Tonga’s volcanic eruption could cause unusual weather for the rest of the decade

The Conversation
June 3, 2024 

Hunga Tonga Volcano Eruptions (NASA Worldview)

Hunga Tonga-Hunga Ha’apai (Hunga Tonga for short) erupted on January 15 2022 in the Pacific Kingdom of Tonga. It created a tsunami which triggered warnings across the entire Pacific basin, and sent sound waves around the globe multiple times.

A new study published in the Journal of Climate explores the climate impacts of this eruption.

Our findings show the volcano can explain last year’s extraordinarily large ozone hole, as well as the much wetter than expected summer of 2024.

The eruption could have lingering effects on our winter weather for years to come.
A cooling smoke cloud

Usually, the smoke of a volcano – and in particular the sulphur dioxide contained inside the smoke cloud – ultimately leads to a cooling of Earth’s surface for a short period.

This is because the sulphur dioxide transforms into sulphate aerosols, which send sunlight back into space before it reaches the surface. This shading effect means the surface cools down for a while, until the sulphate falls back down to the surface or gets rained out.

This is not what happened for Hunga Tonga.

Because it was an underwater volcano, Hunga Tonga produced little smoke, but a lot of water vapour: 100–150 million tonnes, or the equivalent of 60,000 Olympic swimming pools. The enormous heat of the eruption transformed huge amounts of sea water into steam, which then shot high into the atmosphere with the force of the eruption.



Animation of the Hunga Tonga eruption recorded on January 15 2022 by Japan’s Himawari-8 weather satellite. The plume is just under 500km across.

Japan Meteorological Agency, CC BY

All that water ended up in the stratosphere: a layer of the atmosphere between about 15 and 40 kilometres above the surface, which produces neither clouds nor rain because it is too dry.

Water vapour in the stratosphere has two main effects. One, it helps in the chemical reactions which destroy the ozone layer, and two, it is a very potent greenhouse gas.

There is no precedent in our observations of volcanic eruptions to know what all that water would do to our climate, and for how long. This is because the only way to measure water vapor in the entire stratosphere is via satellites. These only exist since 1979, and there hasn’t been an eruption similar to Hunga Tonga in that time.

Follow the vapor

Experts in stratospheric science around the world started examining satellite observations from the first day of the eruption. Some studies focused on the more traditional effects of volcanic eruptions, such as the amount of sulphate aerosols and their evolution after the eruption, some concentrated on the possible effects of the water vapour, and some included both.

But nobody really knew how the water vapor in the stratosphere would behave. How long will it remain in the stratosphere? Where will it go? And, most importantly, what does this mean for the climate while the water vapour is still there?

Those were exactly the questions we set off to answer.

We wanted to find out about the future, and unfortunately it is impossible to measure that. This is why we turned to climate models, which are specifically made to look into the future.

We did two simulations with the same climate model. In one, we assumed no volcano erupted, while in the other one we manually added the 60,000 Olympic swimming pools worth of water vapor to the stratosphere. Then, we compared the two simulations, knowing that any differences must be due to the added water vapor.


The ash plume from the Hunga Tonga eruption in an image taken by an astronaut on January 16 2022 from the International Space Station. NASA

What did we find out?

The large ozone hole from August to December 2023 was at least in part due to Hunga Tonga. Our simulations predicted that ozone hole almost two years in advance.

Notably, this was the only year we would expect any influence of the volcanic eruption on the ozone hole. By then, the water vapour had just enough time to reach the polar stratosphere over Antarctica, and during any later years there will not be enough water vapour left to enlarge the ozone hole.

As the ozone hole lasted until late December, with it came a positive phase of the Southern Annular Mode during the summer of 2024. For Australia this meant a higher chance of a wet summer, which was exactly opposite what most people expected with the declared El Niño. Again, our model predicted this two years ahead.

In terms of global mean temperatures, which are a measure of how much climate change we are experiencing, the impact of Hunga Tonga is very small, only about 0.015 degrees Celsius. (This was independently confirmed by another study.) This means that the incredibly high temperatures we have measured for about a year now cannot be attributed to the Hunga Tonga eruption.

Disruption for the rest of the decade

But there are some surprising, lasting impacts in some regions of the planet.

For the northern half of Australia, our model predicts colder and wetter than usual winters up to about 2029. For North America, it predicts warmer than usual winters, while for Scandinavia, it again predicts colder than usual winters.

The volcano seems to change the way some waves travel through the atmosphere. And atmospheric waves are responsible for highs and lows, which directly influence our weather.

It is important here to clarify that this is only one study, and one particular way of investigating what impact the Hunga Tonga eruption might have on our weather and climate. Like any other climate model, ours is not perfect.

We also didn’t include any other effects, such as the El Niño–La Niña cycle. But we hope that our study will stir scientific interest to try and understand what such a large amount of water vapour in the stratosphere might mean for our climate.

Whether it is to confirm or contradict our findings, that remains to be seen – we welcome either outcome.

Martin Jucker, Lecturer in Atmospheric Dynamics, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Island Obliterated: Dramatic Changes at Hunga Tonga-Hunga Ha’apai

By ADAM VOILAND, NASA EARTH OBSERVATORY JANUARY 25, 2022

April 10, 2021

NASA scientists have been closely watching the evolution of the volcanic island near Tonga since 2015.

When a volcano in the South Pacific Kingdom of Tonga began erupting in late-December 2021 and then violently exploded in mid-January 2022, NASA scientist Jim Garvin and colleagues were unusually well positioned to study the events. Ever since new land rose above the water surface in 2015 and joined two existing islands, Garvin and an international team of researchers have been monitoring changes there. The team used a combination of satellite observations and surface-based geophysical surveys to track the evolution of the rapidly changing piece of Earth.

The digital elevation maps above and below show the dramatic changes at Hunga Tonga-Hunga Ha‘apai, the uppermost part of a large underwater volcano. It rises 1.8 kilometers (1.1 miles) from the seafloor, stretches 20 kilometers (12 miles) across, and is topped by a submarine caldera 5 kilometers in diameter. The island is part of the rim of the Hunga Caldera and was the only part of the edifice that stood above water.

Now all of the new land is gone, along with large chunks of the two older islands.

