Volcanic Ash From Whakaari Halts Flights – Expert Reaction

Thursday, 22 August 2024, 3:32 pm
Press Release: Science Media Centre

Volcanic ash from an eruption on Whakaari/White Island caused flight delays and cancellations for airports in the Bay of Plenty this morning.

The Volcanic Alert Level for Whakaari was raised to Level 3 on 9 August 2024, and since then the volcano has experienced ongoing minor eruptive activity including ash emissions. Last week, GNS Science said a new vent had been detected on Whakaari/White Island.

The SMC asked experts to comment.

Dr Simon Barker, Rutherford Discovery Fellow, Senior Researcher, Victoria University of Wellington, comments:

“Whakaari has produced a series of small ash-producing eruptions that have resulted in a visible grey plume from the mainland. Most of the ash within this plume has been distributed by the dominant westerly winds over the sea. Volcanic ash can be damaging to aircraft engines and flights have been cancelled as a standard precaution with changing wind directions and ash particles in the atmosphere around this region.

“The biggest issue with Whakaari at the moment is the number of unknowns with the lack of monitoring on the island due to the 2019 eruption and restricted access preventing the repair of seismic and geodetic networks. This makes it difficult to place the ongoing activity within the context of past eruptive episodes and to assess how the system is changing. Gas flights, drone footage and ash emissions all suggest that magma is very close to the surface and therefore this activity could continue for some time.

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“Whakaari is known for producing small eruptions and it is unlikely that a significant eruption will occur. However, recent marine sediment cores collected in this region show that larger eruptions have happened in the geological past. This highlights the importance of re-establishing monitoring and ongoing research on Whakaari.”

No conflicts of interest

Dr Adrian Pittari, Senior Lecturer – Earth Sciences, University of Waikato, comments:

“Volcanic ash is the fine ‘dusty’ volcanic glass and rock particles carried within eruption plumes, that rise into the atmosphere and then downwind by air currents.

“Ash in volcanic plumes is considered a hazard to aeroplanes flying in affected airspace because it is sucked into their engines potentially clogging fuel lines, sticking onto engine surfaces and eroding parts. It can also interfere with electrical and computer systems, infiltrate cabin space and reduce visibility. The level of ash concentration in the atmosphere and the flight time in affected airspace are important considerations.

“There were two well-known extreme cases in the 1980s of Boeing 747 jet planes that flew through concentrated ash plumes in Alaska and Indonesia and temporarily lost power to all engines, and there have been many other minor ash encounters with aircraft. There is a global network of Volcanic Ash Advisory Centres (VAAC) which monitor ash plumes and weather patterns, and inform the aviation industry on where to expect airborne ash hazard. This helps airlines to plan flight paths and cancellations in areas of volcanic eruptions.

“Whakaari has been undergoing a period of minor eruptive activity since May and increased ash has been detected in the plume since August 9. This morning the wind has been northerly, hence blowing towards the mainland Bay of Plenty. Ash is only falling to the ground/sea surface close to Whakaari and has not fallen on the ground near the Bay of Plenty coast. However it is the high airborne ash in the vicinity of flight paths that is the main concern to airlines.”

No conflicts of interest declared

Professor Ben Kennedy, School of Earth and Environment, University of Canterbury, comments:

“The ongoing small ash eruptions and gas plume from Whakaari are expected for this volcano and has been ongoing over the past weeks.

“The current wind direction means that the gas plume containing suspended ash is drifting across mainland NZ, and so disrupting airspace more than normal. Over previous weeks, the prevailing winds have carried this gas plume out to sea, where it can be more easily avoided.

“Satellite images and meteorological forecasts allow GNS to monitor the situation closely and maintain clear communications with air and marine traffic that pass close to or downwind of the island. There is no current data that indicates that eruption will grow significantly in size, however, more data is needed to fully assess this possibility.

“Ash and volcanic gas can be damaging to engines and human health and so should be avoided.”

No conflicts of interest declared

Dr Shane Cronin, Professor of Volcanology, The University of Auckland, comments:

“The current situation at Whakaari is characterised by an open-vent. The level of this activity is likely to remain “annoying” for a while if this magnitude of eruption continues. By annoying, I mean that the semi-regular puffs of steam and gas cause unease as well as justified precautionary reactions by the aviation community. The ash content of the plume is generally low and this is of low hazard to people – the threat to aircraft is well known and precautions are well advised. Variations in wind will mean that sometimes the plume may reach the mainland. This will bring with it small amounts of gas and possibly some fine dusting of ash. The open vent situation is in many ways comforting, because this allows a relatively free and steady release of gas and magma pressure. This means that sudden large explosions are less likely – these are caused by trapped gas and a blocked-vent situation such as was the case in 2019.

“The key question for us all in the NZ volcano science community is what will happen next. The problem in answering that is that there is currently no working seismic station on the island. Without on-ground measurements we can only guess at how much magma is rising to the surface and driving this current phase of eruption. We can have some degree of educated estimation using gas measurements (from aircraft) and satellite topographic change information (using Synthetic Aperture Radar SAR), but neither of these techniques is of high-enough resolution or sampling frequency to give real-time results. Gas flights depend on the weather and are relatively expensive and infrequent, SAR passes to compare between images are also irregular and require so much processing that small-area changes on the scale of the vent area are not well resolved.

“We are in this crazy situation with a community of scientists that have built up world-class volcanic science knowledge and an array of skills including machine-learning techniques for automated forecasting but no way of using them at present for this volcano, because a mess of convoluted legal red tape is stopping GNS Science from being able to re-install the seismic stations.”

No conflicts of interest declared

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