The eruption of the Hunga-Tonga volcano caused the Earth to tremble violently not too long ago. Now, in a new study, researchers have taken a closer look at the true scale of the eruption.
Volcano: Eruption Shakes Distant Parts of the World
The Hunga-Tonga eruption in the Kingdom of Tonga occurred on January 15, 2022. The atmospheric waves it released were the largest known from a volcano since the 1883 eruption of Krakatoa in Indonesia. They were so powerful that they reached all the way to Alaska.
For context, Hunga-Tonga is located about 9,650 kilometers (about 6,000 miles) from Alaska. It was an “unprecedented explosion in the instrument age,” Ken Macpherson, a scientist at the University of Alaska Fairbanks Geophysical Institute, stated in a press release. “Those pressure waves shook Alaska, 6,000 miles away, which I just think is so remarkable. And many of those were long-period waves and consequently shook Earth to a great depth”
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Important Factor for Seismic Hazards
The volcanic eruption provided scientists with valuable data, as a network of 150 barometers, infrasound sensors, and seismometers in Alaska recorded it. Most importantly, the investigations revealed key information about the interaction between the air and the ground.
Strong pressure waves generated during a volcanic eruption or explosion create changes in air pressure as they travel through the atmosphere. When these hit the ground, they exert tensile and compressive forces on the surface. This process is called air-to-ground coupling and transfers energy into the Earth’s interior.
While this might sound very theoretical at first, it can be extremely valuable in practice. The research provides important information about the speed of the waves, which is considered a crucial factor in analyzing seismic hazards. The new study on seismic velocity was recently published in the journal Seismica.
New Findings About Alaska
The subsurface material is also important in this context. Imagine you’re blowing on a bowl of Jell-O with the same force as you would on a bowl of brownie batter. Doing so, you’ll be able to watch as the Jell-O wobbles and moves, while the brownie batter hardly movies, due to its firmer material.
The massive eruption of the volcano therefore helped scientists learn more about the propagation of seismic waves in Alaska. “Just knowing those upper crustal velocities is good for seismic hazard analysis,” Macpherson said. Gaining information about air-to-ground coupling at a depth of five kilometers (about 3.1 miles) is not only unusual but also of enormous importance for science.
Sources: “Alaska Upper Crustal Velocities Revealed by Air-to-Ground Coupled Waves From the 2022 Hunga Tonga-Hunga Ha’apai Eruption” (Seismica 2025), Geophysical Institute of the University of Alaska Fairbanks
This article was originally published on futurezone.de / 4P.de and has been carefully translated.