Whakaari/White Island eruption: Update #12

Published: Mon Dec 16 2019 1:40 PM

Volcanic Alert BulletinWI – 2019/24
Mon Dec 16 2019 1:30 PM; Whakaari/White Island Volcano
Volcanic Alert Level remains at 2
Aviation Colour Code remains at Orange

The level of volcanic tremor has remained low over the weekend and this morning (16 December) at Whakaari/White Island. No eruptions have occurred since Monday 9 December and further eruptions are unlikely in the next 24 hours. The Volcanic Alert Level remains at Level 2.

An eruption occurred at Whakaari/White Island at 2:11pm on Monday 9 December, with a devastating impact for those on the island at the time, their families, and wider New Zealand. We are holding families affected in our thoughts.

Since the eruption on Monday, December 9th, there has been no further significant eruptive activity and the level of volcanic tremor remains low.

The expert judgement made this morning calculated the likelihood of another eruption within the next 24 hours at 30 – 40%. This decrease in likelihood means another eruption is unlikely over the next 24 hours. Following this likelihood reduction, the distances for GNS Science staff access zones have reduced in line with this.

Aerial observations on Saturday and Sunday (14 and 15 December) have provided additional information about the active vent area. There are three main vents within a 100-metre square area. One is producing transparent high temperature gas, indicative of a shallow magma source that is within a few tens of metres below the surface. This open hot vent is responsible for the glow seen in night time images.

An explosive eruption can still occur with no precursory activity from this vent especially if there is a collapse of unstable material around the vent, or if the gas emission decreases allowing groundwater to enter the vent.

The other vents are also producing large amounts of steam and gas and sudden steam/gas eruptions from them are still possible.

As the wind shifts to become more northerly today, gas might be noticed in the Ōpōtiki to Whakatāne area, as occurred on many occasions during the 1976 to 2000 eruptive period. People may feel this gas as a slight irritant on skin or eyes. Should any explosive activity produce an ash cloud, the anticipated impact on the mainland is very low. If ash did reach the mainland it would be more of a nuisance or disruption and not life threatening.

A 133 km deep earthquake last night in Bay of Plenty, although widely felt, did not cause any change in activity at the volcano.

Some monitoring equipment is partially buried under ash and the batteries at one site have gone flat. This has affected one of our three cameras. We still receive data from the remaining equipment, which allows us to continue monitoring the volcano. Both seismic stations on the island are fully operational and are providing us with round the clock data.

We will continue to provide daily updates on activity unless the situation changes.

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.

Craig Miller

Duty Volcanologist

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