Hunga volcanic eruption sparks data explosion
The giant January 15, 2022, eruption of the Hunga submarine volcano in the South Pacific, the island nation of Tonga devastated and created a variety by atmospheric wave types, including booms heard 10,000 miles away in Alaska. It also created an atmospheric pulse that created an unusual tsunami-like disturbance that arrived at the Pacific coasts earlier than the actual tsunami.
These are some of the many sightings reported by a team of 76 scientists from 17 countries who studied the eruption’s atmospheric waves, the greatest known of a volcano since the 1883 Krakatoa eruption† The team’s work, put together in an unusually short time due to significant scientific interest in the eruption, was published May 12, 2022 in the journal Science†
David Fee, director of the Wilson Alaska Technical Center at the University of Alaska’s Fairbanks Geophysical Institute, is a leading author of the research paper and one of four scientists at the center involved in the study.
The Hunga eruption, near the island of Tonga, has provided unprecedented insight into the behavior of some atmospheric waves. A dense network of barometers, infrasound 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.
“We hope we can better track volcanic eruptions and tsunamis by understanding the atmospheric waves from this eruption,” said Fee, who is also the coordinating scientist. in the Alaska Volcano Observatory section of the Geophysical Institute.
“The atmospheric waves were recorded worldwide over a wide frequency band, 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 explosions, volcanoes, earthquakes and a variety of other phenomena.”
The researchers mainly found the behavior of the eruption’s Lamb wave, a type named after its 1917 discoverer, English mathematician Horace Lamb.
The largest atmospheric explosions, such as from volcanic eruptions and nuclear tests, create Lamb waves. They can last from a few minutes to several hours.
A Lamb wave is a type of guided wave, which travels parallel to the surface of a material and also extends upwards. With the Hunga eruption, the wave traveled along the Earth’s surface, orbiting the planet four times in one direction and three times in the opposite direction — the same as observed in the 1883 eruption of Krakatoa.
“Lamb waves are rare. We have very few high-quality observations of them,” Fee said. “Understanding the Wave of the Lamb helps us better understand its source and eruption. It has been linked to the tsunami and the creation of volcanic plumes and is also likely related to the eruption’s higher-frequency infrasound and acoustic waves.”
The Lamb wave consisted of at least two pulses near Hunga, with the first having a pressure increase of seven to ten minutes, followed by a second and larger compression and subsequent long pressure decrease.
The wave also reached Earth’s ionosphere, rising at 700 mph to a height of about 280 miles, according to data from ground stations.
One major difference from the Lamb wave of the Hunga explosion compared to the wave of 1883 is the amount of data collected as a result of more than a century of advances in technology and an increase in sensors around the world, the paper said. .
Scientists noted other findings about atmospheric waves linked to the eruption, including “remarkable” long-range infrasound — sounds too low to be heard by humans. Infrasound arrived after the Lamb wave and was followed by audible sounds in some regions.
Audible sounds, the paper notes, traveled about 6,200 miles to Alaska, where they were heard in the state as repeated booms about nine hours after the eruption.
“I heard the sounds, but certainly didn’t think it was from a volcanic eruption in the South Pacific at the time,” Fee said.
The Alaska Reports are the most widely documented records of audible noise from source. That’s partly due to global population growth and advances in societal connectivity, the paper notes.
“We will study these signals for years to learn how the atmospheric waves were generated and how they spread so well across the 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, Panagiotis Vergados, Alexandra Nippress, Junghyun Park, Shahar Shani-Kadmiel, Alex Witsil, 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. Snively, 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 Che, Rodrigo De Negri, Carl W. Ebeling, 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, Mayra Oyola -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.
Other Geophysical Institute scientists involved in the research include graduate student Liam Toney, acoustic wave analysis, figure and animation production; postdoctoral researcher Alex Witsil, Acoustic Wave Analysis and Equivalent Explosive Yield Analysis; and seismo-acoustic researcher Kenneth A. Macpherson, sensor response and data quality. They are all at the Wilson Alaska Technical Center.
The Alaska Volcano Observatory, the National Science Foundation and the U.S. Defense Threat Reduction Agency funded the UAF portion of the study.
Robin S. Matoza of the University of California, Santa Barbara, is the lead author of the paper.
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