Published: Tue Aug 24 2021 2:00 PM
A short-lived period of minor ash emission occurred at Whakaari/White Island on Sunday 22 August 2021. The Volcanic Alert Level remains at 2
At about 7:40 AM on Sunday 22 August 2021, a period of minor ash emission was observed from the active vent area at Whakaari/White Island. Based on webcam observations, the ash emission persisted for about two minutes. It was not visible in camera images from Whakatane. Based on the short duration of the activity, it is unlikely to have produced a plume large enough to create any ashfall, even on the island.
At 7:00 PM on Thursday 19 August 2021, a notable volcanic earthquake was recorded at Whakaari/White Island. The earthquake continued for about 10 minutes, but it was not accompanied by any eruptive activity that could be observed, either by webcam images, or by air pressure sensors. No relationship has been established between the volcanic earthquake and the minor ash emission three days later. Other seismic activity at the volcano has been minor.
Webcam images continue to show night glow, suggesting that temperatures in the active vent area probably remain around 500-600°C, like recent observations.
Satellite radar data continue to show small amounts of ground deformation around the active vent and lake area.
These observations do not change recent interpretations that a fresh magma intrusion to shallow levels has occurred since June 2021. The ash emission observed on Sunday may be related to shallow magma beneath the active vents, but its short duration suggests that unstable material falling into the active vent, subsequently to be fragmented and then ejected by gas pressure, may be a more likely explanation. This type of activity has occurred many times in the past, including since the December 2019 eruption (an example here).
Equipment that provides real-time monitoring on the island is currently degraded and we are continuing to work on restoration options.
The current level of activity is consistent with moderate levels of unrest. As such the Volcanic Alert Level remains at 2 and the Aviation Colour Code remains at Yellow.
The Volcanic Alert Level reflects the current level of volcanic unrest or activity and is not a forecast of future activity. While Volcanic Alert Level 2 is mostly associated with volcanic unrest hazards (including discharge of steam and hot volcanic gases, earthquakes, landslides and hydrothermal activity), potential for eruption hazards also exists and eruptions can still occur with little or no warning.
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 monitor Whakaari/White Island for further changes in unrest.
Steven Sherburn Duty Volcanologist
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