An Underwater Volcano Caused An Event Scientists Had Never Seen Before

The people of Tonga are used to volcanoes flaring up from time to time. The 170 small islands that make up the nation — only around 25 percent of them inhabited — are positioned in an especially seismically active part of the Pacific Ocean. The population lives in the vicinity of a dozen active submarine volcanoes, not to mention a bunch more rising on the surface.

Tonga has a tiny population, today estimated at about 108,000. Most of its people reside on Tongatapu island, which is considered to be the “main” island. It’s roughly equivalent in size to Sacramento, California.

The Hunga submarine volcano had generally been in a dormant state for about seven years, but at the end of 2021 it started to exhibit signs of sparking into life again. Some 40 miles away in the country’s capital of Nukuʻalofa, residents had begun to notice plumes of steam and ash rising from the twin uninhabited islands marking the volcano’s position. The mood on the ground initially appeared to be fairly relaxed, albeit with hints of concern.

But as December gave way to January and the new year of 2022 things seemed to have calmed down. The volcano appeared to become dormant again, and it was officially asserted as such by The Tonga Geological Services on January 11. That relief was short-lived.

And then the sea began to act strangely. Across the coastline, the tides started to pull back and whirlpools began to materialize. Something was wrong, and the people of the islands were experienced enough to know what was about to happen.

Early in the morning of January 14, 2022, at around 4.20 a.m., everything finally came to a head. An incredible explosion sounded from Hunga, shaking the ground beneath the people of Tonga’s feet. Marian Kupu, a journalist in the village of Kolovai on Tongatapu, did her best to relay to ABC News how that terrifying moment had played out.

Hunga had erupted with incredible violence, and now people across Tonga were facing the dire consequences. For one thing, a terrible tsunami had been generated, and for another, a vast quantity of ash had shot into the sky and was now descending upon the population.

Of course, it wasn’t just the people on Tongatapu who were impacted by the eruption. Over on the island of Nomuka, a woman named Sela Faitangane had been walking through the woods when she felt the blast rock her home. Her world, in an instant, was about to crumble.

Faitangane, who has two kids, needed to act fast. Together with her husband, she gathered the children and they all jumped into their car. The road was already out of action because of the flooding, but they needed to get to high ground by any means necessary.

The sky turned dark and heavy with ash, which soon began to fall upon people. The atmosphere of doom must have been totally overwhelming at this point, and that would only have got worse when Faitangane took note of the drinking-water situation. None could be found, which was a problem for everyone, but especially her youngest child.

The situation was dire all across the Tongan islands. Over on Atatā, a guy named Lisala Folau had been taking a walk when the tsunami hit. As the waves crashed over him, he did the only thing he could: he clung onto a tree for dear life. At one stage his son had called out to him, but Folau didn’t reply. He was afraid that, if he had, his son might have tried to rescue him and himself be swept away.

Elsewhere on Atatā, a woman named Elisiva Tu’ivai and her grandma were also fighting the terrible waves by holding onto trees. It wasn’t easy, and their heads would often slip beneath the gushing water. “I was scared I would die,” Tu’ivai later recalled.

Atatā was badly hit by the tsunami, but obviously it was far from the only island to experience it. Another small one called Mango Island, for example, was dramatically smashed by the waves. Almost everyone across the whole Tongan nation was affected in some way.

Many of the islanders around Tonga who’d managed to survive the night were brought to Tongatapu by boat the day after the eruption. They arrived there, in essence, having lost pretty much everything. Their homes were gone: what would they do now?

But even though the world knew something big had happened in Tonga, clear information was difficult to come by. Communication networks went down for several days following the eruption, meaning phones and the internet across the islands weren’t functioning.

A volcano expert named Sam Mitchell spoke to The Washington Post about the confusion that had reigned in the immediate aftermath of the eruption. A member of the faculty at England’s University of Bristol, all Mitchell could do was to watch from afar and to attempt to make sense of the images that were coming through. “We couldn’t see the impacts on the ground,” he said.

Obviously, the lack of news coming out of Tonga was far more upsetting for people who had relatives living on the islands. Australian resident Tricia Emberson, for instance, had family living in Tonga. She had to wait far too long to learn what their fate had been.

Emberson tried over and over again to make contact with her uncle in Tonga, but for days she just couldn’t get through to him. She supposes that she must have placed something like 40 calls over those days, which must have felt both frustrating and horribly ominous. Thankfully in the end, though, she managed to get through.

Emberson learned that her relatives had been given little more than 30 minutes to flee their position near the coast and make it to high ground. They had been on Pangaimotu Island, which quickly found itself overwhelmed by the tsunami. “The wave came,” Emberson said, “and it has just taken everything in the wash.