January 17, 2022

“This is a preliminary estimate, but we think the amount of energy released by the eruption was equivalent to somewhere between 4 to 18 megatons of TNT,” said Garvin, chief scientist at NASA’s Goddard Space Flight Center. “That number is based on how much was removed, how resistant the rock was, and how high the eruption cloud was blown into the atmosphere at a range of velocities.” The blast released hundreds of times the equivalent mechanical energy of the Hiroshima nuclear explosion. For comparison, scientists estimate Mount St. Helens exploded in 1980 with 24 megatons and Krakatoa burst in 1883 with 200 megatons of energy.

Garvin and NASA colleague Dan Slayback worked with several researchers to develop detailed maps of Hunga Tonga-Hunga Ha‘apai above and below the water line. They used high-resolution radar from the Canadian Space Agency’s RADARSAT Constellation Mission, optical observations from the commercial satellite company Maxar, and altimetry from NASA’s ICESat-2 mission. They also used sonar-based bathymetry data collected by the Schmidt Ocean Institute, in partnership with NASA and Columbia University.

For the past six years, researchers from NASA, Columbia, the Tongan Geological Service, and the Sea Education Association worked together to determine how the young terrain was eroding due to the ongoing churn of waves and occasional battering by tropical cyclones. They also noted how wildlife—various types of shrubs, grasses, insects, and birds—had moved from the lush ecosystems of Hunga Tonga and Hunga Ha‘apai and colonized the more barren landscapes of the newer land.

October 11, 2019

Things changed dramatically in January. For the first few weeks of 2022, the volcanic activity seemed typical enough, with intermittent, small explosions of tephra, ash, steam, and other volcanic gases as magma and seawater interacted at a vent near the middle of the island. The ongoing Surtseyan eruptions were reshaping the landscape and enlarging the island by adding new deposits of ash and tuff to the growing volcanic cone.

“By early January, our data showed the island had expanded by about 60 percent compared to before the December activity started,” said Garvin. “The whole island had been completely covered by a tenth of cubic kilometer of new ash. All of this was pretty normal, expected behavior, and very exciting to our team.”

But on January 13-14, an unusually powerful set of blasts sent ash surging into the stratosphere. Then explosions on January 15 launched material as high as 40 kilometers (25 miles) in altitude and possibly as high as 50 kilometers, blanketing nearby islands with ash and triggering destructive tsunami waves. An astronaut aboard the International Space Station took this photo of ash over the South Pacific.

January 16, 2022

Most Surtseyan style eruptions involve a relatively small amount of water coming into contact with magma. “If there’s just a little water trickling into the magma, it’s like water hitting a hot frying pan. You get a flash of steam and the water burns burn off quickly,” explained Garvin. “What happened on the 15th was really different. We don’t know why — because we don’t have any seismometers on Hunga Tonga-Hunga Ha‘apai — but something must have weakened the hard rock in the foundation and caused a partial collapse of the caldera’s northern rim. Think of that as the bottom of the pan dropping out, allowing huge amounts of water to rush into an underground magma chamber at very high temperature.”

The temperature or magma usually exceeds 1000 degrees Celsius; seawater is closer to 20°C. The mixing of the two can be incredibly explosive, particularly in the confined space of a magma chamber. “This was not your standard Surtseyan eruption because of the large amount of water that had to be involved,” said Garvin. “In fact, some of my colleagues in volcanology think this type of event deserves its own designation. For now, we’re unofficially calling it an ‘ultra Surtseyan’ eruption.”

For a geologist like Garvin, watching the birth and evolution of a “Surtseyan island” like this is fascinating, partly because there have not been many other modern examples. Aside from Surtsey—which formed near Iceland in 1963 to 1967 and still exists more than a half-century later—most new Surtseyan islands get eroded away within a few months or years.

What also interests Garvin about these islands is what they may teach us about Mars. “Small volcanic islands, freshly made, evolving rapidly, are windows in the role of surface waters on Mars and how they may have affected similar small volcanic landforms,” he said. “We actually see fields of similar-looking features on Mars in several regions.”

NASA Earth Observatory images by Joshua Stevens, using elevation data courtesy of Dan Slayback/NASA/GSFC. Astronaut photograph ISS066-E-117965 was acquired on January 16, 2022, with a Nikon D5 digital camera using a focal length of 50 millimeters. NASA ground photo by Dan Slayback.

Tonga in need of 'sustained support' after devastating volcanic eruption


Tongans said they were determined to rebuild their battered homeland in the wake of last week's devastating eruption and tsunami as a massive clean up continued Saturday in the Pacific kingdom

.

© Marian Kupu/Broadcom Broadcasting FM87.5 via REUTERS

The powerful eruption of the Hunga-Tonga-Hunga-Ha'apai volcano last Saturday triggered a tsunami that crashed across the Tongan archipelago, affecting more than 80 percent of the population, according to the United Nations.

Tongan journalist Marian Kupu said most locals are adamant on remaining as the huge recovery efforts began.

"We want to stay here in our country because this is what identifies us as Tongans. We want to rebuild our country and unite and move on," Kupu told AFP.

Toxic ash polluted drinking water supplies, crops were destroyed and at least two villages have been completely wiped out.

An estimated one cubic kilometre of material blasted from the volcano, and experts expect Hunga-Tonga-Hunga-Ha'apai to remain active "for weeks to months".

"Tonga's people are going to need sustained support responding to a disaster of this scale," Sione Hufanga, the United Nations Coordination Specialist in Tonga said.

"The people of Tonga are still overwhelmed with the magnitude of the disaster."

Tonga ranks third on the World Risk Report, which measures countries on their susceptibility to experiencing natural disasters.

But, despite the risk, Kupu said most Tongans wanted to stay.

"It's this feeling of pride that we have here, that we don't want to leave the country we were born and raised in," she said.

One survivor from the island of Atata, which was flattened by the tsunami, told her he would return to the island even after the devastation, she added.

"He explained he wished to go back because his parents are buried there, he was born there and his life is there.

"He wished the government or anybody would help rebuild his little island so he could go back."

'Unprecedented disaster'

The New Zealand and Australian defence forces have started delivering urgent relief supplies, particularly water, to Tonga but an Australian minister said fears of unleashing a "Covid crisis" were complicating aid efforts.

Tonga is Covid-free and has strict border control policies, requiring contactless delivery of aid, and a three week quarantine period for any aid personnel who wish to enter the country.

