EVALUATION OF SITE EFFECTS USING STRONG MOTION KIKNET DATA

Abstract

The level of safety of building during an earthquake depends on various factors like subsurface geology, topography, subsoil condition, building morphology. And overall intensity of earthquake in any region depends on damage in the region. The damage can happen even due to minor earthquake because of the fact that study of subsurface soil is not done prior to the creation of the building. The match of frequency of the structure with the predominant frequency of the soil column beneath the structure lead to the phenomenon of resonance and this condition is disastrous. We have example of Bhuj earthquake in 2001. Each site has a frequency depending upon the geological structure of the region, the type of - soil present, and the thickness of the soil layers and also on the ground water level. Also the manmade structures like buildings and mega-structure like dam, bridges, flyovers etc have their own frequencydepending upon the size, shape, type of material used. The predominant frequency of the soil column is the frequency at which, during an earthquake, the ground motion is likely to increase the amplitude. This may cause more damage in the region.