Mt Ruapehu's crater lake is heating up, but its 'business as usual'

Monday, 2 March 2020

Rising water temperature inside crater lake Te Wai ā-moe is a sign everything beneath Mount Ruapehu is working well, say experts.

The volcanic alert level for Mt Ruapehu remains at Level 1 following a series of 'tiny earthquakes' underneath the mountain.

Water inside crater lake Te Wai ā-moe has increased from 24 degrees Celsius to 30 degrees Celsius.

GNS Science volcanologist Michael Rosenberg said it isn't unusual to have volcanic earthquakes at Mt Ruapehu, and the rising lake temperature is a positive sign.

* Safety of Mt Ruapehu buildings reviewed after five skiers injured by falling ice

The water in the crater lake Te Wai ā-moe has increased following earthquakes beneath Mount Ruapehu (file photo).

* Climber escapes serious injury on Mt Ruapehu after 15-metre drop into crevasse**

'It's actually reassuring that something has happened because for at least nine months the crater lake temperature has sort of fluctuated in the early 20s and not much is happening,' Rosenberg said.

'To see a response like this to those earthquakes last week means the system is open, it's connected and responding. It's kind of like business as usual.'

Increased seismic activity at Ruapehu was observed during March, 2018 and 2019, September 2017, and April 2016.

Rosenberg said last week's earthquakes were located 3 kilometres beneath the volcano.

'It's just giving things a little bit of a shake up, just enough to let the gas through. These are tiny earthquakes, they're not even magnitude two, but they're enough to disturb the system and open it up a little.

'The changes are not large enough to put us into level two category where you start seeing big changes or quick changes.'

Mt Ruapehu will continue to be monitored 'minute by minute'.