A probabilistic seismic hazard assessment for Greece and the surrounding region including site-specific considerations

A probabilistic approach was applied to map the seismic hazard in Greece and the surrounding region. The procedure
 does not require any specification of seismic sources or/and seismic zones and allows for the use of the
 whole seismological record, comprising both historical and instrumental data, available for the region of interest.
 The new seismic hazard map prepared for Greece and its vicinity specifies a 10% probability of exceedance
 of the given Peak Ground Acceleration (PGA) values for shallow seismicity and intermediate soil conditions for
 an exposure time of 50 years. When preparing the map, the new PGA attenuation relation given by Margaris et
 al. (2001) was employed. The new map shows a spatial distribution of the seismic hazard that corresponds well
 with the features of shallow seismicity within the examined region. It depicts the level of seismic hazard in which
 the exceedance of the PGA value of 0.25 g may be expected to occur within limited areas. The highest estimated
 levels of seismic hazard inside the territory of Greece are found in the Northern Sporades Islands, where PGA
 values in excess of 0.50 g are reached at individual sites, and in the Zante Island in Western Greece, where PGA
 values in the range of 0.35 g to 0.40 g are obtained at more numerous localities. High values are also observed
 in the sea between the Karpathos and Rhodes islands, near the Island of Amorgos (Cyclades Archipelago) and
 in the Southwestern Peloponnesus. The levels of seismic hazard at the sites of seven Greek cities (Athens, Jannena,
 Kalamata, Kozani, Larisa, Rhodes and Thessaloniki) were also estimated in terms of probabilities that a
 given PGA value will be exceeded at least once during a time interval of 1, 50 and 100 years at those sites. These
 probabilities were based on the maximum horizontal PGA values obtained by applying the design earthquake
 procedure, and the respective median values obtained were 0.24 g for Athens, 0.28 g for Jannena, 0.30 g for
 Kalamata, 0.21 g for Kozani, 0.24 g for Larisa, 0.43 g for Rhodes and 0.35 g for Thessaloniki. The probabilities
 of exceedance of the estimated maximum possible PGA value were also calculated for the cities to illustrate the
 uncertainty of maximum PGA assessment