Hunga Volcano Eruption Provides an Explosion of Data
The gigantic January 15, 2022, eruption of the Hunga submarine volcano in the South Pacific Ocean devastated the island nation of Tonga and created a variety of atmospheric wave types, including booms heard 6,200 miles (10,000 km) away in Alaska. It also created an atmospheric pulse that caused an unusual tsunami-like disturbance that arrived at Pacific shores sooner than the actual tsunami.
Those are among the many observations reported by a team of 76 scientists from 17 nations that researched the eruption’s atmospheric waves, the largest known from a volcano since the 1883 Krakatoa eruption. The team’s work, compiled in an unusually short amount of time due to significant scientific interest in the eruption, was published on May 12, 2022, in the journal Science.
David Fee, director of the Wilson Alaska Technical Center at the University of Alaska Fairbanks Geophysical Institute, is a leading author of the research paper and among four of the center’s scientists involved in the research.
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 Geophysical Institute’s Wilson Alaska Technical Center, Alaska Volcano Observatory, and Alaska Earthquake Center — contributed to the data.
“Our hope is that we will be better able to monitor volcanic eruptions and tsunamis by understanding the atmospheric waves from this eruption,” said Fee, who is also the coordinating scientist at the Geophysical Institute’s portion of the Alaska Volcano Observatory.
“The atmospheric waves were recorded globally across a wide frequency band, and by studying this remarkable dataset we will better understand acoustic and atmospheric wave generation, propagation and recording,” he said. “This has implications for monitoring nuclear explosions, volcanoes, earthquakes and a variety of other phenomena.”
The researchers found particularly interesting the behavior of the eruption’s Lamb wave, a type named for 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 minutes to several hours.
A Lamb wave is a type of guided wave, those that travel parallel along a material’s surface and also extend upward. With the Hunga eruption, the wave traveled along Earth’s surface and circled the planet in one direction four times and in the opposite direction three times — the same as observed in the 1883 Krakatau eruption.
“Lamb waves are rare. We have very few high-quality observations of them,” Fee said. “By understanding the Lamb wave, we can better understand the source and eruption. It is linked to the tsunami and volcanic plume generation and is also likely related to the higher-frequency infrasound and acoustic waves from the eruption.”
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