It was responsible for the largest volcanic eruption on Earth in the past 5,000 years – and now, New Zealand’s ‘super volcano’ is once again showing increasing signs of ‘volcanic unrest’.
The Volcanic Alert Level for the volcano – located just 2,400 km from Tasmania – was raised to Volcanic Alert Level 1 for the first time yesterday, making headlines around the world.
The warning raised fears of a possible eruption within a country still reeling from the devastating 2019 eruption of the White Island volcano, which killed 22 people and injured 25 horribly.
Adding to the concern is the fact that when the Taupo last erupted around AD 232, it was the largest volcanic eruption on Earth in the last 5,000 years, while the biggest eruption 26,000 years ago was the world’s most powerful volcanic eruption. past 70,000 years.
But how likely is a big eruption – and what would happen if such a catastrophe occurred?
What is happening?
The alert level was raised after 700 earthquakes were recorded in the area since May, indicating “volcanic disturbances”.
While most of these were too small to feel, the largest earthquake was a magnitude 4.5.
According to GeoNet, which provides geological hazard information for New Zealand, volcanic disturbances are “when magma or hot water and superheated steam make their way through the ground below a volcano, resulting in earthquakes, land movement and changes in hydrothermal systems”.
He noted that there have been 17 previous episodes of turbulence over the past 150 years at Taupo, and that “earthquakes and deformation could continue over the coming weeks or months.”
Should we be worried?
In a word no.
GeoNet states that the chance of an eruption of Taupo “remains very low in any one year,” even in the face of increased activity.
There is no need to panic at the moment, volcanologist Rebecca Carey from the University of Tasmania told news.com.au.
“Taupo is a fully active volcano, which is what we call a caldera volcano – it goes through phases of small eruptions followed by large eruptions on time scales of tens of thousands of years, and some of the rest periods between those events can range from thousands to tens of thousands of years .
“It was at alert level zero, but because it’s a volcano, there’s magma underneath, and when the magma moves around the magma reservoirs, and also through the Earth’s crust, the surrounding rock cracks.
“The alert level has been increased to one, which represents slightly elevated levels of seismicity due to the process of rock fracturing as the magma moves.”
She stressed that there were no other signs of disturbance, such as high temperature levels in the lake as well as volcanic gases, which could indicate a volcanic eruption.
“The biggest eruptions happen every 100,000 years or so, and the most recent violent was only 2,000 years ago, so in terms of what we’d expect from the Taupo in the next 10,000 years or so, we’d expect more -size, low-intensity eruptions rather than a caldera eruption. else,” added Dr. Carey.
“We can’t be completely sure, because magma is produced at different rates, depending on how the plates are moving in the Earth’s crust, but in order to erupt with a very large amount of magma, giant volcanic eruptions need very long storage times for the magma generated in the crust.
New Zealand has some of the best monitored volcanoes globally, and this change in alert level is likely to lead to more monitoring methods, for example, site surveys, temperature surveys, and gas surveys. But the alert has not been raised to a level that would lead to anything more.”
Memories of the White Bay Tragedy
While the White Bay tragedy is still fresh in the minds of New Zealanders, Dr. Carey emphasized that White Island and Topo were two completely different volcanoes with radically different behavioral patterns.
“With White Island it is very common for eruptions to occur with little warning, but with caldera volcanoes (like Taupo), due to the amount of magma stored at depth, we would expect to see a range of indicators rising before the volcano erupts,” she said.
“They are completely different, so we shouldn’t expect the same patterns of activities.”
What would a super volcanic eruption look like?
Dr Carey said “large and violent” supervolcanic eruptions such as the one at Taupo 26,000 years ago need timescales of “hundreds of thousands of years” to form.
She said that if a supervolcanic eruption occurred on Taupo, Australia would likely be affected by plumes of ash traveling across the ocean, which could cause planes to land.
Sadly, the story will be quite different in New Zealand, as most of the North Island is “ash-covered” and causing significant economic and social impacts, although there will likely be enough warning to evacuate nearby residents as the alert level rises.
“The important message is that this is a very distinctive feature of Topo – it’s happened in the past, as recently as 2018,” she said.
“At this time, monitoring systems are very sophisticated at picking up a lot of earthquake events, so there is nothing alarming about these earthquake disturbances.”
She added that a major eruption would not be due for thousands of years, which means that no one alive today needs to worry about the Great Taupo Incident.
Originally published when scientists first raised the alert level after discovering 700 earthquakes in New Zealand