A mega- tsunami (7 meters of run up), caused by a major earthquake (Mw = 9, the great Tohoku earthquake, peak ground accelerations > 2.5 m / s ² ), striked at 3:32 pm a petrochemical complex located in an industrial port. 850 employees and 1,100 subcontractors belonging to the various companies have evacuated the site after the first foreshocks occurred at 2:46 pm, once the production units were put in a safe state (flaring of products being processed, shutdown of hazardous materials pipe and utilities like boilers, cracking units… ). The tsunami waves, reaching 4,7 to 8.4 m, flooded at 3:30 pm and then at 4:40 pm some facilities. In the late afternoon, a new phase of plant safety operations were launched as soon as the tsunami’s ebb tide. Some employees were slightly injured during the first foreshocks. Damage are extensive : in addition to the loss of utilities (gas, electricity, water), pipelines are displaced and twisted, their insulation destroyed. Large storage tanks have experienced roof sinking due to sloshing, roads and foundations of some equipments have sunk 8 to 70 cm in the ground under soil liquefaction. The tsunami also destroyed wharfs, flooded utilities buildings, drowned the complex’s seawater pumping station, turned the main navigation channel impassable. A chemical tanker was also ripped from its moorings and, while drifting in the port, damaged more pipes and wharfs. The amount of damage and production loss of the twenty petrochemical companies operating in the complex exceeds 1.5 billion of euros (2011).

The main channel was dredged for more than 4 months, and various petrochemical units were gradually restarted between 1 month and 6 months after the disaster, depending on the severity of the damage.