Volcano Alert Bulletins (VABs) are New Zealand's official source of volcano status information including the current Volcanic Alert Level (VAL).
They are issued on an as needed basis summarising the volcano status and recent events.
They can indicate if activity is increasing, decreasing, or in a steady state. They may contain forecasts, highlight developing, or expected problems.
If you’d like to be notified as soon as we issue a new bulletin, our social media channels and the GeoNet app will keep you up-to-date.
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. The Volcanic Alert Level remains at 1.
Measured changes in Crater Lake water and gas composition confirm the slightly elevated level of activity at Mt Ruapehu. The lake temperature (37ºC) and the level of seismic tremor remain unchanged. The Volcanic Alert Level remains at 1.
An increase in volcanic gas emissions and sustained high lake temperature suggest a slightly higher level of activity at Mt Ruapehu. The Volcanic Alert Level remains at 1.
Observations during visits to White Island over the last 3-4 months confirm that activity remains at low levels. Activity is confined to the gas rich vents on the western side of the active crater. Hot, clear gas continues to be emitted. Some water has ponded on the floor of the active crater but no permanent lake has reformed. The seismic and acoustic activity generally remain low, and the SO2 gas flux is slowly declining.
Since early September, Mt Ruapehu’s Crater Lake had been heating at a rate of around 1°C per day, reaching a maximum of 40ºC on October 4. The lake temperature has cooled slightly since then and is now hovering around 37°C. After October 18, the level of volcanic tremor under Mt Ruapehu increased in strength. Volcanic tremor is always present at Mt Ruapehu, however the level can vary.
Observations during a visit to White Island on Friday have confirmed that a large part of the gas is now being emitted from one ‘joint’ vent on the lava outcrop at the back of the crater. The joining of the vents has resulted in a stronger and noisier gas flow from this vent. The temperature has declined slightly, it is now only 250 °C, down from 300 °C.
This morning, steam plumes have been visible above Mt Ruapehu’s Crater Lake. The lake temperature is now 37 ºC as part of a heating episode that began around 2-3 September 2016. No seismic or acoustic activity has been recorded this morning, indicating the steam plume was not generated by activity in the lake. The Volcanic Alert Level for Mt Ruapehu remains at Level 1 (minor volcanic unrest) and the Aviation Colour Code also remains unchanged at Green.
No further sustained eruptive activity has been observed at White Island. As a consequence the Volcanic Alert Level has been lowered to Level 1. The Aviation Colour code remains Yellow.
Observations from a visit to White Island on Wednesday suggest that the minor ash emission that occurred on Tuesday 13 September 2016 has ceased. The Volcanic Alert Level is lowered to 2, and the Aviation Colour code is lowered to Yellow.
Monitoring data available from the island confirms there has been no escalation in the level of activity and the emission of ash is currently very minor.