EVALUATION OF GROUND CONDITIONS AND OCCURRENCE OF LOCAL SITE EFFECT

Abstract

In the study the data on detailed geophysical and geological observations aimed to the assessment of local soil conditions and possibility of local seismic effect occurrence in the territory of Dvin ancient settlement during the earthquakes of 863 and 893 are presented. The studies have been carried out at the sites with the largest macroseismic impact - central block of the town of Dvin and adjacent area of the Cathedral. Analysis of the obtained soil condition data - dynamic characteristics of the natural frequency, local resonance characteristics, shear wave average velocity in upper 30 meters of subsurface stratum (VS30) allowed to conclude that the high intensity of both Dvin earthquakes caused destructions and mass casualties were conditioned by local amplification of seismic vibration (site effect).