Time lapse of the White Island crater floor January 15th - 16th, 2020.
Images / Institute of Geological and Nuclear Sciences
While minor volcanic unrest continues, Whakaari White Island's alert level has been lowered from 2 to 1.
The submarine volcano has not been at Level 1 since November last year.
It was raised to Level 2 on November 18, three weeks before the island erupted, fatally injuring 21 people visitingat the time and leaving more than a dozen others critically injured.
The move to Volcano Alert Level 1 does not completely rule out the possibility of eruptions occurring with little or no warning, a volcanic alert bulletin from GNS Science said today.
Whakaari White Island crater floor webcam image at 11.00am June 9 2020. Photo / GeoNet
The bulletin read: "Based on the slowly decreasing level of volcanic activity and confirmation that the recently observed gas pulse was short-lived, the Volcanic Alert Level for Whakaari/White Island is now lowered to Level 1.
"The Aviation Colour Code remains at Yellow."
The bulletin said observations and monitoring data over the last few months indicated that Whakaari/White Island has been progressing on a gradual trend back to lower levels of unrest that are typical of the long-term behaviour of this volcano.
Aerial view of Whakaari/White Island after the volcanic eruption on December 9. Photo / File
The decision to lower the Volcanic Alert Level to Level 1 is not as a result of recent changes in a single data set, instead, it is based on the GNS Science volcano monitoring team's collective interpretation of all the monitoring data and of their trend over the past few months.
"The data sets considered in our interpretation include discharge rate of sulphur dioxide (SO2) and carbon dioxide (CO2) gases, seismic activity, and the temperature of the discharging gases around the December 2019 eruption vents," the bulletin said.
"While the temperature of the gas vents remains high, over 450C, some cooling has been observed over the last few months, indicating a slow decline in heat input from depth.
"The hot gases that are being emitted from gas vents around the December 2019 eruption vents are still sufficiently hot and are generating a 'night glow' that continues to be seen on GeoNet's night-vision webcams."
White Island's Volcanic Alert Level has been lowered to Level 1. Photo / File
NZ volcano alerts
Meanwhile, lead agencies involved in the Whakaari/White Island Recovery Project are reminding the public that a drop in Volcanic Alert Level is not a sign that it's safe, or permitted, for anyone to return to the island.
Bay of Plenty Regional Council Volcanology Team Leader Nico Fournier says the Volcanic Alert Level is not a forecast of future activity.
"A volcano's Alert Level communicates the status of the volcano – its current activity, state of unrest and expected hazards. Volcanic Alert Bulletins are issued to communicate the status of the volcano and any risk and hazards that our monitoring team are seeing.
"Recent monitoring of Whakaari/White Island by our scientists has shown that activity has decreased to where it is currently considered 'minor volcanic unrest'. This has prompted us to lower the Alert Level."
Whakaari/White Island recovery project manager Craig Morris says representatives of recovery partner agencies and groups including GNS Science, NZ Police, Department of Internal Affairs and WorksafeNZ have always been mindful of the consequences of a change in Volcanic Alert Level.
"Even with the recommencement of marine activity post Covid-19 restrictions, Whakaari remains off limits.
"Whakaari is a privately owned Island. Its owners only allow access to individual persons or organisations specifically authorised by them. Any landing by unauthorised persons will be unlawful and will be subject to police intervention," Morris said.
This move indicates the most likely hazards are those expected during lower levels of volcanic unrest; steam discharge, volcanic gases, earthquakes, landslides and hydrothermal activity.
