Size and Return Periods of Extreme Disasters

Extreme disasters occur rarely and altogether occasionally, and therefore, the determination of maximum possible size or maximum expected size of natural and other disasters is important for the safety management and for the insurance domain, and considerable attention is paid to it. Systematic methodology development has been supported by professional papers since 70s of the last century or so. At present, the extreme value methods based on the great numbers of law, fuzzy sets etc. are used. The example shows the high differences in the extreme values existing in the application of old concepts and new methods. By use of the extreme value methods, it is also possible to calculate the return period of extreme disasters. The example showing return periods for different disaster sizes is given.