A study on the seismic risk of local buildings

Abstract

Earthquakes originate from a sudden release of elastic energy caused by the rupture of rock in the Earth's interior. The damaging effects of earthquakes are mainly caused by the impact of seismic waves. It is now commonly accepted that wave propagation effects play an important role in earthquake damage. The seismic signal is particularly affected by the sub-surface geology. Considerable amplifications occur if a layer with low seismic velocities overlies material with high seismic velocities. Earthquake ground motion excites the buildings and makes them resonate in correspondence with their natural frequency and damping. A particularly dangerous situation arises if the natural frequency of a structure falls in the frequency range of major seismic propagation. In this case the accelerations measured at the earth's surface.