The scale of the tsunami hazard from volcanoes that collapse into the sea has been underestimated, according to a new study.
Many people have come to Japan's "wind phone" after losing family in the 2011 tsunami.
A new model illustrates the tsunami that resulted from December's collapse of Anak Krakatau volcano.
How many volcanoes around the world have the potential to collapse and generate tsunamis?
A Japanese high school hit by the 2011 tsunami has re-opened to visitors as a memorial to the disaster.