Five years ago on March 11, Japan experienced a 9.0 magnitude "undersea megathrust earthquake," a common type of earthquake that occurs at convergent tectonic plate boundaries, where the plates collide as they are shifting over one-another.
The resulting tsunamis caused nuclear accidents, the biggest of which were level 7 meltdowns at the Fukishima Nuclear Power Plant. The reactors exploded due to hydrogen gas that had built up within the containment building after the cooling systems had failed. An alarming number of 15,894 deaths were counted, 92.5% of which would have died by drowning, due to the unanticipated size of the tsunami waves. The damage by surging water was far more destructive than the actual quake.