Wednesday, February 23, 2011

Massive iceberg shears off New Zealand glacier after quake

Terra Daily via AFP: A 30 million tonne block of ice sheared off a New Zealand glacier just minutes after a violent earthquake devastated the city of Christchurch, officials said Wednesday. The huge iceberg crashed into a lake shortly after the 6.3 magnitude tremor rocked the South Island on Tuesday and created waves up to three metres high for 30 minutes which rocked two sightseeing boats on the lake at the time.

The enormous iceberg -- estimated to weigh 30 to 40 million tonnes -- began ripping off the Tasman Glacier at Aoraki Mount Cook National Park accompanied by a loud noise which sounded like a rifle shot, a local tourism official said. Aoraki Mount Cook Alpine Village tourism manager Denis Callesen said locals had been expecting a major iceberg to drop from the glacier for the past month, but the "curve ball" was that the event was caused by an earthquake.

"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 AFP. "Within about a minute of that happening, the staff at the lake heard from five kilometres away (from the glacier) 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."

The Department of Conservation confirmed that a "large chunk" of the glacier fell into the lake but was unable to say if this was caused by the earthquake, which was only felt lightly around Mt Cook some 150 kilometres (93 miles) from the epicentre. "You could argue whether the earthquake precipitated it or not -- the fact is that the terminal face was about due to carve anyway," area manager Richard McNamara told AFP....

The view across Tasman Lake to the rock-covered Tasman Glacier, New Zealand's longest glacier, with the Minarets (3040 m) visible in the distance. Icebergs float on the lake, and part of the lateral moraine projects into the lake on the left. The scour line left by the glacier in previous centuries marks the hillside to its right. Shot by Avenue, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

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