Whakaari/White Island eruption: Update #15

Published: Thu Dec 19 2019 12:55 PM

Volcanic Alert BulletinWI – 2019/27
Thu Dec 19 2019 1:00 PM; Whakaari/White Island Volcano
Volcanic Alert Level remains at 2
Aviation Colour Code remains at Orange

Volcanic tremor continues at a low level; gas and steam discharges continue. Further eruptions are unlikely in the next 24 hours. The Volcanic Alert Level remains at Level 2.

Since the eruption on Monday, December 9th, no further eruptive activity has occurred. The level of volcanic tremor remains low and the strong flows of steam and gases continue from the new vent area.

During the past 24 hours, camera images from the island have been clearer than earlier this week. Solar power charging of all monitoring equipment continues and both seismic stations on the island are fully operational.

Newly processed satellite radar images show that an area of the inner crater wall collapsed in a landslide during the eruption. This area had been unstable for the past year or more.

This afternoon we will be conducting an observation flight to view the vent area, eruption deposits, and the landslide scarp. This will be done by helicopter within GNS access zones; we will not be landing on the ground.

This morning a high elevation flight to monitor gas was completed, which will help us understand the magma system. We will report on results when they are available.

The expert judgement made this morning calculated the likelihood of another eruption occurring within the next 24 hours at 15 – 30 % which means another eruption is unlikely over the next 24 hours. Consequently, the distances for GNS Science staff-access zones have been reduced. This will be reviewed again tomorrow.

An explosive eruption from the main vent area remains possible and could still occur with no precursory activity, especially if there is a collapse of unstable material around one of the vents, or if the gas emission decreases allowing water to enter the vent. Sudden steam/gas eruptions from other active vents are also possible.

Should any explosive activity produce an ash cloud there remains an extremely low likelihood of ash affecting the mainland in the next 24 hours. This ash would be a nuisance only, unless someone has a respiratory disorder. Check with your GP if you are concerned.

We are providing 24-hour updates on the volcanic activity and estimates of eruption likelihood as required to support operations.

The Volcanic Alert Level remains at Level 2.

The Aviation Colour Code remains at Orange.

Volcanic Alert Level 2 indicates moderate to heightened unrest with potential for eruption hazards.

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.

Enquiries related to the emergency response should be directed to National Emergency Management Agency (NEMA).

More information will be made available within the next 24 hours, or sooner if required.

Michael Rosenberg

Duty Volcanologist

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