PROJECT TITLE : Interdisciplinary study on the mitigation of NaTech risks in a complex world: learning from Japan experience applying ERRA NaTech, iNTeg-Risk project KEYWORDS : Tsunami ; Domino effect ; Collecting data ; Risk analysis ; Mechanical behaviour of equipments; Equipments reliability ; Warning systems ; Land use planning ; Supply chain ; Economic impact ; SUMMARY : The great earthquake that occurred on March 11th in Japan, is one of the three most powerful earthquakes in the world overall since modern record-keeping began in 1900. The earthquake triggered a destructive tsunami that hit the Pacific Coast of Japan, especially the Tohoku region. This event showed that combination between natural and technological hazards within industrial plants could have disastrous consequences on installations containing hazardous substances, electrical systems, etc. Taking into account the climate change and growing urbanisation on areas prone to natural hazards, the likelihood of natural disasters will increase with a higher exposure of the population. As a consequence, technological accidents triggered by natural disasters (NaTech accidents) pose an enormous challenge to the stakeholders of industrial sector. An answer to this emerging risk has been provided in the framework of iNTeg-Risk, with the development of a specific risk analysis tool ERRA NaTech. This methodology, based on assumptions and simplifications from multi-disciplinary expertises, aims to define measures to prevent Natech accidents within industrial areas. The project presented below, consists in applying the methodology ERRA NaTech in the context of the great Tohoku earthquake. The implementation of methodologies, to define risk prevention measures, requires learning lessons from the feedback of natural disasters. Thus, this disaster in Japan is an opportunity to develop our currents methodology, in particular to tsunami hazard. Such a project involves generating new methods in various engineering fields: risk analysis, structural resistance, uncertainties, and reliability. The earthquake in Japan has proved that engineering tools had to be completed by a policy approach. For instance, the experience has revealed that implementation of emergency measures dedicated to tsunami within industrial sites is an efficient mean to prevent equipment failure and domino effects. Finally, the Japan disaster has shown the vulnerability of the economic system trough the supply chain disruption and its consequences on non impacted areas. Higher dependency on vulnerable networks (telecom, lifelines, and installations) is the main explanation to this failure. The complexity of a multi-disciplinary analysis as Natech risk assessment requires regrouping various expertises. That’s the reason why partners involved in this project have a complementary approach starting from engineering expertise to social sciences.