The crisis of a paradigm. A methodological interpretation of Tohoku and Fukushima catastrophe

International audienceThe 2011 Japanese disaster often presented as a 'new Chernobyl' accumulated the effects of earthquake, tsunami and of the subsequent nuclear accident at Fukushima. In the light of this disaster, we review methodological reasons both from geophysical and philosophical perspectives that lead the scientific and technological communities to flawed conclusions, prime cause of the disaster. The origin of the scientific mistake lies in several factors that challenge a dominant paradigm of seismology: the shallower part of the subduction was considered as weak, unable to produce large earthquakes; a complete breakage of the fault up to the sea-floor was excluded. Actually, it appears that such complete rupture of the subduction interface did characterize megathrust ruptures, but also that hazard evaluations and technical implementation were in line with the flawed consensual paradigm. We give a philosophical interpretation to this mistake by weighing the opposition between a prescriptive account and a descriptive account of the dynamics of research. We finally emphasize that imagination, boldness, and openness (especially to alternatives to consensual paradigms) appear as core values for research. Those values may function as both epistemic and ethical standards and are so essential as rigor and precision. Ability to doubt and to consider all uncertainties indeed appears essential when dealing with rare extreme natural hazards that may potentially be catastrophic