Year-long monitoring reveals declining vent temperatures at Whakaari/White Island

Published: Wed Feb 3 2021 1:15 PM

Volcanic Alert BulletinWI – 2021/01
Wed Feb 3 2021 1:15 PM; Whakaari/White Island Volcano
Volcanic Alert Level remains at 1
Aviation Colour Code remains at Green

Remote monitoring of the vent area at Whakaari / White Island that erupted in December 2019 has revealed that the temperatures of gas emissions has declined from over 700 oC to 300 oC in the last year. Recent observations suggest no eruptive activity since a series of minor steam explosions on 29 December 2020. Current activity is still characterised by steam and gas emissions at moderate-low levels. The Volcanic Alert Level remains at 1.

Over the last year, a series of thermal infrared images have been regularly collected by helicopter to observe the temperature of steam and gas vents. These temperatures have shown a gradual decline since the December 2019 eruption, from over 700 °C in February 2020 to 300 °C on 21 January 2021. The gas emission temperatures are now similar to temperatures measured in July 2018.

During January 2021, GNS Science continued monitoring of Whakaari/White Island by observation flights and measurement of gas emission rates, and with automatic earthquake, camera, and ground deformation observations. These recent observations confirmed there is no evidence of recent eruptive activity, or signs of collapse in or near the active vents. There is little water ponded on the floor of the 1978/90 Crater.

Volcanic steam and gas continue to be emitted from active vents and lava extrusions in the area that erupted in December 2019. The most recent observations are some of the lowest gas emissions measured since the 2019 eruption and are now close to those observed in early-2019.

The Volcanic Alert Level remains at 1 and the Aviation Colour Code remains at Green.

The Volcanic Alert Level reflects the current level of volcanic unrest or activity and is not a forecast of future activity. Volcanic Alert Level 1 indicates the primary hazards are those expected during volcanic unrest; including discharge of steam and hot volcanic gases, earthquakes, landslides and hydrothermal activity. While Volcanic Alert Level 1 is mostly associated with environmental hazards, eruptions can still occur with little or no warning. The main plausible triggers for a sudden eruption remain the collapse of unstable material in an active vent and the possible ingress of water underground onto the shallow magma body.

Further information about the volcanic alert levels and what they mean can be found here.

GNS Science and the National Geohazards Monitoring Centre continue to closely monitor Whakaari for further changes in unrest. GeoNet monitors Whakaari via a network of seismic and acoustic sensors, GNSS (GPS) receivers, cameras, and gas and visual observations.

Steven Sherburn Duty Volcanologist Media Contact: 021 574 541 or media@gns.cri.nz