The problem of seismic potential assessment: Case study of the unexpected earthquake of 7 September 1999 in Athens, Greece
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences. 2002
Received: 10 April 2000
Accepted: 28 September 2001
Published: 18 June 2014
Lessons learned form the disastrous earthquake (M W = 5.9) that hit the metropolitan area of Athens, Greece, on 7 September 1999, are examined particularly as for the seismic potential considered before the earthquake occurrence. A general belief was created in the past decades that the seismic potential in Athens was very low. Fault plane solutions of the 1999 shock indicate that it was associated with a normal fault trending WNW-ESE and dipping to SW. Field geological observations conducted after the event in the Fili neotectonic fault, situated at 15–20 km to the north of Athens, imply that it has possibly been the seismogenic structure of the main rupture, and that it reactivated in very recent geological times. Archaeoseismological observations performed in the ancient Fili Fort, revealed repaired structural damage that was very likely caused by an earthquake occurring in palaeochristianic or Byzantine times. From a new catalogue of historical earthquakes it results that the main events of 1705, 1805 and 1889 could be tentatively located within a distance of ∼30 km from Athens although the little macroseismic information available makes their locations quite uncertain. During the instrumental period of observation, only few small shocks were recorded in the Athens region. It is obvious that should a research effort had been undertaken before the 1999 earthquake, certainly it would be concluded that at least one strong earthquake took place in historical times in the broad region affected in 1999, and that the Fili fault is active and is capable to produce strong shocks in the future. However, such a study was never conducted by the scientific community beforehand.