An expedition to Mt. Ruapehu’s crater lake today has confirmed that a small eruption occurred at the volcano on Wednesday night.
Earthquake activity was recorded at the volcano between 10:24 p.m. on Wednesday 4th and 5:19 a.m. on Thursday 5th of October, and a volcanic earthquake registered on monitoring equipment at about 10:30 p.m. on Wednesday night.
However, cold southerly weather which brought snow to the central plateau prevented scientists visiting or flying over the volcano’s crater lake to survey possible eruption damage until today.
This morning’s expedition has determined that a small eruption has taken place within Ruapehu’s crater, causing waves up to 5 metres in height to wash the lake’s rim. As a result, the crater lake’s level has risen by a metre and its temperature has risen 7.5 °C to 22.5 °C.
In a media release late this afternoon, Brad Scott, Duty Volcanologist for GNS Science, described the effects of the eruption as minimal and confined to the lake basin, with wave action insufficiently high to flow over the tephra dam and form a lahar.
He said that the temperature and water level change were to be expected after such an eruption, and noted that no further volcanic earthquakes or tremor had been recorded over the last 24 hours in his release at 4:30 this afternoon.