Whakaari/White Island: Recent observations confirm continued elevated volcanic unrest

Published: Tue Mar 10 2020 9:30 AM

• Whakaari/White Island remains in an elevated state of unrest • Amount of volcanic gas has increased slightly compared to recent measurements but remains overall on the decline • Aerial observations confirm presence of high temperature fumaroles • The Volcanic Alert Level remains at Level 2; Aviation Colour Code remains at Yellow

As a continuation of our monitoring of Whakaari/White Island, we have conducted further aerial-based measurements and observations of the volcano in the past two weeks.

The most recent gas flight confirms the overall decline in both CO2 and SO2 output since the 9 December 2019 eruption, although latest data shows slightly elevated amounts of gas compared to recent measurements.

A helicopter-based thermal infrared survey recorded a temperature of 746 °C. This was measured on one of the lava lobes and is the hottest temperature measured to date. Despite these high fumarole temperatures, a small pond of water is present in the Primary Crater formed on 9 December 2019. Small-scale jetting of this pond water is continuing to occur, like the activity seen in September-December 2019.

High temperatures and large amounts of gas are consistent with the continued presence of shallow magma beneath the primary vent area and are within the expected range of fluctuations for post-eruptive processes. There are currently no indications for fresh magma arriving from greater depths.

The active vent area remains a rapidly changing environment and an eruption could occur with limited precursory activity. Plausible triggers for an eruption include 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.

Should any explosive activity produce an ash cloud, the likelihood of ash affecting the mainland remains very low. Under suitable weather conditions, the gas and steam plume may be noticed on the mainland as weak acid rain.

The Volcanic Alert Level remains at Level 2.

The Aviation Colour Code remains at Yellow.

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.

GNS Science and our National Geohazards Monitoring Centre continue to closely monitor Whakaari/White Island for further signs of activity. Further updates will be provided as the situation evolves.

Yannik Behr

Duty Volcanologist

Media Contact: 021 574 541 or media@gns.cri.nz