Japan earthquake and tsunami?

The quakes in 2004 and 2011 were very similar. Look up 'subduction zones', and how they can trigger tsunamis. The tsunami killed many more people because the Indian Ocean is smaller than the Pacific, and there is no organized tsunami warning system there. The waves hit the heavily populated areas of Indonesia, Malaysia, Myanmar, Bangladesh, India and Sri Lanka before the news could get through the rather weak communications network. Whereas Hawaii and the west coast of North America was notified of the tsunami in 2011 hours before it struck, so they had plenty of time to prepare, and the very size of the ocean helped mitigate the force of the waves.