A heavy earthquake forecast

A powerful earthquake rocked the island of Crete late on Tuesday, causing minor damage but no injuries. The quake, occurring at 11.54 p. m., registered 5.8 on the Richter scale, the Athens Geodynamic Institute said. Thessaloniki University put it at 6.1 Richter. It was felt strongly in Athens, 170 km away, and in Cairo. The fact that it occurred under the seabed at a depth of about 100 kilometers prevented it from causing severe damage. Objects in shops and houses on Crete came crashing down and residents of cities such as Iraklion rushed into the streets in alarm. Officials said that the quake appeared to be an isolated incident, like the 6.6-Richter one that hit Karpathos, east of Crete, on January 22 and which was also at a great depth. Tuesday’s quake was on the inner side of the so-called Greek Arc which starts in the Saronic Gulf outside Athens and stretches southward past the islands of Melos and Santorini before ending at Kos in the eastern Aegean. It is where the African and European plates meet. «The evidence so far is very positive, in my opinion,» said Giorgos Stavrakakis, director of the Athens Observatory. «It is a very good sign that we have not had post-seismic activity,» he said. «But we will have to wait 48 hours before we can draw safer conclusions.» The Greek Arc and two other areas are of particular concern to seismologists. Kathimerini has learned that last October Prof. Vassilis Papazachos of Thessaloniki University and his team sent a confidential report warning of powerful quakes in the midterm to the National Scientific Committee for Evaluating Seismic Dangers. It was discussed and passed on to the Public Works Ministry. In the report, Papazachos stresses that he is not trying to forecast earthquakes, which would have a practical value – such as predicting the day, epicenter and magnitude. The warning, he wrote, was aimed at bolstering anti-seismic preparations. The midterm forecast concerns fears of a 6.8-Richter quake along the southwestern part of the Greek Arc after August 2002. (Most of the forecasts have a variable of 0.5 Richter in terms of magnitude and 18 months in terms of their date.) This would affect Kythera, the eastern Peloponnese, western and central Crete and the western Cyclades. On the eastern part of the same arc, a 6.6-Richter quake and a 6.8-Richter one might occur sometime around February 2003, affecting the Dodecanese islands, Samos, the eastern Cyclades and western and central Crete. On the Northwestern Turkish Arc, a 6.4-Richter quake could come after May 2002 and a 7-Richter one after May 2003. These quakes would affect Turkey and northeastern Aegean islands such as Lesvos, Lemnos and Chios. «The western movement of the Anatolian lithospheric plate puts pressure on the Aegean plate,» the report said. «Therefore, large quakes in the Marmara Sea are usually followed (within a few years) by large quakes on the Greek Arc. The great quake of Nicomedia [Izmit, in August 1999] increases the possibility of large quakes on the Greek Arc this decade.» Also, after February 2003, a 6.7-Richter quake could hit the Ohrid region, where Greece, Albania and the former Yugoslavia meet.