Observation flights and satellite data have confirmed “near continuous” emissions of small amounts of volcanic ash from an active vent at Whakaari/White Island, volcanologists say.
GNS Science duty volcanologist Oliver Lamb said recent observations were consistent with minor eruptive activity.
“Therefore, the volcanic alert level remains at Level 3. The continued presence of volcanic ash emissions mean that the aviation colour code remains Orange.”
The volcanic island, 48km offshore of Whakatāne, had its alert raised in April.
The ash could be seen from the Bay of Plenty coast either as a hazy plume trailing downwind from the volcano or as a vertical plume above the volcano, depending on the wind strength and direction.
Several advisories had been issued for the airborne volcanic plume when it encroached into active airspace, resulting in some flight cancellations.
Four Air New Zealand flights were cancelled at Tauranga Airport due to ash in the air on Sunday.
Lamb said the plume had at times travelled above the Bay of Plenty coast but the amount of ash it carried was small and not expected to fall back on the mainland.
Vent temperatures had increased to around 460C, still well below the temperatures of up to 650C measured in 2020 and 2021.
Lamb said some “minor night glow” had been captured by the camera at Te Kaha which was consistent with these higher vent temperatures.
“This ‘glow’ is only visible in the near infra-red with our camera and unlikely to be visible with the naked eye.”
He added that there had been a decrease in new impact craters near the vent during recent observation flights which indicated less explosive activity.
“Due to our lack of on-island monitoring, it is possible that short-duration eruptions are occurring without being directly recorded.”
Emergency Management Minister Mark Mitchell said he was “cautiously optimistic” that scientists would be able to get back on the island soon to fix broken technology.
“It’s something that is complicated, unfortunately, and I didn’t anticipate that it would be,” he told 1News earlier this month.