"It's a very, very difficult time for the people of Tonga," Australia's international development minister Zed Seselja said, but added: "We respect absolutely the desire of the Tongan government not to add a Covid crisis to a humanitarian crisis caused by a tsunami."

Meanwhile a third New Zealand navy vessel carrying helicopters, water, tarpaulins, milk powder and engineering equipment is on its way to Tonga and is expected to arrive early next week.

Defence Minister Peeni Henare said all deliveries will be contactless in accordance with Tonga's Covid-19 protocols.

The Tongan government has called the dual eruption-tsunami "an unprecedented disaster" and declared a nearly one-month national emergency.

The eruption broke a vital undersea communications cable linking Tonga with the rest of the world, and it is expected to be at least a month before all communication services are fully restored.

In the meantime partial communications has been established, although mobile network provider Digicel said the high number of calls to the island was producing delays.

(AFP)

'Proud' Tongans determined to rebuild battered homeland after eruption



Fri, January 21, 2022

Tongans said they were determined to rebuild their battered homeland in the wake of last week's devastating eruption and tsunami as a massive clean up continued Saturday in the Pacific kingdom.

The powerful eruption of the Hunga-Tonga-Hunga-Ha'apai volcano last Saturday triggered a tsunami that crashed across the Tongan archipelago, affecting more than 80 percent of the population, according to the United Nations.

Tongan journalist Marian Kupu said most locals are adamant on remaining as the huge recovery efforts began.

"We want to stay here in our country because this is what identifies us as Tongans. We want to rebuild our country and unite and move on," Kupu told AFP.

Toxic ash polluted drinking water supplies, crops were destroyed and at least two villages have been completely wiped out.

An estimated one cubic kilometre of material blasted from the volcano, and experts expect Hunga-Tonga-Hunga-Ha'apai to remain active "for weeks to months".

"Tonga's people are going to need sustained support responding to a disaster of this scale," Sione Hufanga, the United Nations Coordination Specialist in Tonga said.

"The people of Tonga are still overwhelmed with the magnitude of the disaster."

Tonga ranks third on the World Risk Report, which measures countries on their susceptibility to experiencing natural disasters.

But, despite the risk, Kupu said most Tongans wanted to stay.

"It's this feeling of pride that we have here, that we don't want to leave the country we were born and raised in," she said.

One survivor from the island of Atata, which was flattened by the tsunami, told her he would return to the island even after the devastation, she added.

"He explained he wished to go back because his parents are buried there, he was born there and his life is there.

"He wished the government or anybody would help rebuild his little island so he could go back."

- 'Unprecedented disaster' -

The New Zealand and Australian defence forces have started delivering urgent relief supplies, particularly water, to Tonga but an Australian minister said fears of unleashing a "Covid crisis" were complicating aid efforts.

Tonga is Covid-free and has strict border control policies, requiring contactless delivery of aid, and a three week quarantine period for any aid personnel who wish to enter the country.

"It's a very, very difficult time for the people of Tonga," Australia's international development minister Zed Seselja said, but added: "We respect absolutely the desire of the Tongan government not to add a Covid crisis to a humanitarian crisis caused by a tsunami."

Meanwhile a third New Zealand navy vessel carrying helicopters, water, tarpaulins, milk powder and engineering equipment is on its way to Tonga and is expected to arrive early next week.

Defence Minister Peeni Henare said all deliveries will be contactless in accordance with Tonga's Covid-19 protocols.

The Tongan government has called the dual eruption-tsunami "an unprecedented disaster" and declared a nearly one-month national emergency.

The eruption broke a vital undersea communications cable linking Tonga with the rest of the world, and it is expected to be at least a month before all communication services are fully restored.

In the meantime partial communications has been established, although mobile network provider Digicel said the high number of calls to the island was producing delays.

cf/al/oho

Tonga's Olympic Flagbearer Raising Funds to Help Islands After Volcano Eruption, Tsunami

The tsunami wiped off several small settlements in outlying islands off the face of the map

Published January 20, 2022

AP Photo/Getty Images
Left: Photo of damage caused by a tsunami that struck Tonga. Right: Pita Taufatofua.

Pita Taufatofua, known as the "Shirtless Tongan" carrying Tonga's flag at the Olympics, has established a GoFundMe page to help rebuild areas devastated by a tsunami following a volcanic eruption.

Taufatofua said that though the funds will be used to work on long-term projects to rebuild, they're also using funds to address immediate needs such as food and fuel.

As of Thursday evening, the "Tonga Tsunami relief by Pita Taufatofua" verified GoFundMe page has raised over $580,000 Australian dollars (over $400,000 U.S. dollars).

At least three people have been confirmed killed after the volcanic eruption 40 miles north of Tonga’s capital, Nuku’alofa, and the tsunami that followed. Several small settlements in outlying islands were wiped off the face of the map, according to the Red Cross and official reports, necessitating the evacuation of several hundred residents.


TONGAJAN 18
Despite Huge Volcano Blast, Tonga Avoids Widespread Disaster

TSUNAMIJAN 15
Pacific Tsunami Threat Recedes, Volcano Ash Hinders Response

"In preparation and through the recovery efforts we are seeking your donations to help our island Kingdom," Taufatofua wrote on the page, adding that though he is training in Australia, he was mobilizing "all the assistance I can to send to our beloved Tonga."

As the massive undersea Hunga Tonga Hunga Ha’apai volcano erupted on Saturday, Tongans from around the world gazed on as their relatives live streamed images of billowing clouds of ash, gas and steam emerging from beneath the depths.

Then darkness.

The eruption severed Tonga's single fiber-optic cable, rendering the entire Pacific archipelago offline and unable to communicate with the rest of the world — and leaving their loved ones terrified about what might have happened.

“It was absolutely crazy,” said Koniseti Liutai, a Tongan who lives in Australia.

“We were talking with family and relatives, because they were excitedly showing us the volcano's activities, then we heard the explosion and the big bang and everything went dark,” he said. “Then the next information we got was the tsunami warning and then the tsunami hitting; we were all absolutely fearing the worst.”

It wasn't only family and friends who could not get through. Huge ash clouds made backup communication by satellite phone next to impossible, and world leaders were not even able to get in touch with their Tongan counterparts to see what help they needed.

