND CONDITIONS AND FORMATION OF MAPS OF SEISMIC MICROZONATION

Abstract

Macroseismic evidence of each significant earthquake carries a unique information about its actual impact on the investigated territory. Therefore, the collection and analysis of all available data on the occurrence of seismic events in the study area is important in assessing seismic hazard. The paper shows the manifestation of the strongest earthquake that occurred in modern times - the Racha earthquake on April 29, 1991 in the territory of Ambrolauri city. The increase in the seismic effect due to the influence of ground conditions is shown. The manifestation of a weak earthquake in 2005 in the territory of the city of Vladikavkaz is considered and a comparison is made with the current seismic microzoning map. The use of modern information technologies made it possible, on the basis of manifestations of weak effects, to single out individual areas in which the seismic effect can be caused by individual local features of ground conditions, as well as the spectral features of the impact and building conditions.