On 17 August 1999, an earthquake in northwestern Turkey killed around 17,000 people and left more than 250,000 people homeless. The shock had a moment magnitude of 7.6 and a maximum Mercalli intensity of IX (Violent). The event lasted for 37 seconds, severely damaging the city of İzmit.
The earthquake occurred along the western portion of the North Anatolian Fault Zone (NAFZ). The Anatolian Plate, which consists primarily of Turkey, is being pushed west about 2–2.5:cm (0.8–1.0:in) a year, as it is squeezed between the Eurasian Plate to the north and the Arabian Plate to the south. Major earthquakes in Turkey result mainly from slip along the NAFZ or the East Anatolian Fault.
The Izmit earthquake had a rupture length of 150 kilometers (93:mi) extending from the city of Düzce all the way into the Sea of Marmara along the Gulf of İzmit. Offsets along the rupture were as large as 5.7 meters (18.7:ft).
From the timing of P-wave and S-wave arrivals at seismometers there is strong evidence that the rupture propagated eastwards from the epicentre at speeds in excess of the S-wave velocity, making this a supershear earthquake.
DamageSee also: Earthquake engineering
Destruction in Istanbul was concentrated in the Avcılar district to the west of the city. Avcılar was built on relatively weak ground mainly composed of poorly consolidated Cenozoic sedimentary rocks, which makes this district vulnerable to any earthquake.Damage from the Izmit earthquake
The earthquake was heavily felt in this industrialized and densely populated urban area of the country, including oil refineries, several automotive plants, and the Turkish navy headquarters and arsenal in Gölcük, increasing the severity of the loss of life and property. The earthquake also caused considerable damage in Istanbul, about 70 kilometres (43:mi) away from the earthquake's epicenter....read more