The 1999 Athens earthquake, registering a moment magnitude of 6.0, occurred on September 7 at 2:56:50 pm local time and lasted approximately 15 seconds in Ano Liosia. The tremor was epicentered approximately 17 km to the northwest of the city center, in a sparsely populated area between the working-class town of Acharnes and the Mount Parnitha National Park. This proximity to the Athens Metropolitan Area resulted in widespread structural damage, mainly to the nearby towns of Ano Liossia, Acharnes, Fyli and Thrakomakedones as well as to the northern Athenian suburbs of Kifissia, Metamorfosi, Kamatero and Nea Philadelphia. More than 100 buildings (including three major factories) across those areas collapsed trapping scores of victims under their rubble while dozens more were severely damaged. Overall, 143 people lost their lives and more than 2,000 were treated for injuries in what eventually became Greece's deadliest natural disaster in almost half a century. This event took Greek seismologists by surprise as it came from a previously unknown fault, originating in an area that was for a long time considered of a particularly low seismicity.