Historical and Prehistorical Earthquakes in the Caucasus - D. Giardini - Bog

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 disaster is increasing as urbanisation and development occupy more areas that are prone to the effects of significant earthquakes. In order to minimize the loss of life, property damage and social and economic disruption caused by earthquakes, it is essential that reliable estimates of seismic hazard be available to national decision makers and engineers for land use planning and improved building design and construction. While short- and mid-term earthquake prediction may one day be able to reduce significantly the death toll of earthquakes, the environmental effects (collapse of buildings and infrastructures, disruption of the productive chain, human resettlement) can be reduced only through a long-term prevention policy in earthquake-prone areas based on the assessment of seismic hazard and risk, the implementation of safe building construction codes, the increased public awareness on natural disasters, a strategy of land-use planning taking into account the seismic hazard and the occurrence of other natural disasters.