The huge eruption of Hunga volcano created an atmospheric pulse that caused an unusual tsunami-like disturbance

The huge eruption of Hunga volcano created an atmospheric pulse that caused an unusual tsunami-like disturbance

Hunga Tonga explodes

This loop video shows a series of GOES-17 satellite imagery capturing a cloud umbrella created by the Hunga Tonga-Hunga Ha’apai volcanic eruption on January 15, 2022. Crescent-shaped shock waves and numerous strikes are also striking. . Credit: NASA Earth Observatory Image by Joshua Stevens Using GOES Images courtesy of NOAA and NESDIS

The eruption of Hunga volcano provides a data eruption

The giant eruption of the Hunga submarine volcano in the South Pacific on January 15, 2022 destroyed the island nation of Tonga and created a variety of atmospheric waves, including eruptions heard at 10,000 km away. It also created an atmospheric pulse that caused an unusual tsunami-like disturbance that reached the Pacific coast earlier than the actual tsunami.

These are among the many observations made by a team of 76 scientists from 17 nations who studied the atmospheric waves of the eruption, the largest known volcano since the eruption of Krakatoa in 1883. The work of the team, written in an unusually short time due to of significant scientific interest in the explosion, published May 12, 2022, in the journal Science.

David Fee, director of the Wilson Alaska Technical Center at the Fairbanks Geophysical Institute at the University of Alaska, is the lead author of the research paper and one of four of the center’s scientists involved in the research.

Hunga Tonga Explosion NASA GOES Satellite 17

The image of the Hunga explosion is from the GOES-17 satellite of the National Oceanic and Atmospheric Administration. Credit: NOAA

The Hunga eruption, near Tonga Island, gave an unprecedented picture of the behavior of certain atmospheric waves. A dense network of barometers, ultrasonic sensors and seismometers in Alaska – operated by the Wilson Alaska Technical Center of the Geophysical Institute, the Alaska Volcano Observatory and the Alaska Earthquake Center – contributed to the data.

“Our hope is that we will be able to better monitor volcanic eruptions and tsunamis by understanding atmospheric waves from this eruption,” said Fee, who is also the coordinating scientist. at the Department of Alaska Volcanic Observatory Geophysical Institute.

“Atmospheric waves were recorded worldwide over a wide range of frequencies, and by studying this remarkable data set we will better understand the generation, propagation and recording of acoustic and atmospheric waves,” he said. “This has implications for monitoring nuclear eruptions, volcanoes, earthquakes and a variety of other phenomena.”

Hunga volcano data

The image above shows the locations of the instruments that provided the data. The red and blue motif around Hunga Volcano is a time-lapse image from a meteorological satellite showing the atmospheric disturbance created by the Lamb wave. The image below shows two months of Hunga activity. Credit: David Fee

Researchers have found the behavior of the Lamb wave of the eruption, a type named after the English mathematician Horace Lamb, who discovered it in 1917, to be particularly interesting.

Larger atmospheric eruptions, such as volcanic eruptions and nuclear tests, generate Lamb waves. They can last from minutes to several hours.

The Lamb wave is a type of directional wave, those that travel in parallel along the surface of a material and also extend upwards. With the Hunga eruption, the wave traveled across the Earth’s surface and turned the planet in one direction four times and three times in the opposite direction – the same as observed in the 1883 Krakatau eruption.

“Lamb waves are rare. “We have very few high quality observations for them,” Fee said. “By understanding the Lamb wave, we can better understand the source and the explosion. It is associated with tsunamis and volcanic eruptions and is also likely to be associated with higher frequency ultrasound and sound waves from the eruption.

Tonga Volcano Stereoscopic Observations

A NASA satellite recorded the explosion of the Hunga Tonga – Hunga Ha’apai in the South Pacific. Credit: Image by Joshua Stevens / NaSA Earth Observatory, using GOES-17 images courtesy of the National Oceanic and Atmospheric Administration and the National Environmental Satellite, Data and Information Agency

The Lamb wave consisted of at least two pulses near Hunga, with the former having a pressure increase of seven to 10 minutes followed by a second and greater compression and consequent large pressure drop.

