Seismic zoning studies in the area of Greece based on the most perceptible earthquake magnitude

Abstract

The Greek seismicity file developed by Makropoulos and Burton (1981) for earthquakes up to 1978 and extended up to 1983 (Makropoulos et al., 1986), is examined in terms of magnitude frequency using Gumbel’s third type asymptotic distribution of extreme values. The forecasting parameters are obtained by subdividing Greek seismicity in a cellular manner. Combination of the Gumbel III earthquake occurrence statistics for each cell with acceleration attenuation law leads to perceptibility curves which give the probability of perceiving specific acceleration levels from each earthquake magnitude up to local upper bound magnitude w. These curves show a peak probability which occurs at similar magnitudes defined as the “most perceptible” earthquake. The range of these “most perceptible” earthquake magnitudes is for an M_s of about 5.3 to 7.2.

The results are presented as contouring maps for two average depths of 10 km and 20 km respectively. The features of the contoured perceptibility maps are compatible with existing hazard maps of Greece based on different approaches. This, coupled with the fact that these values may be used as a criterion for choosing engineering design time histories, shows the usefulness of the method for seismic zoning problems.