As the ash cleared, satellite communication improved and Tonga's telecoms operator, Digicel, said it had been able to restore international call services to some areas late Wednesday.

With the resumption of some communications, more photos have begun to emerge of the destruction, showing the once-verdant islands turned a charcoal black by a thick coating of volcanic dust.

Coastlines are strewn with debris, while people work to clean streets and walkways.

The 2-centimeter (0.78 inch) layer of ash that rendered the runway at Fua’amotu International Airport unusable has now been cleared, and the first flights carrying fresh water and other aid arrived Thursday.

A repair ship is being sent from Papua New Guinea to work on the undersea cable, but it will take some time to get to Tonga and the company in charge estimates it could take longer than a month to repair the line.

Given that the cable runs right through the volcanic zone, any new volcanic activity could completely scupper even that timeline.
AP/NBC

Fisherman recalls racing tsunami, raining rocks after Tongan volcano erupted

Smoke and ash billowing from the eruption of the Hunga Tonga-Hunga Ha'apai volcano on Jan 14, 2022. PHOTO: REUTERS/TONGA GEOLOGICAL SERVICES

SYDNEY (REUTERS) - Mr Branko Sugar and his son were spearfishing on an outer reef in Tonga last Saturday (Jan 15).

The air smelt of sulphur, as it had done for weeks, from the nearby active volcano, but he noticed the ash cloud from the crater was much higher.

As the 61-year-old stowed away his spearfishing gear, the first of four loud volcanic explosions rocked the tranquil South Pacific, sending a giant wave towards his boat.


"We stopped the boat and just looked. Then we saw the wave coming towards us. The biggest wave I've ever seen," Mr Sugar told Reuters via telephone from Tonga on Friday where communications are still only being restored.

Mr Sugar turned his boat, a 400-horsepower 27-foot (8m) World Cat catamaran, and accelerated towards deep water near Eueiki Island.

"That's what saved us, the power of the boat," he said. "I shouldn't be alive."

As he raced for safety, Mr Sugar telephoned his home on Tonga's main island Tongatapu to warn of the approaching tsunami, but nobody answered.

"The wave came past us and hit the main island, and then we knew we'd managed to get away. But then the rocks started raining. It was raining stones," he recalled.

In minutes, the Pacific blue sky turned to total darkness, ash enveloped everything and a storm seemed to whip up, lashing the boat with wind and waves.

A 12-mile (19km) trip home took three hours in the darkness before they reached the harbour.

"There were wrecked boats everywhere. Upside-down boats, sunken boats. We didn't know where to go," Mr Sugar said.

"And when we finally stopped, then we couldn't find our cars - they'd all been swept away. It was one thing after another. When we finally found them, I couldn't drive, I was blind from rocks pounding my eyes for hours driving the boat."

The Hunga Tonga-Hunga Ha'apai volcano eruption triggered tsunami that destroyed villages, resorts and many buildings and knocked out communications for the nation of about 105,000 people. It also sent shockwaves and tsunami across the Pacific.

Three people have been reported killed, say Tongan authorities.

Nasa's Goddard Space Flight Centre has said the force of the eruption was estimated to be the equivalent of five to 10 megatons of TNT, or more than 500 times that of the nuclear bomb the United States dropped on the Japanese city of Hiroshima at the end of World War II.

The volcanic explosion in Tonga destroyed an island—and created many mysteries

Maya Wei-Haas

For many years, the Hunga Tonga-Hunga Ha'apai volcano poked above the waves as a pair of narrow rocky isles, one named Hunga Tong and the other Hunga Ha'apai. An eruption in 2014 built up a third island that later connected the trio into one landmass. And when the volcano awoke in December, the uninhabited island at the peak's tip slowly grew as bits of volcanic rock and ash built up new land.

 

© Provided by National Geographic

Then came the catastrophic eruption on January 15. As seen in satellite images, only two tiny outcrops of rock now betray the beast lurking beneath the waves. But whether it happens in weeks or years, the volcano will rise again.

This cycle of destruction and rebirth is the lifeblood of volcanoes like Hunga Tonga-Hunga Ha'apai, which is just one of many that dot the Kingdom of Tonga. Still, the tremendous energy of this latest explosion, which NASA estimated to be equivalent to five to six million tons of TNT, is unlike any seen in recent decades. The eruption sent a tsunami racing across the Pacific Ocean. It unleashed a sonic boom that zipped around the world twice. It sent a plume of ash and gas shooting into the stratosphere some 19 miles high, with some parts reaching as far as 34 miles up. And perhaps most remarkable, all these effects came from only an hour or so of volcanic fury.

© Provided by National Geographic

"Everything so far about this eruption is off-the-scale weird," says Janine Krippner, a volcanologist with Smithsonian's Global Volcanism Program.

© Photograph by New Zealand Defense Force via Getty Images A blanket of ash has dulled the usually vibrant plantlife across the string of tropical islands, as shown in this January 17 image of Nomuka, where the tsunami caused extensive damage.

Scientists are now racing to work out the cause behind this week’s intense outburst and the surprisingly widespread tsunamis that followed. Some clues to what set the stage for such a powerful explosion may come from the chemistry of rocks that cooled from lava in past eruptions. In a new study published in the journal Lithos, scientists found key differences between the erupted material of small and large blasts—and now they are curious what the chemistry of this latest event might reveal.

Understanding the spark that ignited Hunga Tonga-Hunga Ha'apai’s recent explosive event could help reduce future risks. For now, however, the biggest concern is for the people of Tonga, and whether there could be more volcanic outbursts on the horizon. Almost all of the volcano is now beneath the ocean surface, hidden from satellite view, and there's no equipment on the ground to help track subterranean shifts of molten rock

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© Photograph by Japan Meteorology Agency via AP Multiple satellites captured the volcano’s tremendous blast as a billowing plume of ash and gas shot into the stratosphere. The eruption is shown here in an image taken by Himawari-8, a Japanese weather satellite.

"If we can't detect what is happening in the magma system, we have no idea what might happen next," Krippner says.

An underwater giant

While Hunga Tonga-Hunga Ha'apai has erupted many times in the past, scientists only recently realized how large these eruptions could be. Mostly submerged underwater, the volcano is not easy to study.

"No one had actually done any work on the rocks," says Simon Barker, a volcanologist at Victoria University of Wellington in New Zealand and an author of the new Lithos study documenting the volcano's history.

