Western Turkey Seismic History
During the last two millennia, the Gulf of Izmit has been the site of several large and damaging earthquakes:
29: (Nov.24) An earthquake damaged Izmit
69: Nicomedia (Izmit) was destroyed by an earthquake
121: Nicomedia (Izmit) was completely destroyed by an earthquake.
128: Nicomedia (Izmit) was destroyed by an earthquake.
269: Nicomedia (Izmit) and the region up to Daciviza (Gebze) were ruined by an earthquake.
362: (Dec.2) Nicomedia (Izmit) was totally destroyed by an earthquake.
446: (Jan.26) Damaging earthquake at Gulf of Izmit
478: (Sep.25) Helenopolis (Karamürsel) and Nicomedia (Izmit) were totally destroyed with great loss of life.
554: (Aug.16) A destructive earthquake caused the collapse of the best part of Nicomedia (Izmit).
740: (Oct.26) Nicomedia (Izmit), Praenetos (Karamürsel) and Nicaea (Iznik) were damaged by an earthquake.
989: (Oct.25) An earthquake in eastern Sea of Marmara caused heavy damage in Nicomedia (Izmit).
1064: (Sep.23) Region between Istanbul and Izmit were damaged by an earthquake 1567: (Oct.1) An earthquake centered at Sapanca caused damage between Istanbul and Izmit.
1672: (May.25) An earthquake caused damage at Izmit
1719: (May 25) Major earthquake in the east part of Sea of Marmara destroying Yalova, Pazarköy, Karamürsel, Kazìklì, Izmit and Sapanca
1754: (Sep.2) A great earthquake in the Gulf of Izmit. Villages were totally destroyed and about 2000 people killed.
1878: (Apr.19) An earthquake caused damage at Izmit
1894: (Jul.10) A destructive earthquake in the Gulf of Izmit caused extensive damage between Istanbul and Adapazarì. The maximum effects were in the Heybeliada, Yalova and Sapanca region where most villages were totally destroyed with great loss of life.
May 26, 1957 Abant and July 22, 1967 Mudurnu earthquakes.
May 26, 1957 Abant earthquake had a magnitude of Ms=7.0 and a macroseismic epicenter of 40.57 N - 31.00 E. It is associated with a 40 km fault rupture and with a maximum and average offset of respectively 165cm and 55cm. The earthqauke caused total almost destruction within the 40km long narrow valley between Abant Lake (east) and Dokurcun (west), with intensities reaching Io=X (Ambraseys, 1988).
July 22, 1967 Mudurnu earthquake (magnitude: Ms=7.1, macroseismic epicenter: 40.60N-30.80E) took place on the western extension of the fault rupture associated with the 1957 earthquake. The earthquake was associated with a 80km fault rupture. The maxiumum and average fault offsets were respectively 260 cm and 90 cm. The earthquake caused heavy damage in the Mudurnu valley (Io=X) associated with widespread liquefaction of river deposits at distances up to 25km from the fault break (Ambraseys, 1988).
The closest medium size earthquake that have taken place in this century in the vicinity of the site are the June 20, 1943 Hendek and Sept. 18, 1963 Yalova earthquakes. June 20, 1943 Hendek earthquake (magnitude: Ms=6.4, macroseismic epicenter: 40.43N-30.48E) caused heavy damage (Io=VIII) in the region between Adapazari, Hendek, Akyazi and Arifiye and is associated with extensive long-period effects. September 18, 1963 Yalova earthquake (magnitude:Ms=6.4, macroseismic epicenter: 40.65N-29.15E) caused extensive damage (Io=VIII) in the region centered between Çìnarcìk, Armutlu Kaplicasi and Yalova.
Source: Kandilli Observatory and Earthquake Research Institute