Tsunamigenic sources in an active European half-graben (Gulf of Corinth, Central Greece)

Abstract

The Gulf of Corinth is an active half-graben dissecting the mainland of Greece along an east west axis. The Gulf is well known for its intense seismic activity and its rapid extension rates. However, published historical catalogues reveal that the Gulf of Corinth is also the site of frequent and relatively destructive tsunami occurrences. This paper presents a comparative study of the potential of probable tsunami sources in the Gulf of Corinth, by referring to published offshore geology data. Coseismic seafloor displacement along offshore faults and submarine mass failures are the active tsunamigenic sources. The paper applies easy to use empirical and semi-empirical equations that estimate the generated tsunami wave height, just over the source area. Building upon the most probable worst-case scenarios for both coseismic fault-displacement and submarine mass failure generated tsunamis, the tsunami potential of its case is explored. A maximum probable 6.7 ( M w) offshore earthquake would produce a rupture on the seafloor surface with a maximum displacement of 0.66 to 1.08 m in height in the Gulf of Corinth. The tsunami which would be generated by the seafloor displacement would have a wave height of the same magnitude as the seafloor displacement. Furthermore, existing evidence of submarine mass failures that took place over the last 3000 years in the eastern part of the Corinth Gulf had and would have the potential of generating tsunamis with a maximum wave height of 1.04 and 4.04 m and maximum wave length of 4.52 and 6.25 km.