Barker and his colleagues chartered a boat in 2015 to camp for several nights on the volcanic island’s rubbly landscape. As they surveyed the region and collected samples of rock, the team spotted small cones from recent eruptions dotting the seafloor around the primary peak. They also discovered thick layers of fragmented lava rocks and ash, known as pyroclastic flows, from two monstrous eruptions that they later dated to around 900 and 1,800 years old.

"We saw there was a lot more complexity to the history of the volcano," Barker says.

The chemistry of erupted material might help untangle what made this eruption so powerful, explains Marco Brenna, a volcanologist at the University of Otago in New Zealand and an author of the new Lithos study.

As a magma system cools, crystals of different minerals form at different times, which changes the chemistry of the dwindling molten rock. The crystals preserve these changes as they grow, a little like tree rings.

Brenna and his colleagues analyzed the rings of crystals in the rocks that erupted during the two large blasts 900 and 1,800 years ago. Their work suggests that before the volcano unleashed these eruptions, fresh magma was rapidly injected into the chamber—a commonly proposed trigger for many volcanic eruptions. But the rocks from more moderate explosions in 2008 and 2015 lacked these rings, pointing to a constant but slow influx of magma, Brenna says.

Scientists are now hoping to study the chemistry of the freshly erupted rock to see what it can tell us about this latest event. "It'll be interesting to see what the crystals are recording," Brenna says.

While these subterranean processes may be driving part of the explosivity, water also likely had a hand in this weekend's blasts, says Geoff Kilgour, a volcanologist with New Zealand's GNS Science who was not part of the study team. Water can supercharge the power of a volcanic explosion, but it remains unclear exactly how it would have sparked the astounding boom from Hunga Tonga-Hunga Ha'apai.

Perhaps, Kilgour suggests, the recent explosion had just the right mix of magma and water; an excess of either one would have generated a more moderate blast. "It may be that we've gotten to this Goldilocks zone," he says.
Airblast tsunami?

This latest eruption is layering on even more intrigue because its mighty boom, while energetic, ejected surprisingly little material. Ash from the volcano's past large eruptions can be found on the nearby island of Tongatapu, and that layer is 10 times thicker than the new layer deposited there by the recent event, Barker says.

Some scientists now speculate that the enormous, short-lived burst of energy may have helped stir up the unusually large tsunami waves that followed the eruption.

Tsunamis usually radiate from a sudden underwater shift, like a submarine landslide down a volcano's flanks or rapid movement of the land in an earthquake. Yet after Hunga Tonga-Hunga Ha'apai erupted, waves appeared in some places, such as the Caribbean, far earlier than would be expected of a classic tsunami.

The later tsunami waves that crashed on distant shores were also strange. The farther from the trigger a tsunami travels, the more its waves should diminish. While the waves that hit the islands in the Kingdom of Tonga were damaging, they weren't high enough to account for the surprisingly large waves across the ocean.

"It basically had a very low decay of tsunami size all around the Pacific, which is really, really unusual," Kilgour says. The shockwave that traveled through the air could have coupled with the sea surface, driving the expansive tsunamis. Just such a process was proposed for the 1883 explosion of Krakatoa, one of the most powerful and deadly volcanic eruptions in recorded history.

Modeling the spread and timing of the waves along with mapping changes to the volcano could help explain what drove the large tsunami. Still, Krippner says, the confusing mix of events "is going to change the way we look at this style of eruption—and that doesn't happen that often."
Trying to monitor a hidden giant

The recent event and all its oddities highlight how little is known about submarine volcanoes, says Jackie Caplan-Auerbach, a seismologist with Western Washington University. Many of these submerged giants linger in the deep ocean, and their blasts usually aren't deadly. Yet this weekend's explosion is a stark reminder of the risks of volcanoes lingering just beneath the waves.

For now, Hunga Tonga-Hunga Ha'apai seems to have fallen silent. The locals are helping each other pick through the damage and clean up the streets. While communications remain largely severed, information about the current situation is finally starting to trickle out. Three deaths have been confirmed among Tonga's residents, with two additional deaths in Peru from the tsunami.

Damage on some of the islands is severe. The homes of all 36 residents of Mango Island have been destroyed. Just two houses still stand on Fonoifua Island, and extensive damage stretches across Nomuka Island, which has a population of 239. Damage to the largest and most populous island, Tongatapu, where about 75,000 people live, was mostly focused on the western side. The Tonga Red Cross estimates a total of 1,200 "affected households."

Ash has contaminated the islands' stores of drinking water and delayed planes from landing with additional supplies. The New Zealand navy has deployed two supply ships that are scheduled to arrive on January 21.

And there's still a risk that the volcano could have more explosive blasts in store. The Tonga Geological Services relies on visual and satellite observations to track the activity of the many volcanoes across the region. But with Hunga Tonga-Hunga Ha'apai’s volcanic tip now beneath the surface, scientists have lost sight of any signs that might help understand the volcano's activity. The potential for additional activity also prevents scientists from flying nearby for a closer look.

Even when the volcano isn't actively erupting, monitoring largely submarine volcanoes is a complex task. GPS—which is frequently used to track shifts in the surface as magma moves underground—doesn't work on the seafloor. And obtaining real-time data from seismometers on the ocean floor is technologically difficult and expensive. Caplan-Auerbach says she often likens working in the oceans to doing seismology on another planet.

Instruments known as hydrophones can listen to the grumbles of submarine volcanoes as the sound travels across vast tracts of the ocean. But these are not easy to deploy in emergency situations and require connection to underwater cables for real-time data.

The situation in Tonga highlights the need for better international efforts to fund volcano monitoring around the world, Krippner says. She and other volcanologists have all stressed how well the Tonga Geological Services is handling a near-impossible task. "They don't have a huge amount of money. They don't have a huge amount of staff," Kilgour says. "But they're asked to do a huge amount."

In the days leading up to the January 15 blast, based on visual and satellite information alone, the agency persistently warned of future eruptions and a potential tsunami, instructing locals to stay away from the beaches. "Because of that, I think they saved probably thousands of lives," Barker says.

"We often learn from these really dreadful times," Caplan-Aurbach adds. Perhaps by closely studying the aftermath of this volcanic explosion, "we'll have a better sense for what's coming."

