Whakaari/White Island remains in an elevated state of volcanic unrest, Geonet has announced today.
Gas flux has varied above background levels and was elevated in the latest observation flight, Duty Volcanologist Yannik Behr said.
Other monitoring parameters mostly remain within the range observed over the past two months, he said.
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The volcanic alert level remains at level 2 and the aviation colour code remains
"GNS Science volcanologists have recently reinstated gas and observation flights over
Whakaari/White Island for the first time since Covid-19 restrictions were put into place," Behr said.
"Results from the most recent gas flight on May 27 indicate an increased gas
flux since the previous flight on May 20."
While previous observations indicated a trend back to levels that are typical for this volcano, Behr said the recent increase in SO2 and CO2 gas flux, one of our main indicators of volcanic unrest, could be attributed to a new batch of the magma beneath the volcano at shallow depth, the volcanologist believed.
"Thermal infrared images, taken during the observation flight on May 20, show the lava extrusions, first detected in early January, are still very hot, at around 500 degrees Celsius.
"Hot gases that are being emitted around these lava lobes generate a 'night glow' that can be seen on GeoNet's night vision webcams."
Behr said the team were still observing occasional episodes of slightly elevated tremor, albeit overall tremor levels remain low and within background levels for the volcano.
This week Behr recorded some shallow source volcanic earthquakes.
Satellite-based measurements of ground deformation showed the ground about the active vent area had subsided by several centimetres since the December 2019 eruption, he said.
"Our recent observations are consistent with a volcanic system that is still very dynamic,
despite several monitoring parameters trending back towards pre-eruption levels.
"An eruption could occur with little precursory activity. Plausible triggers for an eruption
remain the collapse of unstable material around the vents, sudden release of gas from
the magma, and the rapid ingress of water onto the shallow magma body."
The likelihood of ash affecting the mainland remained very low, Behr said, should any explosive activity produce an ash cloud.
"Under suitable weather conditions, the gas and steam plume may be noticed on the mainland as weak acid rain.
What does the alert level mean?
• Volcanic alert level 2 indicates moderate-to-heightened unrest with potential for eruption hazards, including unpredictable and life-threatening steam-driven eruptions.
• The volcanic alert level reflects the current level of volcanic activity and is not a forecast of future activity.