Earthquakes are the expression of the continuing evolution of the Earth planet and of the deformation of its crust and occur worldwide; while the largest events (M>7. 5) concentrate on plate boundary areas and active plate interiors, moderate earthquakes may take place, if rarely, in all continental areas and may turn catastrophic in areas with poor building construction practice, as tragically shown by the sequence of earthquakes striking the Caucasus region in recent years (Spitak, Armenia, 1988; Rutbar, W. Iran, 1990; Ratcha, Georgia, 1991; Erzincan, E. Turkey, 1992). Vulnerability to...