An earthquake measuring 6.3 in magnitude has hit New Zealand's South Island, hours after an initial quake killed two people.
The new tremor struck at 13:45 local time (00:45 GMT) at a depth of 10km (6 miles), northeast of Christchurch.
A 7.5-magnitude quake, with the same depth, had hit the same area just after midnight, triggering tsunami warnings.
A large river dammed up by a landslide has now breached its banks sending a "large wall of water" downstream.
Residents around the Clarence River - one of the largest on South Island - were being urged to move immediately to higher ground.
There have been hundreds of strong aftershocks, causing power shortages and cuts in water supply, since the initial quake.
GeoNet, a government-funded project monitoring earthquakes, said the first earthquake was actually two related tremors, and that aftershocks would continue over the next few months.
As the aftershocks keep coming, Kiwis up and down the country are sharing the same emotions.
Exhaustion from a sleepless night, concern for those still cut off from communication, and sadness for the two people who lost their lives. But there is also real relief.
This earthquake was greater in magnitude than 2011's Christchurch tremor, but it didn't bring the same level of devastation.
The cost of rebuilding will be huge - major parts of New Zealand's infrastructure have been twisted and snapped out of shape.
But as is often the case when disaster strikes, New Zealand's people have pulled together, checked on their neighbours and offered each other a safe haven.