An assessment of seismic hazard and risk in the islands of Cephalonia and Ithaca, Greece

The region of the islands of Cephalonia and Ithaca, Western Greece, is characterized by continuous seismic activity and frequent occurrence of large magnitude earthquakes, which have resulted many times in the past in severe structural destruction and large human and economic losses. This work represents an effort to assess seismic hazard and risk in these two islands. Due to the scarcity of seismic data in the region, artificial accelerograms are generated on the basis of the specific barrier model in order to provide estimates of strong ground motion. Peak ground accelerations of the artificial accelerograms are compared with those coming from an empirically derived ground motion prediction model. The response spectra of the artificial accelerograms are compared with the design spectrum of the Greek seismic code and the seismic damage potential of old and new building structures is assessed and found to be high. From the present study it is concluded that there is a need of monitoring continuously the seismic activity in the region. Thus, the establishment of a dense and time continuous strong ground motion recording network is proposed and briefly described.

► The islands of Cephalonia and Ithaca belong to a seismically active region.
► New buildings there can exhibit light to moderate damage.
► Old buildings there can exhibit moderate to heavy damage.
► A network consisting of 28 accelerographs distributed in both islands is proposed.