Short report on lessons learned from Kocaeli 1999, August 17 high magnitude earthquake

The Kocaeli earthquake is one of the most destructive recent EQ to strike Turkey. It occurred at 3.02 am (local time) on August 17, 1999 a time when most residents were asleep. Its magnitude was 7.4 (moment scale). Its focal depth was 17 km. A second event (Mw = 7.1) took place on November 12, 1999, in the east part of the first event faulting, increasing the damages in this area. The authors of this report were members of the French post-earthquake field reconnaissance team after of the Kocaeli earthquake of August 17, 1999. Kocaeli earthquake has killed about 20 to 30 thousands people and damaged a large number of industrial facilities around the Izmit gulf which concentrate 40 % of industrial capacity of Turkey. Conclusions of this report concern surface faulting, ground motion, site effects, building seismic design and retrofit, electrical networks and buried piping, and behaviour of industrial facilities. These conclusions could be applied in nuclear design and safety: The evidence of a potentially active fault must be taken into account. Building design should follow adequate construction codes with a specific care on construction detailing and relevant control procedures. Site effects on soft soils sites should be evaluated and taken into account in the design. A specific effort should be made to improve the prediction methods. The Kocaeli EQ revealed many instances of typical already well known failure modes of industrial equipment which should be avoided by appropriate design rules. Not only the main structures and equipment should be seismically designed. Seismic safety has to be considered as a whole, involving essential support systems, and non-safety system the failure of which would impact the functionality of safety systems or equipment ('seismic interaction' concern). Transmission networks and underground lifelines were unexpectedly largely damaged during Kocaeli earthquake. This should be addressed correctly to ensure the efficiency of immediate post-earthquake reactions