The Poblem 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, which may strongly shatter large areas. It is now commonly accepted that wave propagation effects play an important role for earthquake damage. The seismic signal is particularly affected by the subsurface 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 corresponding to their natural frequency and damping. A particular dangerous situation arises if the natural frequency of a structure falls in the frequency range with of major seismic radiation. In this case the accelerations within the structure may be several times higher than the ground accelerations measured at the earth's surface.

The solution. It has become possible by now to create significant physical models permitting the creation of scenarios for the simulation of strong ground motion. These synthetic approaches account for the individual characteristics of the sites in cities or at industrial plants as well as the properties of the relevant earthquakes. Mestor recently developed ShakyGround, a software devoted to the estimation of earthquake effects both at single sites and for entire zones. ShakyGround in this context forms a seismological base for the earthquake resistant design of buildings and for seismic zoning aimed at purposes of proper land-use and emergency planning.