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New Zealand active volcano shaken by small quake, triggering mud flow alert

New Zealand active volcano shaken by small quake, triggering mud flow alert

A small earthquake inside the Mount Ruapehu volcano in New Zealand triggered a landslide alert, though no slide or flood of water from the crater lake occurred, scientists said Thursday.
Scientists said they were trying to determine whether the alert was set off by a small eruption generating a wave that rippled across the lake after the quake.
A huge mud and water flow from the central North Island volcano's crater lake killed 151 people in 1953.
"What triggered this off last night was a small volcanic earthquake of magnitude 3 ... the size that generates an eruption at Ruapehu," senior vulcanologist Brad Scott said.
"So we may or may not have had a small eruption that's thrown out a bit of lake water, that triggered off the system," he told National Radio.
Geological agency GNS Science would try to fly an airplane over Mt. Ruapehu on Thursday in a bid to determine what happened, said duty vulcanologist Steve Sherburn.
It was also possible scientists might not find out what caused the alert, he said.
During the 1996 eruption millions of tones (tons) of ash were tossed over nearby farmland and rocks the size of large cars blasted out of the crater. No major mud flow had occurred at that time.
On Dec. 24, 1953, a huge mud and water flow from the crater washed out a nearby rail line, plunging a laden express train into a nearby river, killing 151 passengers and crew.
The government two years ago decided not to try to prevent a massive water and mud slide that is expected to burst out of the crater lake by late 2007 _ instead focusing on ways to warn residents once a lahar, or mud flow, is under way.
A lahar is expected to occur when a natural dam of volcanic ash around the lake collapses, releasing hundreds of millions of liters (gallons) of water and mud trapped inside.


Updated : 2021-03-09 03:58 GMT+08:00