Mount Ruapehu - What’s happening under the hood
There’s currently an increase in volcanic unrest occurring at Mt Ruapehu, so this is a good time to check out some background information on this magnificent volcano. It is now almost 15 years since the last eruption in September 2007.
The history of eruptions at Ruapehu
Mt Ruapehu remains one of our most active cone volcanoes. From our catalogue of observed volcanic activity since the 1830s, there are over 600 days of activity at Mt Ruapehu. From the catalogue we have also learnt that small eruptions only affect the summit plateau around the Crater Lake (Te Wai ā-moe), with larger, lahar generating eruptions occurring on average about once every 7 years. Noting averages are not always a great measure as volcanic activity is often clustered into episodes.
The most recent significant eruption was 25 September 2007, this was an explosive eruption, lasting about 7 minutes. During the eruption, explosions spread ash, rocks and water across the summit plateau, and produced lahars in two valleys including one in the Whakapapa ski field.