The Christchurch earthquake has triggered 30m tonnes of ice to fall off the Tasman Glacier.

The glacier is 200km (125 miles) away from Christchurch, near the west coast of the South Island, in Aoraki/Mount Cook National Park. 

The ice was dislodged on Tuesday afternoon, just after the earthquake struck. The piece of ice was 1.2km (0.75 mile) long, 300m (330 yards) high and 75m (80 yards) wide.

The ice has broken up into icebergs now floating in the Tasman Lake, one of which is 250m long.

A group of tourists were on a boat in the lake at the time and were thumped by giant waves caused by the ice drop. The tourists were not in danger and were not injured.

Aoraki Mt Cook Alpine Village General Manager Denis Callesen said heavy rainfall recently fell in the area, making the chunk of ice vulnerable.

“The earthquake that we felt here was a swaying motion for about a minute, then it stopped and then it swayed for about another minute,” he told the AFP news agency.

“Within about a minute of that happening, the staff at the lake heard from five kilometres away a sound that sounded like a rifle shot and then over the next two minutes all the events started to unfold.

“I have absolutely no doubt in my mind that the earthquake was the trigger.”

But the Department of Conservation did not believe that the quake caused the ice fall.

“You could argue whether the earthquake precipitated it or not – the fact is that the terminal face was about due to calve anyway,” area manager Richard McNamara told AFP.

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