New Zealand's New Alert System for White Island Could Save Lives

The Whakaari or White Island eruption tragedy prompted researchers to develop a new warning alert system for volcanic eruptions in New Zealand and elsewhere. The scientists' research has shown that advance warnings for eruptions are possible due to the occurrence of seismic activity patterns. Their study is published in Nature Communications.

This new system can raise an alert 16 hours before a volcanic eruption. It is automated and can provide real-time information on hazards with a higher safety level. The study made use of machine learning algorithms and the latest monitoring data continuously collected from the last ten years.

In the past ten years, five eruptions were recorded from Whakaari. Data shows that destructive eruptions can be expected every 1-3 years.

The sophisticated algorithms analyze seismic data for as-yet hidden patterns in the period leading to eruptions. An energy burst for four hours is one signal which usually heralds a coming explosion.

Pre-eruption patterns are then used for teaching a computer model. The model was also tested to see if it can anticipate eruptions for which it wasn't programmed. The model is meant to learn continuously with the experience it gains. Every new event from which the machine learns improves its capacity to make accurate forecasts.

The study also focused on optimizing alerts to have the most effective system. A highly sensitive system raises more alerts than needed, while the converse has a bar that is set too high, which will likely miss some eruption events. The researchers settled on a setting that provides an alert every time an eruption is likely to exceed 8.5%. At this threshold, an alert raised that lasts around five days will have roughly one out of 12 chances an eruption will occur.

If this alert system were monitoring Whakaari, it would have raised the alarm in four out of the most recent five major explosions of that volcano. For the deadly Whakaari December 2019 eruption, it would have given a 16-hour alert.

The researchers are confident that eruptions equal to or even more massive than the 2019 Whakaari explosion will be detectable by the new system. The downside to its sensitivity is that if action is taken on all its alerts, the government will have to close off the island from visitors roughly a month per year.

Currently, the new system is already operating for five months, running continuously 24 hours per day, seven days per week. It is being integrated with existing protocols to strengthen the network and provide more accurate warnings from volcanoes in New Zealand.

The researchers are planning to develop the same system for other active New Zealand volcanoes, such as Mount Ruapehu and Mount Tongariro. These sites attract visitors by the tens of thousands every year. It could then be used for other volcanoes in other countries. The software and data of this system are available to everyone because of its immense value.

Even if volcanoes seem to have predictable behaviors, future eruptions can still be unpredictable. It is always possible that seismic precursors are not obvious, so that alert systems may not be able to anticipate events. Similar methods can be applied for other volcanoes to make them predictable, as long as enough data is available for training models.