Researchers are beginning to put together the cause of Tonga’s volcanic eruption – and what happened next. Evidence from both groups shows that when the volcano collapsed, it spewed out a mass of magma that reacted violently to the water, causing several huge explosions and very small explosions.Hunga Tonga – HungaHaʻapai volcano erupted on January 15, 2022, producing the largest atmospheric eruption in recorded history. It sent shock waves through the world and ashes.In May, Shane Cronin, a volcanologist at the University of Auckland, New Zealand, led a team through volcanoes, moderate stress on volcanic activity, and used sonar to map its formation. They found that the four-mile-long [4 km] caldera sank to a depth of more than 700 feet [200 m] below sea level to over 2,500 feet [850 m].
The cause of the massive explosion was probably the interaction between large amounts of magma and water as the eruption began, Cronin said. “You have 20 degrees of water and you have a 1,110-degree magma that comes straight,” he says. Such a large temperature difference meant that, as the water was forced to come into contact with the magma as a result of the eruption, it exploded. Each interaction pushed deeper water into the edges of the magma, said Cronin, which increased the contact area and further exploded further with the chain reaction.
The initial depth of the caldera was also not deep enough so that the water pressure did not compress the explosion, but deep enough that the magma was absorbed by a large amount of water to interact, resulting in several large eruptions and hundreds of very small eruptions. a minute. Eyewitness accounts from the day of the explosion reported “cracks and gunfire” about 90 miles [90 km] away, Cronin said. “Those are not the sounds I have heard of volcanoes before,” he said.
A separate expedition from the National Institute for Water and Atmospheric Research (NIWA) in New Zealand in Auckland went to this volcano in April, but it did not pass over the volcano. They took a sample of the ash from the bottom of the sea near the volcano, indicating that the eruption was probably followed by a spectacular flow of pyroclastic, hot streams of ash and lava flowing over the dipped sides of caldera. The scorching ashes have turned the surrounding sea into a white desert that has “wiped everything out,” said travel guide Kevin Mackay, a NIWA marine geologist.
These streams are spread underwater thousands of square miles from the eruption, ripping off submarine cables – including those that give Tonga access to the internet, which has not yet been fully restored – and powerful tsunamis that hit nearby islands, up to 18 meters in length. Under the ocean, nothing appears to have survived, although samples are still being processed to determine the degree of damage. “We don’t even think the germs live there,” Mackay said. “That’s the way we think sediment is.”
Satellite data showed a significant increase in phytoplankton in the ocean following the eruption, which consumes the nutrients released by the eruption, Seabrook said. And in the nearby hills that jumped above sea level just 15 miles [15 km] from the eruption site, life was booming, Mackay said. “We expected life to be ruined everywhere.”
Water-vapor board
Another study presented to the EGU by Philippe Heinrich at the French and Atomic Energy Commission near Paris showed that a wave of pressure from the eruption created a tsunami to the shores of the French Mediterranean, 17,000 miles [17,000 km], and a few inches above sea level. the ascent is recorded. Luis Millán at NASA’s Jet Propulsion Laboratory in Pasadena, California, also discovered that the explosion had released a radius of 53 miles [53 km], which plunged into the stratosphere. This metal, now orbiting the earth, increases the water vapor in the stratosphere by 146 trillion (146 trillion grams), or 10%, and will likely remain in the atmosphere for at least a year. “We’ve never seen anything like this before in satellite worship,” said Millán.
Some studies suggest that there were ideas about what would happen. Thomas Walter at the German Research Center for Geosciences in Potsdam says the study of seismology points to a possible collapse of part of the caldera wall in the hours before the event. He says: “It is a very weak point. “But it could indicate that we are starting to fall and then there is an explosion.”
Cronin admits that there may be some warning. A satellite imagery shows a portion of the northern slope of the volcano falling into the sea the day before the eruption. “It may indicate the early stages of the caldera fall,” he said. That could be an important tool in predicting future submarines. “If we miss the big clue that this big one is coming, obviously that is a lesson that will move us forward,” said Cronin.
Source Journal Reference: Jonathan O’Callaghan, Burst of underwater explosions powered Tonga volcano eruption, nature News (2022), doi: https://doi.org/10.1038/d41586-022-01544-y
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