NEWS

Tsunami warning system a necessity

Protection from tsunamis must be included in the anti-seismic regulations and a warning system must be installed, advises Professor Vassilis Papazachos. Greek seismologists have documented the areas in Greece most at risk of being struck by tsunamis. The map above was published by Papazachos, P. Hadzidimitriou, V. Karakostas, C. Papaioannou and Professor C. Koukitas from the technical college of Thessaloniki University in the Annales Geophysical journal. The very thick line on the map indicates coastal areas in danger of being struck by a tsunami of 3.5 Ki or above on the six-degree scale used to measure such waves. (The tsunami in Indonesia was six degrees). Those areas include the eastern Cyclades, southern Karpathos, the shores of southwestern Laconia, the southwestern Corinthian Gulf, the Malliakos Gulf, parts of coastal Aitoloacarnania, Preveza and the shores of Albania in the Dyrrachio area. A thick line shows beaches at risk from 2.5-3.5 Ki tsunami waves and a thinner line shows those at risk from 1.5-2.4 Ki tidal waves, while a dotted line shows those that might be hit by a milder wave measuring up to 1.4 Ki. Though Greece is at risk of being hit by tsunamis, there is a long gap between occurrences of such waves. History records the most powerful tsunami in this region in 1200 BC where a six-degree wave caused tremendous damage in Egypt and southern Italy. On July 9, 1956, following a 7.5-Richter earthquake northwest of Santorini, a 25-meter-high wave struck the southwestern coast of Amorgos. «Tsunamis of 6 Ki force occur about once every thousand years, and 5 Ki tsunamis every 70 years or so,» explains Papazachos. Is there any way of protecting areas at risk from tsunamis? According to Papazachos, the great danger in Greece comes from earthquakes themselves, although as he says, «we shouldn’t ignore tsunamis.» He believes a tsunami warning is essential and notes that the requisite knowledge exists, pointing out that the risk map was drafted two decades ago, In areas such as California, says Papazachos, there are provisions for reshaping terrain, such as building barriers in areas under threat.