On January 15, 2022, the submerged caldera beneath Hunga Tonga and Hunga Ha’apai islands in the South Pacific Ocean of Tonga exploded. The eruption of this volcano spewed gas and ash up to 56 miles into the Earth’s mesosphere, the highest plume from any other volcano on record. The most powerful explosion observed on Earth in modern history caused a tsunami reaching Peru and a sonic boom audible as far as Alaska.
A new study finds that the shape of the ocean floor changed dramatically when large amounts of volcanic ash, dust and glass fell into the water. For the first time, scientists have recreated what happened under the crashing waves of the Pacific Ocean.According to one paper published in science Today, all that material has flowed for tens of miles through water.
“These processes have never been observed before,” study authors say Isabelle Yeohmarine volcanologist at the UK National Marine Centre.
About 72 miles from the volcano, the eruption severed an undersea fiber optic cable. For Tongans and rescue workers, the broken cable caused serious disruptions to the island’s internet and was a major inconvenience. For scientists, the abrupt cutoff of internet traffic indicates when it provided a timestamp. something About an hour and a half after the eruption, I touched the cable.
The cut also alerted scientists to the fact that the eruption had destroyed the seafloor, but it wasn’t easy to spot. “You can’t see it from a satellite,” Yeo says. “You have to go out there and do research.” So, months after the eruption, Yeo and his colleagues sought clues from the surrounding waters and tried to piece them together.
Tongan Blanco Sugar, charter boat owner She captured the first eruption with a cell phone camera, revealing the exact time when the volcanic ejecta began falling into the water.A few months later, the ship RVs Tangaroa Sail from New Zealand to survey the seafloor and collect samples of volcanic currents.Unlike most of the seaThe seafloor around Tonga has already been mapped, and scientists were able to confirm the change in topography.
[Related: The centuries-long quest to map the seafloor’s hidden secrets]
The scene, recreated by the researchers, could fit right in with Roland Emmerich’s disaster film if it were played out on the ground. This volcano has moved as much material in a few hours as rivers around the world drain into the ocean in a year. These truly gigantic streams traveled more than 90 miles from their source and carved out canyons as high as skyscrapers.
When a volcano erupted, it spewed out huge amounts of rock, ash, glass, and gas that fell to the ground. This is the standard swamp for such eruptions, which usually produce high-velocity pyroclastic flows that threaten anything in their path. However, from Hunga Tonga to Hunga Ha’apai, the fallen chunks had nowhere to go but out to sea.
“This is that Goldilocks spot where you drop a ton of very dense material straight into the ocean and down a very steep slope that erodes the excess material,” he says. Michael Clare, a marine geologist at the National Oceanographic Center and another author. “It gets bogged down, it gets denser, and it really goes on.”
Scientists estimate that the material fanned out at 75 mph between Hunga Tonga and Hunga Ha’apai, which is at or above the speed limit on most interstate highways in the United States. It is. If correct, this would be 50% faster than any other underwater current recorded on Earth. The momentum of the earth and sand flowed back up the underwater slopes as high as mountains.
“It’s like seeing an avalanche and thinking that the next mountain is safe, but the avalanche is coming straight ahead,” says Claire.
Such underwater currents have never been observed before, researchers say. But understanding the effects of volcanoes on the ocean floor is more than just a scientific curiosity. Over the past two centuries, we’ve laid critical infrastructure beneath the surface. First telegraph cables, then telephone lines, and now the optical fibers that carry the Internet.
Trying to prepare a single cable for an eruption of this magnitude is like trying to prepare for being run over by a train, which is practically impossible. Instead, a better way to protect communications is to run more cables so that one disaster doesn’t cut them all.
[Related: Mixing volcanic ash with meteorites may have jump-started life on Earth]
In many parts of the world this is already the case. fishing accident Cables are always disconnected, but the effect is not very long lasting. For example, imagine the world repeating the same thing. Landslide caused by the 1929 earthquake We probably wouldn’t notice much if the cable were cut off Newfoundland. There are many other routes for Internet traffic running between Europe and North America.
As World map of submarine cables However, it turns out that that is not the case everywhere. In Tonga in 2022, his single cut cable has cut the archipelago almost completely from the internet. Many other islands, especially those in developing countries, are similarly vulnerable.
And these cables are also very valuable to geologists. “Without cable, we probably would still be in the dark and unaware that these kinds of events were happening on this scale,” says Clare.
