Influence of earthquake characteristics on natural frequency and period of soil column for different subsoils in the Chennai region

An earthquake is one of the critical natural disasters that causes a massive impact on life and property in the areas it occurs. From the past earthquake patterns, the increase in the number of earthquakes in southern peninsular India can be observed. The increasing number of earthquakes is one of the critical reasons for shifting Chennai from zone II (least active) to zone III (moderately active) by the Bureau of Indian Standards. The soil column's natural frequency and time period are the key parameters for seismic design and construction. Furthermore, compared to shear wave velocity, the fundamental period is a key parameter for site amplification in the recent trend because it accounts for both stiffness and depth of soil sediments. In order to determine the fundamental frequency and typical site period, an equivalent linear 1-D ground response analysis was performed in the Chennai region using ProSHAKE 2.0 software. A contour map was created using ArcGISPro software for the study area's fundamental and characteristic site periods. The longer the soil column's site period, the greater the amplification and the greater the seismic threat. Finally, buildings with a natural period of 0.6 - 1 s should be avoided in the southeastern region of the study area because of the resonance.