The eruption of the Tonga volcano is the most powerful in more than a century

Scientists are beginning to piece together what happened along the way January 15 eruption From the submerged volcano Honga Tonga – Hong Hapai under the sea 65 kilometers (40 miles) north of the capital of Tonga, killing at least three persons. The eruption challenged the easy explanation and turned scientists’ understanding of this type of volcano on its head.
Two new studies published Thursday in the journal Science report that volcanic eruptions sent rarely observed pressure waves around the world for six days and unleashed an unexpected type of tsunami. The massive clouds of gases, water vapor, and dust also caused strong winds from hurricanes in space, NASA said in a separate study published this week.

Early data in the aftermath of the eruption indicated that it was the largest since the 1991 eruption of Mount Pinatubo in the Philippines, but scientific studies, involving 76 scientists in 17 countries, indicated that the pressure waves it released were similar to those from the eruption of Mount Pinatubo in the Philippines. . disaster 1883 eruption of Krakatoa and 10 times larger than the one in 1980 Mount Saint Helens eruption in Skamania County, Washington.

The researchers of the scientific study wrote that the eruption of the Tonga volcano was “extraordinarily active”. They revealed that low-frequency atmospheric pressure waves, called Lamb waves, that were detected after the volcanic eruption circled the planet in one direction four times and in the opposite direction three times.

A relatively rare phenomenon, these waves travel at the speed of sound. It cannot be detected by humans and Study author Quentin Brisaud, a geophysicist, said: In the Norwegian Seismological Matrix in Oslo. Convective waves were also observed during the Cold War after atmospheric nuclear tests.

“It’s very rare. So convective waves are really associated with large-volume displacements from the air. They mostly propagate along the Earth’s surface,” said co-author Gili Asinek, senior geophysics in the Department of Seismology and Acoustics at the Royal Netherlands Meteorological Institute.

Moving across the surface of many oceans and seas, the convective pressure waves from the explosion created a fast-moving wave of scattering tsunamis.

Conventional tsunamis are usually associated with sudden changes in the ocean floor such as an earthquake. Crucially, this is what is called meteotsunamis Travel is much faster than a traditional tsunami, arriving two hours earlier than expected, and lasting longer, which could have implications for early warning systems.

Because the atmospheric pressure wave generated them, the tidal waves seemed to “jump continents,” with tsunamis recorded from the Pacific Ocean to the Atlantic Ocean, said co-author Silvio de Angelis, Professor Volcanic Geophysics in the Department of Earth, Oceanic and Environmental Sciences at the University of Liverpool in the United Kingdom.

The research also revealed that the audible sound of the volcanic eruption was detected more than 10,000 kilometers (6,000 miles) from the source in Alaska. – He heard a series of explosions. The study said the 1883 eruption of the Krakatoa volcano was heard 4,800 kilometers (2,980 miles) away, although it was less systematically reported than in Tonga.

A lithograph showing clouds flowing from the Krakatoa volcano during the catastrophic eruption of 1883 in southwestern Indonesia.

The researchers said more data is needed to understand the eruption mechanism.

One reason for such an energetic eruption – creating a 30-kilometre-high (about 19 miles) canopy cloud and a 58-kilometre (36-mile)-high plume – is thought to have been due to “the ingress of hot, gas-filled magma into the rapid transmission of intense heat”, de Angelis said via email. Between hot magma and cold water Violent explosions capable of rupturing the magma.”

space disturbance

Another study published Tuesday in Geophysical Research Lettersfound that the Tonga volcano also wreaked havoc in space, resulting in strong hurricane winds, based on data from the European Space Agency’s Ionospheric Connection Explorer or ICON mission and the European Space Agency’s Swarm satellites.
Giant clouds of gases, water vapor and dust pushed up into the sky by the volcanic eruption caused major pressure disturbances in the atmosphere, creating strong winds, according to NASA. He said in a statement. As these winds expanded upward into thinner layers of the atmosphere, they began to move faster.

“Reaching the ionosphere and the edge of space, ICON recorded wind speeds of up to 450 miles per hour — making it the strongest winds of less than 120 miles at altitude measured by the mission since its launch,” NASA said.

(From left) Satellite images from January 6 and January 18 show the impact of the volcanic eruption near Tonga.

In the ionosphere, where Earth’s atmosphere meets space, intense winds also blew electric currents, flipping the particles from their usual east-flowing electric current – called the equatorial electric current – to a westward direction for a short time, and the electric current rushing to five times its normal maximum strength .

“It is very surprising to see that electric current is largely reversed by something that happened at the surface of the Earth,” said Joanne Wu, a physicist at the University of California, Berkeley, and co-author of the Geophysical Research Letters study.

“This is something we’ve only seen previously with strong geomagnetic storms, which are a form of space weather caused by particles and radiation coming from the sun.”

said Brian Harding, a physicist at the University of California, Berkeley and lead author The eruption of the Tonga volcano was “allowing us to test the incomprehensible relationship between the lower atmosphere and space.”

“The volcano created one of the biggest upheavals in space that we’ve seen in modern times,” he added.

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