When the Hunga Tonga-Hunga Ha'apai volcano blasted gas and ash 30 miles into the atmosphere, it definitely made waves. The question is, what kind? The eruption may have been the largest in a half century — and the biggest since satellites began collecting data on such events. NASA estimated the volcanic eruption released 300 to 600 times as much energy as the atomic bomb dropped on Hiroshima.
That energy rippled above most clouds and weather. It even reached Earth’s upper atmosphere, where satellites orbit. Understanding what kinds of waves reach such great heights following a volcanic eruption is important, because it can improve satellite safety and weather predictions in space.
“The 2022 Tonga volcanic eruption caused significant perturbations across various layers of the atmosphere, even reaching altitudes where satellites orbit,” according to a the AGU Advances paper. “This event motivates us to investigate how energy transmits from the Earth's surface to the upper thermosphere.”
Volcano Impacts in Space
To learn more about what kind of waves emanated from the Hunga Tonga-Hunga Ha‘apai volcano and why they spread so far, a team of scientists tapped into satellite data and computer models. They investigated two possible culprits: Lamb waves and secondary gravity waves. Lamb waves are created by pressure and tend to hug the Earth’s surface, while secondary gravity waves originate when the initial eruption waves break apart.
Computer modeling demonstrated that the secondary gravity waves, which have faster speeds and reach higher magnitudes, best matched the satellite data. The only way the scientists could make the computer model match the satellite data was by deploying a secondary gravity wave in the simulation.
“This implies that the secondary gravity wave mechanism is likely the dominant process in generating the global-scale thermospheric waves,” according to the paper.
Read More: The Eruption in Tonga May Have Been the Largest in Half a Century
Tsunami Waves and Shockwaves
Although this study focused on waves that entered the atmosphere, the volcano produced others much closer to home.
The blast also generated a tsunami as high as 50 feet that hit many Tonga island, destroying many homes and buildings there. The tsunami crossed the Pacific to North America, where waves over three feet tall crashed into the California and Oregon coasts.
Seismometers in the Midwest detected a low-frequency shockwave. That shockwave travelled over 5,800 miles to reach Anchorage. It was also detected in Florida.
Read More: 5 of the Most Explosive Volcanic Eruptions
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Advancing Earth and Space Sciences. Were Gravity Waves or Lamb Waves Responsible for the Large-Scale Thermospheric Response to the Tonga Eruption?
Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
