Japan - Earthquake and Tsunami - Episode 3
The magnitude 9 earthquake that hit the coast of Japan in March was the most powerful in the country’s recorded history.
Over 25,000 died, most because of the vast tsunami stirred up in the Pacific.
But Japan is a country with long experience of devastating quakes.
In 1923, 100,000 died in Tokyo following an earthquake and the capital city was hit again eight decades before that.
The whole island of Honshu has been seismically 'turned on' by the stresses generated in March, one expert has told the BBC.
Does that mean more major devastating quakes will follow?
Or is the whole attempt to forecast earthquakes doomed to failure?
Roland Pease reports.