Volcanic Alert Level remains at 1 Aviation Colour Code remains at Green
Carbon Dioxide (CO2) gas emission rates at Mt Ruapehu have returned to a more normal level. The period of slightly higher volcanic unrest appears to have ended. On December 5 the Carbon Dioxide (CO2) gas emission rate at Mt Ruapehu was measured as 440 tonnes/day, a substantial reduction from the rate of 2290 tonnes/day measured on November 23.
An emission rate of 440 tonnes/day is less than the average emission rate over the last 10 years.
Emission rates of Sulphur Dioxide (SO2) and Hydrogen Sulphide (H2S), were also measured on December 5, both well below measurements from November 23. No additional water or gas composition data have been collected from the Crater Lake (Te Wai ā-Moe) since mid-November. Over the last two weeks the volcanic tremor at Mt Ruapehu has been at low or moderate levels, but the strongest since late 2016.
The lake temperature has risen from 36 oC to 38 oC in the last week, evidence of continued heat entering the lake.
The period of slightly higher volcanic unrest, which was inferred largely from the high CO2 gas emission rate measured on November 23, now appears to have ended.