If this earthquake swarm had occurred on land in a populated area then it would have been one of the most destructive events of all time. Thank God it happened out to sea.

NZ east coast residents were awoken by a 7.3 around 2.30 in the morning. Coastal residents were told to evacuate and seek higher ground.

They were to allowed to return to their homes around 6 am, whereupon a second quake of 7.4 struck to the north, which sent them scurrying again.

Shortly after that, the main course - a massive 8.1 - also to the north east.

That's a serious rearrangement of the furniture.