Deterministic seismic hazard analysis for the city of Corinth-central Greece

Theodoros M. Tsapanos*1, George Ch. Koravos1, Vasiliki Zygouri2, Michael T. Tsapanos3, Anna N. Kortsari4, Andrzej Kijko5 and Eleni E. Kalogirou6

1 Aristotle University of Thessaloniki , School of Geology , Geophysical Lab., 54124 Thessaloniki , Greece

2 University of Patras, Department of Geology, Marine Geology and Geodynamics, 26500 Patras , Greece

3 D. Mitropoulou 20, 54644 Thessaloniki, Greece

4 Th. Sofouli str 62, 54606 Thessaloniki , Greece

5 Aon Benfield Natural Hazard Centre, University of Pretoria , Republic of South Africa

6 T. Oikonomidi 88, 55131 Thessaloniki, Greece

(*tsapanos@geo.auth.gr)

(Received 14 December 2010; accepted 17 January 2011)

Abstract:  Deterministic seismic hazard analysis was performed for the city of Corinth. The city of Corinth has been chosen due to its seismic history. The city was destroyed in 1858 by an earthquake of magnitude MW=6.5. The city was rebuilt a few kilometers away, only to be destroyed again during the devastating event of magnitude MW=6.3 in 1928. We examined the seismic history of Corinth by taking into account all the earthquakes that occurred within distances of 30 and 50 km. The largest earthquake occurrence was within a radius of 30 km during the instrumental period (1981) and had a magnitude of MW=6.7. For the radius of 50 km, two great events of magnitude MW=7.0 occurred during the historical epoch (551 A.D. and 1402). In all calculations, the Peak Ground Acceleration (PGA) attenuation equation for shallow, crustal earthquakes in Greece has been applied. The attenuation equation incorporates information on soil conditions (rock, alluvium and intermediate). The examined city is a coastal site located mainly on alluvium type soil. The destructions of both, the old (1858) and the new (1928) city, happened because the epicenters of these earthquakes were very close, approximately 3 km and 5 km, respectively, from the centres of the cities. The corresponding PGA values generated by these earthquakes were respectively estimated as 0.32g and 0.31g. Maximum PGA values associated with “design earthquakes” were also evaluated by applying a deterministic procedure.