Volcanic unrest continues on Whakaari White Island

An aerial view of Whakaari White Island after the volcanic eruption in December 2019. Photo / NZME

Geonet says volcanic unrest is continuing at Whakaari White Island.

Recent gas and observation flights at the marine volcano show increases in gas emissions and lake level, as the anniversary of the island's fatal December 2019 eruption approaches.

In a statement, Geonet said the vent temperatures remain steady around 200-220 degrees and "spectacular steam and gas plumes" have been sighted recently.

"The volcano occasionally emits traces of volcanic ash and remains in a state of moderate to heightened unrest."

GNS scientists undertook a visual observation flight and a gas emission measurement flight last week where temperature measurements of the active vent area were also completed.

The results showed emissions of volcanic gases had increased since the last measurements on October 14.

Whakaari/White Island Update: Volcanic unrest continues, increased gas emission, steady active vent temperatures and lake level rise. Read the full bulletin here: https://t.co/Y0ZYlfP14A pic.twitter.com/mMNIHxGwNb

— GeoNet (@geonet) November 9, 2021

Sulphur dioxide was up to 681 tonnes per day from 267 tonnes per day in mid-October.

The emissions of carbon dioxide increased from 757 to 2712 tonnes per day, while the hydrogen sulphide also showed an increase, from 10 to 38 tonnes per day.

"These data show another pulse of gas escaping from the molten material at depth in the volcano," said Geonet.

Temperatures measured in the active vent area ranged from 202 to 252 degrees during September-October. In July and August, the temperatures were more than 500-600 degrees.

Geonet said the level of water in the crater lake was slightly higher than observed in late October - nearly all of it due to heavy rainfall.

"Very weak ash emission was occurring during the observations last week, but the recent deposits are minor and only visible close to the active vents. Intermittent ash emission is still possible."

And weather conditions were allowing for "spectacular steam and gas plumes" sightings above the island.

Seismic activity from the degraded site remained similar, with low levels of volcanic tremor and occasional low-frequency volcanic earthquakes.

It said the current level of activity was consistent with moderate to heightened levels of unrest.

"The volcanic alert level reflects the current level of volcanic unrest or activity and is not a forecast of future activity."

December will mark two years since the White Island eruption that killed 22 of the 47 people on the island, most of them international tourists. Many more were injured.