Teacher Dourlet had also been forced to wait it out on high ground following the tsunami. “When we came down, there was nothing left for us,” she told The Washington Post. “Not even our house, our clothes, no food.”

When the eruption came to an end, experts quickly got to work analyzing exactly what had just happened. And it didn’t take long for them to see that this eruption had been uniquely powerful. It was a record-breaking blast, larger than one that might be caused by a nuclear bomb.

Another remarkable finding that emerged in the wake of the eruption shows just how insanely powerful it had been. According to researchers, the plume that rose from the volcano generated a vast weather system.

The height that the plume of ash and other material had reached was something like 36 miles! Again, nothing like that has ever been seen before. As an expert from the U.S. Geological Survey put it, “This was on another level.”

It must have been terrifying for the people on the ground to see the things they did. The ash plume, the tsunami, and then, on top of everything, the most intense lightning storm ever recorded. Literally 50 percent of all the lightning noted on Earth at that time happened within the system created by the volcano.

Chris Vagasky was one of the researchers involved in the lightning study, and he was evidently blown away by what he found. As a senior member of the Wisconsin Environmental Mesonet and a lightning expert, he, of all people, shouldn’t have been surprised by this event — but he was. It had been genuinely unprecedented.

If nothing else, the destruction wrought by the Hunga eruption has made one thing clear: the world needs to be more prepared for the eruption of submarine volcanoes. There are plenty of them dotted around the world, and just because we can’t see them, it doesn’t mean they can’t be totally devastating. As we’ve seen in Tonga, human lives can be utterly transformed by them. But, as Monterey Bay Aquarium Research Institute scientist David Clague told The Washington Post, we’re far from being prepared for events such as this.

As the two-year anniversary of the Hunga eruption approaches, countries that are especially vulnerable to the potential effects of an underwater volcanic eruption remain in a precarious position. Experts believe that there are quite a number of submarine volcanoes that, in specific circumstances, are liable to erupt without warning.

It’s unsettling to think about the level of threat underwater volcanoes pose to populations around the world, when scientists essentially know so little about them. Only a small number of them have ever been mapped to a significant degree. And their internal workings aren’t really understood at all well.

While the equipment required for underwater volcano research is really expensive, that’s not the only issue. You also need the right people to operate all this tech, individuals who are appropriately trained. It’s complicated stuff, and using it in water — even relatively shallow parts — is really tricky.

While we may not know which specific volcanoes are especially high-risk, scientists do seem to be concerned about those based in the wider Western Pacific area. There’s a stretch there, beginning close to Japan and extending for 1,740 miles, which seems to be especially dicey.

In Europe, the submarine volcano known as Marsili is thought to be a threat. This thing stands beneath the surface of the Tyrrhenian Sea, just over a hundred miles off the shore of Naples. If it erupted, a catastrophe could be on the cards.

According to Kenna Harmony Rubin, a University of Hawaii geochemistry and volcanology professor, “Submarine volcano monitoring is in its nascency. It is, as she puts it, “well behind the state-of-the-art for volcanoes on land.” This situation is undoubtedly a massive concern, especially for people who live in at-risk areas.

And that’s the problem: given the technology necessary for submarine volcano monitoring to correctly function, huge sums of money would need to be spent. Estimates suggest such an operation would eat up $36,000 daily.

As technology advances, however, there is hope. New generations of cheap sensors should eventually come into being, which would make things an awful lot easier. In the meantime, of course, people just have to pray the submarine volcanoes near them stay quiet.

In the present, at-risk countries are having to make do with what they have. Tonga, of course, is more aware than most of the mortal threat that a submarine volcanic eruption can pose, so it’s attempting to be proactive about things.

Temperatures around volcanic vents and crevices in Tonga will be monitored by thermal infrared detectors. There will also be devices monitoring volcanic gas levels, a spike in which would indicate something was afoot.

As of September 2023 four of eight seismographs scheduled to be placed in Tonga were operational. That’s a positive step, to be sure, but there’s a problem. The lack of seismographic monitoring up until this point in time means scientists don’t really know what “normal” levels of activity actually look like!

Meanwhile, as scientists attempt to wrap their heads around this most remarkable of phenomenons and attempt to prepare for similar events in future, the people of Tonga have been trying to rebuild their lives.

Tu’ivai — the woman who alongside her grandma survived by clinging onto a tree during the tsunami — says she and her family have found getting their lives back on track really difficult. They’ve been rehoused by the government, but they’ve lost so much.