Aerial images reveal true devastation of Tongan tsunami on remote islands

Sean Seddon

METRO UK

Tuesday 18 Jan 2022 

Some of Tonga’s 170 islands are still unaccessible after a volcano eruption this weekend (Picture: New Zealand Defence Force/AFP/Maxar/Reuters)

The true death toll from the Tongan volcano and tsunami is still emerging, with distress signals detected on one remote island.

Satellite villages have revealed mass destruction after huge waves inundated communities after an eruption on Saturday.

Emergency services are still attempting to make contact with remote outcrops of the South Pacific kingdom, which is made up of 170 islands.

Humanitarian efforts are being hampered by a thick layer of ash covering the archipelago’s main airport which is preventing relief flights from landing.

The death toll stands at just two officially but with evidence of further devastation mounting, there are fears that the number could climb once the true cost is assessed.

Reconnaissance flights revealed an entire village was wiped out on Mango island and buildings had collapsed on nearby Atata island.

Curtis Tuâihalangingie, Tonga’s deputy head of mission in Australia, said: ‘People panic, people run and get injuries’.

Satellite images taken before and after the eruption of the Hunga Tonga-Hunga Ha’apai reveal its effects (Picture: Reuters)

Entire islands have been blanketed in thick layers of ash sent into the air by the eruption (Picture: Reuters)

Satelite and aerial images are being used to assess the damage to islands which can’t be reached by aid efforts (Picture: AFP)

The Royal New Zealand Air Force has been assisting with efforts in recent days (Picture: Reuters)

He described aerial images taken by the New Zealand Defence Force as ‘alarming’, adding: ‘Possibly there will be more deaths and we just pray that is not the case.’

Australia’s minister for the Pacific has pledged to help evacuate people from the low-lying, isolated islands of Ha’apai, describing conditions there as ‘very tough, we understand, with many houses being destroyed in the tsunami’.

The United Nations had earlier reported a distress signal was detected in Ha’apai, where Mango is located.

The Tongan navy previously reported the remote area was hit by waves estimated to be up to 30ft high.

Atata and Mango islands, which have a joint population of around 150, are within 45 miles of the Hunga Tonga-Hunga Ha’apai volcano.

The huge explosion, which was heard 1,430 miles way, sent shockwaves across the Pacific Ocean and blackened the sky with a colossal column of ash and smoke.
Underwater volcano eruption off Tongan coast sparks tsunami warnings

Tonga is situated in an area of high volcanic activity and the region is no stranger to natural disasters (Picture: AP)

Roads have been cut off by water and ash, further hampering aid efforts (Picture: Tea Tuur)

Buildings have been washed away after huge waves battered coastlines (Picture: Tea Tuur)

Tongan officials fear the waves caused by the volcano ‘possibly went through Atata from one end to the other’.

The UN said it hoped the airport’s runway would be operational by Wednesday and New Zealand has deployed two ships loaded with aid and workers.

With Tongan officials warning about price gouging in the face of shortages, the country is expected to set out a formal request for international aid in the coming days.

The country’s main undersea communications cable was also badly damaged during the tsunami, further cutting off the islands.

Samiuela Fonua, the chair of Tonga Cable, said there were two cuts in the undersea cable that would not be fixed until volcanic activity ceased, adding: ‘The condition of the site is still pretty messy at the moment.’

Angela Glover, a 50-year-old animal charity worker from Brighton, became the first confirmed victim after she was swept away by high waters on the island of Tongatapu.

Aid crews survey ‘extensive damage’ in Tonga as island nation remains largely cut off

Issued on: 18/01/2022 

Satellite images shows the main port facilities in Nuku'alofa, Tonga, before (L) and after (R) the main eruption of the Hunga Tonga-Hunga Ha'apai volcano, January 18, 2022. © 2022 Maxar Technologies/Handout via Reuters; photomontage by France 24

Text by: FRANCE 24

Aid agencies reported “extensive damage” in the Pacific island nation of Tonga on Tuesday following a massive underwater volcanic blast and tsunami, as the first death from the disaster was confirmed.

Early indications of the scale of the crisis on the virtually cut-off island kingdom were emerging through patchy satellite phone contact with Tonga, surveillance flights and satellite images, three days after the volcanic eruption.

The body of a British woman swept away by the tsunami had been found, her family said. At least one other person in Tonga was reported missing.

Australia and New Zealand, which scrambled Orion reconnaissance plane flights over Tonga the previous day, readied aid ships for deployment to Tonga.

The UN said a signal had been detected from a distress beacon on a low-lying island, Mango.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said surveillance flights had confirmed “substantial property damage” on Mango and another island, Fonoi.

“An active distress beacon had been detected from Mango,” OCHA agency said in an urgent report. The island is home to more than 30 people, according to Tongan census figures.

Volcanic ash and dust

OCHA also reported “extensive damage” on the western beaches of the main island Tongatapu, “with several resorts and/or houses destroyed and/or badly damaged”.

Tonga’s capital Nuku’alofa was blanketed in two centimetres of volcanic ash and dust, it said. Power had been restored to parts of the capital. Local phones systems had been restored but international communications were severed.

The capital’s waterfront, it said, was “seriously damaged with rocks and debris pushed inland from the tsunami”.

Satellite images released by the United Nations Satellite Centre showed the impact of the eruption and tsunami on the tiny island of Nomuka, one of the closest to the Hunga-Tonga-Hunga-Ha’apai volcano.

The satellite centre said of 104 structures analysed in the cloud-free area, 41 structures were identified as damaged and almost all were covered with ash.

Tonga’s airport had expected to clear volcanic ash from the capital’s runway by Monday, OCHA said.

Australia said the ash must be cleared before it can land a C-130 military plane with aid.

The human toll remains largely unknown.

‘Cling on to a tree’

The first confirmed death was Angela Glover, a 50-year-old who ran a stray animals charity and was reported missing by her husband after the tsunami hit.

“Earlier today my family was sadly informed that the body of my sister Angela has been found,” her brother Nick Eleini said after being given the news by the husband, James Glover.

“James was able to cling on to a tree for quite a long time, but Angela was unable to do so and was washed away with the dogs,” he told The Guardian newspaper.

Tonga’s worried neighbours are still scrambling to grasp the scale of the damage, which New Zealand’s leader Jacinda Ardern said was believed to be “significant”.

