EXPECTED SEISMIC INTENSITY ASSESSMENT TAKING INTO ACCOUNT LOCAL TOPOGRAPHY SITE EFFECT

Abstract

The analysis of seismic codes of different countries shows accounting of seismic properties of
soils caused mainly by their physical and mechanical properties but effect of the topography on site effect is not
even considered. Exception is the Building Codes of France. The paper presents the results of experimental
investigations of the influence of topographic features on the formation of the effect of strong earthquakes.
Examples of amplification of seismic effect due to relief features are shown in the form of field, laboratory and
numerical (mathematical modelling) investigations. It is defined that not only slope angle but also height of
observation point significantly influences on site effect. It is shown that the intensity of the earthquake in
mountainous areas is determined not only by the slope angle value, but also the specific location of the site in the
hierarchy of the rock massif. Obtained instrumental data analysis showed that the influence of the relief on the
seismic effect of the earthquakes can be most completely accounted by the parameter R, that is the product of the
slope angle and the height. It has been defined that the intensity increment can be changed regardless of the
constituent rock types from 0 to 1.5 points. It is found that the vibration amplitude varies considerably with the
relief and this dependence is different for the displacements, velocities and accelerations.