The volcanic current produced a record number of lightning bolts, which then caused reverberating explosions thousands of kilometers away. That's what geologists call triggering events and what might happen next.
Just a few weeks ago, an underground volcano identified by two insecticide-repellent islands in the Kingdom of Tonga began to erupt. The explosions appeared harmless at first, with ash-like plumes and moderate explosions rarely seen outside the archipelago.
But in the last 24 hours, a volcano called Hunga Tonga-Hunga Haapai has put the world on the brink.
After a period of calm earlier this month, its eruption activity intensified. The middle of the island disappeared from satellite imagery. Towering ash plumes began to produce record numbers of lightning bolts.
From tsunami warnings to loud bangs, Tonga's volcanic eruptions are explained
Chris Vagaski, a meteorologist and lightning application manager at Vaisala, a Finnish meteorological survey company, said: "We started processing 5,000 or 6,000 events per minute. This is 100 events per second. It's incredible. ”
Then, earlier on January 15, the volcano erupted with a big bang. The atmosphere was blown apart and a shock wave was generated from the island, radiating outward almost at the speed of sound. A sonic boom was heard in parts of New Zealand 3,300 kilometres away, and the shockwaves eventually spread to half of the uk, 25,000 kilometres away.
To my surprise, the tsunami immediately continued. It struck Tongatapu, the kingdom's main island and capital, Nuku'alofa, located dozens of miles south of the volcano. When the streets began to flood and people had to flee, communication was cut off. Although small, the tsunami crossed vast oceans and reached parts of the Pacific Northwest, causing tsunamis in Alaska, Oregon, Washington and British Columbia. Small tsunamis have also been recorded at sites in California, Mexico and South America.
Recent studies of the geological history of volcanoes have shown that such intense turbulence is a relatively rare event on human timescales. Such explosions are believed to occur every 1,000 years and last about an hour. Hopefully, the worst eruption is over. However, damage is still occurring.
"This could be a catastrophic event that looks terrible," said Janine Krippner, a volcanologist at the Smithsonian Castle's Global Volcanoes Program.
Scientists and the public alike want to know what caused such a powerful eruption and what happened next. However, since the volcano is a bit far away, the neighborhood can be difficult to see, so the information seems to be slow.
"At this point, there are more questions than answers," Krypner said. But here's what scientists know about their tectonics and geodynamics, and what they mean for the future of volcanic activity.
Pacific volcanic power
Hunga Tonga-Hunga Tonga Pai is located in the South Pacific, and many volcanoes above and below the waves are prone to violent eruptions. In past events, city-sized rafts were released, volcanoes erupted naturally, and soon new islands were built.
There are about 1500 active volcanoes in the world. Learn about the main types of volcanoes, the geological processes behind the eruptions, and their locations...
This abundant volcanic activity exists as the Pacific Plate continues to dive beneath the Australian Tectonic Plate. When the plates fall on the huge rocks of the mantle, the water inside melts and rises to the upper mantle. Adding water to these rocks will make them easier to melt. This produces magma filled with large amounts of viscous gas. This is the powerful secret of explosive eruptions.
Hunga Tonga-Hunga Tonga Pai is no exception. The land sits on a volcano more than 30 km wide, hiding a cauldron-shaped crater about 7.6 km wide from the seascape. Since 1912, it has been seen erupting with intense energy, sometimes bouncing off waves and then eroding. The eruption of 2014-15 created a stable island that soon became home to colorful plants and barn owls.
Hunga Tonga – When the Hunga Tonga began erupting again on 19 December 2021, it produced a series of explosions and 25.5 kilometres of ash eruptions, which are "not uncommon" for Bristol volcano in the UK. It was. Sam Mitchell, a university volcanologist, said that a few weeks later, enough new lava erupted to expand the island by nearly 50 percent. As the New Year approaches, the volcano seems to be calming down.
Things have changed dramatically over the past few days.
Volcanic whirlpools
As the eruptions intensified, lightning from the bushes began to cause eclipses, not only in this eruption, but also in recorded eruptions.
Volcanoes produce lightning when ash particles in volcanic eruptions collide with each other and form ice in the atmosphere to create an electric charge. Positive and negative charges separate, causing lightning. (Learn more about how volcanoes cause lightning.) ）
The lightning eruption in Tonga was initially detected by Vaisala's GLD360 network. The network uses a globally distributed wireless receiver system that can "hear" lightning during violent eruptions. television set. For the first two weeks, the system can record hundreds of flashes per day. This is not uncommon. "I think he's clearing his throat," Vargaski said.
There was no electricity anywhere on Earth last night.
Meteorologist Chris Vagasky Vaisala
But from late Friday to early Saturday, the volcano caused tens of thousands of eruptions. At one point, the Tonga volcano erupted 200,000 times per hour. By comparison, there were 340,000 eruptions in about a week of the 2018 eruption of Anak Krakatau volcano in Indonesia.
"I couldn't believe the numbers I saw," Wyski said. "This is usually not seen in volcanoes. It's a different story. There was no electricity anywhere on Earth last night. ”
From a distance, it may look spectacular, but up close, it's like the end of the world, with thunder and roaring flames. Most lightning strikes the ground and oceans, rather than isolating it from the beam. "Because there is lightning around, it's very dangerous for people living on other islands in Tonga," Wagasky said.
So why did this eruption cause a record number of eruptions?
Kathryn McKee, a volcanologist at Los Alamos National Laboratory in New Mexico, says the presence of water always increases the likelihood of lightning. When the magma mixes with shallow water, the trapped water heats up and evaporates violently, blowing the magma into millions of small fragments. The finer the particles, the more lightning is produced.
Collard Cimarelli, an experimental volcanologist at the Ludwig Maximilian University in Munich, says the heat generated by the eruption can also easily transport water vapor into a colder, higher atmosphere, where it turns into ice. This provides many additional particles for ash collisions and power generation.
However, it is unclear why volcanic eruptions trigger so many lightning strikes. "Unfortunately, these volcanoes are so far apart that there are almost no limits to the atmospheric structure near the volcanoes," Cimarelli said.