News and activity reports about Ruapehu volcano:
Ruapehu volcano (New Zealand): signs of unrest, alert level raised
New Zealand scientists monitoring Ruapehu volcano detected signs of increased volcanic unrest and raised the alert level of the volcano. The likelihood of new eruptions over the next weeks to months has increased, GNS Science said in their latest press release.
GNS scientists recorded increasing numbers of small earthquakes about 5 km beneath the summit area of Ruapehu, and think that the temperature at vents at the bottom of the lake is around 800 deg C, although the lake itself is only 20 deg C and has decreased its temperature since January this year.
"This suggests the vent is partly blocked which may be leading to a pressure build-up beneath Crater Lake. A sudden release of the pressure may lead to an eruption", GeoNet writes.
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Sunday morning at 10:47 am local time, a section of Ruapehu volcano's crater walls collapsed under the pressure of the crater lake. The sudden draining of the lake caused a devastating lahar that travelled down from its altitude at 2500 m to sea level. Fortunately, the flash flood of mud drained through a river channel and no people were injured or killed. Authorities closed roads and the nation's main trunk rail track near the southern base of the mountain on New Zealand's North Island.
A similar event happened in 1953 killed when a lahar killed 151 people when it washed away a rail bridge, plunging a passenger train into the raging torrent of mud.