Ruapehu Development

 

The Crater Lake (Te Wai ā-moe) temperature started to rise since mid-July.

A heating phase has revealed the temperature rising from 11 °C to 26 °C today. With the lake heating nowadays, the flow into the lake initially increased to about 300 MW, currently at 200 MW values.
However, the Crater Lake may experience a drop in temperature due to occasional snow melting and/or heavy rainfall feeding the lake as happened on 28 August (see a sharp drop in the attached image).

However, these short-term variations do not affect the long-term heating or cooling trends.
On 23 August, water samples were taken to analyze the lake's geochemistry values. Investigations indicate that samples are within range levels. Moreover, gas isotope data suggests that the lake is being driven by a new magma batch in the system, which explains its heating episode.
The volcanic tremor continues at low levels, although several earthquakes have been registered beneath the edifice.
Ground-based measurements of sulfur dioxide (SO2) concentrations show low-to-moderate levels over the past month.
The heating period is associated with the ongoing tremor, SO2 emissions and minor changes in the lake chemistry.
Thus, The Volcanic Alert Level remains at 1 and the Aviation Colour Code at Green.
Source: GNS Science volcano activity update 5 September 2023