Week in Review

A level two sense of security

Whakaari-White Island has been at a level two alert level 10 times since 2012, but Monday was the first time it went from level two to an eruption.

While tour operators felt this level was within operating guidelines, some experts say the eruption wasn't wholly unexpected and even a "disaster waiting to happen". 

Data gained from GeoNet website bulletins shows the alert level has reached two twice this year. It also reached the level in 2016, 2013 and 2012.

The bulletins show that yesterday’s eruption was the first time an alert level of two led to an eruption. Eruptions in 2016 occurred when the alert level was at one.

Monitoring at Whakaari-White Island includes earthquake activity, volcanic tremor, gas flux, acoustic signals and visual images from the web cameras. There are also regular soil gas surveys, sampling of springs and gas vents, ground deformation and magnetic surveys.

Whakaari-White Island's alert levels. Data source: GeoNet Volcanic Alert Bulletins

University of Canterbury associate professor Thomas Wilson described the alert system as a way for volcanologists to describe what’s going on with a volcano. 

“It’s a crude analogy to a weather forecast. They’re not trying to forecast into the future, they’re trying to explain what’s happening with the volcano.”

Level zero is the level a dormant volcano would have. Level one, means some activity is occurring.

“When you get to level two, that’s when things change a bit.”

This is when there’s heightened unrest with a heightened risk of eruption.

“Anything above two is when there’s an eruption going on.”

For Whakaari-White Island, Wilson said he knows operators do have a relationship with GNS. 

“White Island has been a disaster waiting to happen for many years. Having visited it twice, I have always felt that it was too dangerous to allow the daily tour groups that visit the uninhabited island volcano by boat and helicopter.”

“It’s a bit like anything for any touristic operator, they’re needing to assess the risk within the statutory obligations which they have.”

He didn’t want to be drawn on the current tragedy but did think a conversation should be had around how risk should be managed at New Zealand’s touristic volcanoes.

“Most of these are in the conservation estate and managed by DoC [Department of Conservation] and various iwi.”

In 2012 after Tongariro National Park's Mount Tongariro erupted, parts of the alpine crossing were closed for months. The alert level for the area was a one or two, but DoC was unwilling to send workers in to repair parts of track damaged by the eruption until the risk level was reduced.

Whakaari-White Island has been privately-owned by the Buttle family since 1936.

Around 10,000 people visit the active volcano every year. According to one tour operator, visiting during a level two alert was in its operating guidelines. A level three alert  - where small eruptions could be occurring - meant it would liaise closer with scientists monitoring the island. 

Visitors to the island can only land as part of a guided tour. Costs range from $229 an adult by boat, to $730 a passenger by air. A tour guide from one of the companies is among the deceased.

Monash University professor Ray Cas thinks Whakaari-White Island is too risky for tourists.

“White Island has been a disaster waiting to happen for many years. Having visited it twice, I have always felt that it was too dangerous to allow the daily tour groups that visit the uninhabited island volcano by boat and helicopter.”

University of East Anglia’s Dr Jessica Johnson said the eruption was “unfortunate but not completely unexpected”.

“Levels of activity at White Island/Whakaari have been relatively high since September, and even more elevated over the last couple of weeks, with increased numbers of small earthquakes and more volcanic gas detected than usual. As a consequence, the volcanic alert level was raised.”

New Zealand's volcanic alert system. Image: GeoNet CC BY 3.0 NZ

What’s happening in a Level 2 alert

Most of the time Whakaari-White Island is at level one, “brewing” and bubbling as a normal active volcano.

Ten times since 2012 it has reached level two or above.

A bulletin published by GeoNet on December 3 assessed the alert level as two. Heightened activity that had been observed mid-November was still occurring with mud and debris being thrown 20 to 30 metres in the air. This was on the far side of the crater lake, said the bulletin. “The current level of activity does not pose a direct hazard to visitors.” 

It went on to note the risk of eruption: “These eruptions can occur with little or no warning.”

In June, after swarms of earthquakes, the level was also raised to two with sulphur dioxide levels at the highest since 2013.

Level two was also assigned in 2016 after an eruption. The bulletin at that time explained "… staff will not be visiting the main crater floor until further notice due to the heightened state of volcanic unrest”. Monitoring would be done with existing instruments and from a “safe distance”.

In 2013 it was raised to level two after a short explosion.

“This eruption is larger than recent events and would have been life-threatening to people on the island.”

In 2012, a lava dome was spotted and the alert level raised from one to two. This was the first time a lava dome had been seen forming. According to the bulletin, it was tour operators who spotted it first: 

“Comments from tour operators at White Island suggest the dome may have been visible for two weeks, but not as clearly as Monday. How long the dome has been growing is unknown, but possibly since the ash eruption in early August.”

The alert level was raised with the warning:

“Our concern is that lava dome growth can be accompanied by explosive eruptions and could impact people on the island.”

A criminal investigation into the deaths and injuries will be completed by police. Worksafe will complete a work and safety investigation

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