The wave also reached the Earth ionosphere, rising at 700 mph at an altitude of about 280 miles, according to data from ground stations.

A significant difference with the Lamb wave of the Hunga eruption compared to the 1883 wave is the amount of data collected due to advances in technology for more than a century and the proliferation of sensors around the world, according to the newspaper.

Scientists have noted other findings related to atmospheric waves associated with the explosion, including the “remarkable” long-range ultrasound – which is too low-frequency to be heard by humans. The ultrasound arrived after the Lamb wave and was followed by sonic sounds in some areas.

The acoustic sounds, the newspaper notes, traveled about 6,200 miles to Alaska, where they were heard across the state as repeated eruptions about nine hours after the eruption.

“I heard the sounds, but at that moment I certainly did not think it was from a volcanic eruption in the South Pacific,” Fee said.

Alaska reports are the most remote documented audio audio reports from its source. This is due in part, the paper notes, to the increase in the world’s population and the advancement of social connectivity.

“We will study these signals for years to learn how atmospheric waves were created and how they propagated so well on Earth,” Fee said.

Reference: “Atmospheric waves and global seismoacoustic observations of the January 2022 Hunga eruption, Tonga” by Robin S. Matoza, David Fee, Jelle D. Assink, Alexandra M. Iezzi, David N. Green, Keehoon Kim, Liam Toney, Thomas Lecocq, Siddharth Krishnamoorthy, Jean-Marie Lalande, Kiwamu Nishida, Kent L. Gee, Matthew M. Haney, Hugo D. Ortiz, Quentin Brissaud, Léo Martire, Lucie Rolland, Παναγιώτης Βεργάδος, Alexandra Nippress, Junghyni-K, Shahadarel Alex Wits , Stephen Arrowsmith, Corentin Caudron, Shingo Watada, Anna B. Perttu, Benoit Taisne, Pierrick Mialle, Alexis Le Pichon, Julien Vergoz, Patrick Hupe, Philip S. Blom, Roger Waxler, Silvio De Angelis, Jonathan B. Snive Adam T. Ringler, Robert E. Anthony, Arthur D. Jolly, Geoff Kilgour, Gil Averbuch, Maurizio Ripepe, Mie Ichihara, Alejandra Arciniega-Ceballos, Elvira Astafyeva, Lars Ceranna, Sandrine Cevuard, Il-Young Ne Che, Rodrigo, Carl W. Ebel , Läslo G. Evers, Luis E. Franco-Marin, Thomas B. Gabrielson, Katrin Hafner, R. Giles Harrison, Attila Komjathy, Giorgio Lacanna, John Lyons, Kenneth A. Macpherson, Emanuele Marchetti, Kathleen F. McKee, Robert J. Mellors, Gerardo Mendo-Pérez, T. Dylan Mikesell, Edhah Munaibari, -Merced, Iseul Park, Christoph Pilger, Cristina Ramos, Mario C. Ruiz, Roberto Sabatini, Hans F. Schwaiger, Dorianne Tailpied, Carrick Talmadge, Jérôme Vidot, Jeremy Webster and David C. Wilson, May 12, 2022, Science.
DOI: 10.1126 / science.abo7063

Other scientists at the Geophysical Institute involved in the research include graduate student Liam Toney, acoustic wave analysis, figure production and animation. postdoctoral researcher Alex Witsil, acoustic wave analysis and equivalent explosive performance analysis. and seismic researcher Kenneth A. Macpherson, sensor response and data quality. Everything is with the Wilson Alaska Technical Center.

The Alaska Volcano Observatory, the National Science Foundation, and the U.S. Defense Threat Reduction Service funded the UAF section of the research.

Robin S. Matoza of the University of California, Santa Barbara is the newspaper’s lead author.

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