Seismic risk is raised

Greece has revised the map that divides the country into zones of varying seismic risk, raising several areas to higher risk zones and scrapping the lowest risk zone from the map currently in use. This heightened risk assessment will have a direct effect on the building code and the quality of anti-seismic construction, adding a small extra cost. About 50 percent of all Europe’s seismic activity takes place in Greece. Underlining the perennial problem, an earthquake with a magnitude of 4.8 shook the region of Psachna on the island of Evia at 4.46 p.m. yesterday. This was the sixth moderate quake in the region since June 13, with the strongest one so far registering 4.9 on June 18. Hundreds of buildings in the region 70 kilometers (43 miles) northwest of Athens have been damaged in the past two weeks. The revision to the map that came into effect in 1995 divides the country into three zones of earthquake risk, instead of the current four. The 1995 map was based on data from 1986-89 and the revision reflects the experience of the last few years with the serious earthquakes of Attica (September 1999), Skyros (2001) and Konitsa (1996). Earlier, there were serious quakes at Aigion and Grevena in 1995 and in Patras and Pyrgos in 1994. The changes are aimed at raising awareness of the danger and also to simplify zones, as some provinces are presently divided into three zones. Environment and Public Works Minister Vasso Papandreou presented the new map which was ordered in 2000 and will come into effect on January 1, 2004. The zones are divided according to peak ground accelerations (PGA), which is the basis for determining construction. The 0.12g zone is scrapped, with the lowest level, Zone 1, being defined as PGA above 0.16g. Zone II is above 0.24g and Zone III above 0.36g. The seismic danger from one zone to the higher one increases between 33-50 percent. Scrapping the lowest level means that parts of Attica, such as Marathon, Rafina, Spata, Keratea, Kalyvia, Anavyssos, Saronida and Lavreotiki move up to the new Zone I. Other parts of Attica which were affected more by the 1999 quake, such as Ano Liosia, Ilion, Kamatero, Fyli and Aspropyrgos move up to Zone II. In Thessaloniki, Kallithea and Migdonia move up to Zone II. The Public Works Ministry says building a house in an area moved up to Zone III from Zone II will add 0.5-1 percent to the cost.