Australia’s HMAS Adelaide, and New Zealand’s HMNZS Wellington and HMNZS Aotearoa were deployed in case of any aid request from Tonga, which lies three days’ sailing away.

Water is expected to be a priority, New Zealand’s defence minister said Tuesday, as water sources in Tonga are at risk of being poisoned by the volcanic fallout.

France, which has territories in the South Pacific, pledged to help the people of Tonga’s “most urgent needs” in cooperation with Australia and New Zealand.

Australia’s international development minister, Zed Seselja, said a small contingent of Australian police stationed in Tonga had delivered a “pretty concerning” initial evaluation of the western beaches area.

‘Devastation’

Major aid agencies, which would usually rush in to provide emergency humanitarian relief, said they were stuck in a holding pattern, unable to contact local staff.

“From what little updates we have, the scale of the devastation could be immense—especially for outlying islands,” said Katie Greenwood, IFRC’s Pacific Head of Delegation.

Even when relief efforts get under way, they may be complicated by Covid-19 entry restrictions. Tonga only recently reported its first-ever coronavirus case.

Saturday’s volcanic blast was one the largest recorded in decades, erupting 30 kilometres (about 19 miles) into the air and depositing ash, gas and acid rain across a swathe of the Pacific.

The eruption was recorded around the world and heard as far away as Alaska, triggering a tsunami that flooded Pacific coastlines from Japan to the United States.

The massive waves even prompted an oil spill in Peru, as they rocked a ship unloading crude at a refinery near Lima. The spill left at least two kilometres of the country’s central coast dirtied with oil, Environment Minister Ruben Ramirez said on Monday.

The eruption severed an undersea communications cable between Tonga and Fiji that operators said would take up to two weeks to repair.

“We’re getting sketchy information, but it looks like the cable has been cut,” Southern Cross Cable Network’s networks director Dean Veverka told AFP.

(FRANCE 24 with AFP)

Five facts about disaster-hit Tonga


By AFP
Published January 18, 2022
Tonga volcano - Copyright AFP

The Pacific island nation of Tonga has suffered widespread damage after a huge underwater volcanic eruption and tsunami on the weekend.

The disaster has virtually cut the country off from the rest of the world as neighbours and aid organisations try to organise assistance.

Here are five facts about Tonga:

– Remote archipelago –

Tonga is made up of 169 islands in the South Pacific, spread over 800 kilometres (500 miles) in a north–south line. Only 36 of them are inhabited.

The population is around 105,000. A similar number lives overseas — mainly in New Zealand, Australia and the United States — and their remittances prop up the economy.

The capital Nuku’alofa was less than 70 kilometres from the Saturday eruption, according to the US Geological Survey, which blanketed the city with two centimetres of volcanic ash and dust.

Tonga’s remote location means it can get cut off from the world if there are problems with the undersea cable that links it to the internet through Fiji.

The latest eruption has severed that connection, reducing information from Tonga to a trickle.

The nation was previously isolated for two weeks in 2019 when a ship’s anchor cut the cable. A small, locally operated satellite service was set up to allow minimal contact with the outside world.

– Ancient monarchy –

Tonga was settled around 1,500 BC, and claims to be the only remaining indigenous monarchy in the Pacific islands.

Its monarchy can trace its history back 1,000 years. By the 13th century, the nation wielded power and influence over surrounding islands, including Samoa, nearly 900 kilometres to the east.

Various islands had royalty until 1845 when they were united under King George Tupou I, who became known as the leader of modern Tonga.

It is the only Pacific island nation that was never formally colonised. Instead, it negotiated to become a protected state under a Treaty of Friendship with Britain in 1900 while maintaining its sovereignty.

Tonga became independent in 1970.

– Political changes –

Tonga was under feudal rule until 2010, when the monarchy boosted democratic representation in the wake of rioting four years earlier that razed Nuku’alofa’s downtown area.

But a string of political scandals and perceptions of government incompetence have eroded faith in the fledgling democracy’s institutions.

Siaosi Sovaleni was appointed prime minister after an election in November in which corruption and Covid-19 were on top of the agenda.

Tonga was one of the last remaining places in the world without Covid until November last year, when it detected its first coronavirus case.

– No business, no sport, no housework on Sunday –

King Tupou I converted to Christianity after coming under the influence of missionaries.

Christianity is a vital part of Tongan life and Sundays are devoted to church, family, feasting and rest.

Businesses and shops are closed by law, modest dress is required and even in the rugby-mad isles, the no-sport Sunday is strictly observed.

– Tin Can Island –

Niuafo’ou, a small island with an underwater volcano attached, is widely known in the world of stamp collectors as Tin Can Island.

The island achieved its nickname because it has no natural anchorage, and for decades the only way for mail to arrive and leave was for a strong swimmer to take a biscuit tin out to passing ships.

According to modern legend, the practice was abandoned in 1931 when a swimmer fell victim to a shark attack.

Mail and stamps postmarked on the island pre-1931 are much sought after by collectors.

AFTER THE FLOOD 

Aliki Kraterou

17 Jan 2022

SHOCKING before and after satellite photos have revealed the full scale of the devastation caused by the catastrophic tsunami in Tonga which is even visible from space.

According to images taken around 12 hours later, the island of Hunga-Tonga-Hunga-Ha'apai has completely disappeared following the volcanic eruption.

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An image taken on December 8, compared to one taken on January 16, shows the damage caused by the eruptionCredit: UNOSAT

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A satellite image taken in April 2020 and an image taken after the volcano eruption shows the area covered in volcanic ashCredit: UNOSAT

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The island of Tongatapu has been severely damagedCredit: UNOSAT

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The volcano last erupted in 2014Credit: UNOSAT

The main island Tongatapu has been heavily affected, with water damage being visible to the northern and southern sides.

The volcano which last erupted in 2014, has also caused damage to the islands of Uoleva and Nomuka.

While Hunga-Tonga-Hunga-Ha'apai has erupted regularly over the past few decades, early data suggests the eruption was the biggest since Mount Pinatubo in the Philippines 30 years ago, New Zealand-based volcanologist Shane Cronin told Radio New Zealand.

He said: "This is an eruption best witnessed from space."

While initial reports do not suggest mass casualties, two people have been reported missing.

"Further volcanic activity cannot be ruled out," the U.N. Office for the Coordination of Humanitarian Affairs (OCHA) said in the update today.

