Whakaari/White Island unrest: Alert level rises

The Volcanic Alert Level for Whakaari/White Island has been raised to Level 3, while the Aviation Colour Code remains at Orange.

GNS Scientists monitoring the gradual increase in volcanic activity at Whakaari/White Island have raised the Volcanic Alert Level to Level 3 while the Aviation Colour Code remains at Orange.

In the past few months, volcanic ash has been identified more frequently in the Whakaari/White Island steam and gas plume.

Evidence of intermittent explosive activity has also been observed during recent observation and gas flights.

Duty volcanologist Geoff Kilgour said despite limited direct observations of activity in the last few weeks, images from the webcams at Whakatāne and Te Kaha continued to record an increase in volcanic ash in the steam and gas plume at Whakaari/White Island.

“Over the same period, our colleagues at MetService have been able to detect minor amounts of volcanic ash in the plume using satellite imagery,” Kilgour said.

“From the coast, this can be seen as a hazy plume trailing downwind from the volcano.”

Kilgour said these observations indicated there had been a gradual increase in eruptive activity, and in response, the Volcanic Alert Level is now raised to Level 3.

Kilgour said volcanic ash emissions remained minor, and during periods of northerly winds, residents on the coast may notice the plume of gas and ash as sulphur odours.

“We do not expect ash fall to affect the Bay of Plenty coastline at this time.

“During recent observation flights, we have observed impact craters on the main crater floor, indicating that on occasions, more explosive activity has occurred, ejecting rocks several hundreds of metres away from the vent.”

The volcanologist said explosive events like these are common at Whakaari as active vents grow, periodically become clogged, or gas flux increases.

“Monitoring data from our gas flights, thermal InfraRed temperature measurements and the sulphur dioxide (SO₂) emissions detected by satellite, all show slight increases, which is consistent with an overall increase in volcanic activity, and more frequent ash emissions.”

Kilgour said steam, gas, and volcanic ash emissions remained variable as they had been for the past few months.

“And due to our lack of on-island monitoring, it is possible that short-duration eruptions are occurring without being directly recorded.”

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He said recent activity was consistent with a low level of eruptive activity.

“The continued presence of volcanic ash emissions mean that the Aviation Colour Code remains Orange. These levels acknowledge the gradually increased volcanic activity but also reflect the increased level of uncertainty.”

GNS Science’s Volcano Monitoring Group and National Geohazards Monitoring Centre will continue to closely monitor Whakaari/White Island for any changes in activity.

“Without sensors on the island, our monitoring continues to rely on remote cameras, satellite imagery, and periodic observation and gas flights to monitor Whakaari.

“We will provide further updates when information becomes available.”