Whakaari/White Island likelihood of future eruption: Update #6
Expert judgement this morning is that there is a 30-40% chance (unlikely) of an eruption occurring that could impact outside of the vent area within the next 24 hours. This has decreased slightly compared to yesterday.
What happened?
On Monday 9 December at 2:11pm an eruption occurred at Whakaari/White Island, with devastating impacts for people on the island at the time, their families, and wider New Zealand.
Future scenario
At 11:50 am 16 December, GNS Science volcanologists reviewed all available data and updated the likelihood of an eruption that would impact beyond the vent area (marked in the image below) occurring within the next 24 hours.
Their new calculation was that there is a 30-40% chance (unlikely) of an eruption occurring that could impact outside of the marked vent area within the next 24 hours.
Photo of Whakaari/White Island from 2004, showing the marked vent area.
Click image to make it larger. The distance between the edge of the crater lake and the ocean at the bottom of the image is about 700m.
How does this compare to previous estimates?
The expert judgement of the likelihood of an eruption has decreased slightly since yesterday (Sunday 15 December 2019).
Likelihood of eruption over time at Whakaari/White Island by expert judgement - 16 December 2019
The table above shows the expert judgement of eruption likelihoods for time periods before and after the eruption. The table shows that the likelihood of an eruption is now about 100 times higher than in early December.
Since 2013, eruption likelihoods for Whakaari have been calculated via expert judgement as part of internal staff health and safety procedures. Our expert scientists calculate the risk for all volcanoes at Volcanic Alert Level 1 or higher. The time periods used for the expert judgements vary depending on the level of activity at the volcano – when activity increases, we do expert judgements more often and for a shorter time window to reflect the changing situation.
Since the eruption on 9 December, eruption likelihoods have been calculated for a 24-hour time period. For 29 October and 2 December (before the eruption), eruption likelihoods were calculated for 4-week and 13-week time windows respectively and have been converted in this table to reflect relevant 24-hour time windows for comparison.
The Volcanic Alert Level is not linked directly to risk and likelihoods but describes the level of current volcanic activity.
Attributable to: Natalia Deligne, GNS Science Volcanic Hazard and Risk Modeller
Media contact: 021 574 541 or media@gns.cri.nz