It added that the official assessments have not been released yet as the communications have been badly hit.

Concern has been mounting for the inhabitants of two small low-lying islands- Fonoi and Mango -after a distress beacon was detected

According to the Tonga government, 36 people live on Mango and 69 on Fonoi.

It comes as the body of the missing British charity worker Angela Glover, 50, was discovered by her husband James earlier today.

Two more people have drowned at the coast of Peru after the tsunami sparked high waves.

The impact of the eruption was felt as far away as Fiji, New Zealand, the United States and Japan.

Aid workers have warned 80,000 of Tonga's residents could be affected.

Meanwhile, Australia and New Zealand have sent surveillance flights today to assess the damage.

Australia's Minister for the Pacific Zed Seselja said Australian police had visited beaches and reported significant damage with "houses thrown around".

Tonga's deputy head of mission in Australia, Curtis Tu'ihalangingie, said Tonga was concerned about the risk of aid deliveries spreading COVID-19 to the island, which is COVID-free.

"We don't want to bring in another wave - a tsunami of COVID-19," Tu'ihalangingie told Reuters by telephone.

The Haatafu Beach Resort, on the Hihifo peninsula, 13 miles west of the capital Nukualofa, was completely wiped out, the owners said on Facebook.

The family that manages the resort had run for their lives through the bush to escape the tsunami, it said. The whole western coastline has been completely destroyed along with Kanukupolu village, the resort said.

The Red Cross said it was mobilising its network to respond to what it called the worst volcanic eruption the Pacific has experienced in decades.

Alexander Matheou, the federation's Asia Pacific regional director, said water purification, providing shelter, and reuniting families were the priorities - but they had yet to establish direct contact with colleagues on the ground and were relying on estimates based on previous such disasters.

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Dramatic official aerial maps showed the eruption cloud over TongaCredit: Tonga Meteorological Services, Government of Tonga

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Smoking Hunga Tonga-Hunga Ha’apai volcano on Jan 7

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Brit charity worker Angela Glover was confirmed dead

Images reveal devastation in tsunami-hit Tonga


By AFP
Chris FOLEY

A volcano that exploded on the Pacific island nation of Tonga has almost disappeared from view, new images revealed Tuesday, with swathes of the island nation smothered in grey ash and dust or damaged by a tsunami.

Tonga has been virtually cut off from the rest of the world since Saturday’s volcanic blast — one of the largest recorded in decades.

The volcano erupted 30 kilometres (about 19 miles) into the air and deposited ash, gas and acid rain across a large area of the Pacific.

Three days after the eruption, the outside world is still scrambling to understand the scale of the disaster, using patchy satellite phone connections, surveillance flights and satellite images.

New Zealand said two people have been confirmed killed, citing Tonga police on the island. One of them is a British woman. Her family say the body was found after she was swept away by the tsunami.

Satellite images released by Maxar Technologies on Tuesday showed that where most of the volcanic structure stood above sea level a few days ago, there is now just open sea.

Only two relatively small volcanic islands were still visible above sea level after the eruption.

In fact, “what we saw above the water — that has now been destroyed — was only the tip of a volcano that had grown on the rim of the massive underwater volcano,” said Monash University vulcanologist Heather Handley.

New Zealand released aerial images taken from a surveillance flight the previous day, revealing a tree-lined coast transformed from green to grey by the volcanic fallout.

– ‘Distress beacon’ –

Wrecked buildings were visible on the foreshore alongside others that appeared intact.

Volcanic ash blanketed island fields, images from an Australian Defence Force P-8A Poseidon patrol aircraft showed.

Shipping containers had been knocked over like dominoes at a port on the main island.

Australia’s HMAS Adelaide and New Zealand’s HMNZS Wellington and HMNZS Aotearoa were ordered to be ready for a possible aid request from Tonga, which lies three-five days’ sailing away.

With water sources feared to be poisoned by volcanic fallout, the Red Cross said it was sending 2,516 water containers.

France, which has territories in the South Pacific, pledged to help the people of Tonga’s “most urgent needs”.

The UN said a signal had been detected from a distress beacon on a low-lying island, Mango.

The UN Office for the Coordination of Humanitarian Affairs said surveillance flights had confirmed “substantial property damage” on Mango, home to some 30 people, and another island, Fonoi.

The UN agency also reported “extensive damage” on the western beaches of the main island Tongatapu, “with several resorts and/or houses destroyed and/or badly damaged”.

Tonga’s capital Nuku’alofa was shrouded in two centimetres of volcanic ash and dust, it said.

Power had been restored to parts of the capital. Local phone systems had been restored but international communications were severed.

– ‘Cling on to a tree’ –

The capital’s waterfront, the UN body said, was “seriously damaged with rocks and debris pushed inland from the tsunami”.

Satellite images released by the United Nations Satellite Centre showed the impact of the eruption and tsunami on the tiny island of Nomuka, one of the closest to the Hunga-Tonga-Hunga-Ha’apai volcano.

The satellite centre said of 104 structures analysed in the cloud-free area, 41 structures were identified as damaged.

Tonga’s airport was working to remove volcanic ash from the capital’s runway. Australia said the ash must be cleared before it can land a C-130 military plane with aid.

The human toll remains largely unknown.

One of the two confirmed dead was Angela Glover, a 50-year-old who ran a stray animals charity and was reported missing by her husband after the tsunami hit.

“Earlier today my family was sadly informed that the body of my sister Angela has been found,” her brother Nick Eleini said after being given the news by the husband, James Glover.

“James was able to cling on to a tree for quite a long time, but Angela was unable to do so and was washed away with the dogs,” he told The Guardian newspaper.

No details were released about the other death.

-‘Cable has been cut’ –

Even when relief efforts get under way, they may be complicated by Covid-19 entry restrictions.

Saturday’s eruption was recorded around the world and heard as far away as Alaska, triggering a tsunami that flooded Pacific coastlines from Japan to the United States.

In Peru, authorities sealed off three beaches Monday after they were hit by an oil spill blamed on freak waves caused by the volcanic eruption in Tonga.

The blast severed an undersea communications cable between Tonga and Fiji that operators said would take up to two weeks to repair.

“We’re getting sketchy information, but it looks like the cable has been cut,” Southern Cross Cable Network’s networks director Dean Veverka told AFP.