Catastrophe is sadly never far from the news headlines, with this year's tsunami in Japan and the Chilean earthquake of 2010 continuing to loom large in the memories of millions.In the UK premiere of Doomsday Earth join experts who examine the likelihood of the planet being struck by both a mega-tsunami and a mega-quake.Their findings are not good news. It seems a giant fault line beneath the sea is readying itself for a violent explosion of activity, and the race is on to calculate when rather than if, this 'megathrust' will do its worst.