NEWS

‘No more non-seismic areas’

The Ionian Islands (apart from Corfu) and part of the prefecture of Aitoloakarnania have always been the most seismically active areas in Greece, a fact now recorded in the country’s new earthquake protection map presented in mid-July and which comes into effect on January 1, 2004. The prefectures of Lefkada, Zakynthos, Cephalonia and the municipalities of Alyzia and Kekropia in Aitoloakarnania are included in the zone of high seismic risk (denoted as 0.3g in the earthquake magnitude-acceleration scale applied in building construction). Corfu and prefectures in mainland Greece bordering on the Ionian Sea are in the middle-range zone (0.24g), including areas where Thursday’s quake was felt, such as Preveza, Arta and Messolonghi. Accelerations recorded on the Seismic Risk Map are taken into consideration by engineers when choosing the metal framework for each building under construction. Obviously buildings in high-risk areas require more fortification than those in low-risk areas. The new map does away with the illusion of «earthquake-free» areas in Greece. The low seismic risk zone (0.12g) has been abolished and areas once characterized as almost «danger free» have been included in the next zone up (0.16g). Others have been moved up from zone 0.16g to 0.24g, as a result of earthquakes in the last 15 years. These include Attica, struck by a major quake in 1999, and greater Thessaloniki. The new map divides the country into three zones of seismic risk (0.16, 0.24 and 0.36g). In practical terms, seismologists say that an area’s inclusion in one of the three zones means a difference of 33-50 percent in seismic activity. The seismic risk of the second zone is up to 50-percent higher than in the first zone. In other words, Lefkada (0.36g) is twice as likely to experience a quake as is an Aegean island in the lowest (first) zone of 0.16g.