The eruption of the Tonga volcano in January has started the year with a bang that caused devastating outcomes for the island, making it a global event amid the COVID-19 pandemic. The last explosion comparable to it was recorded nearly 140 years ago, which also caused a shock to the world.
Phys.org reported two studies by 76 scientists from 17 nations that have characterized the Tonga volcanic eruption as the biggest atmospheric explosion ever recorded since the 1883 Krakatoa eruption based on data collected that detailed the size of waves originating from the eruption. Also, it provides exceptional resolution of the evolving wavefield compared to the available data from the Krakatoa eruption.
Picture dated March 18, 2009 showing an undersea volcano eruption about 10 to 12 kilometres (six to seven miles) off the Tongatapu coast of Tonga sending plumes of steam and smoke hundreds of metres into the air.
Unprecedented Modern Geophysical Record
The eruption of Tonga volcano on Jan. 15 generated a different kind of atmospheric wave that included booms heard 6,200 10,000 kilometers) miles aware in Alaska. More so, it created the unusual appearance of tsunami-like disturbance an hour before the actual tsunami began.
Lead author Robin Matoza from UC Santa Barbara's Department of Earth Science said the atmospheric waves produced by the eruption were "unprecedented in the modern geophysical record."
The volcanic eruption produced ionospheric perturbations as seismometers across the world recorded pure seismic and air-to-ground coupled waves, WION reported. The explosion also led to an "umbrella cloud" approximately 18 miles (30 kilometers) above sea level that produced a broad range of atmospheric waves.
Moreover, the eruption destroyed nearly 50 miles (80 kilometers) of undersea cable, which caused the Pacific island nation to remain disconnected for a week. The devastating effects on Tonga hampered relief efforts as backup satellites failed due to a patchy broadband connection.
Lamb Waves Circled Earth Four Times
Scientists have access to an extraordinary array of both ground- and space-based instruments such as atmospheric pressure sensors, seismometers, hydrophones, and satellites that monitor Earth. However, they are most interested in the Lamb wave - the most dominant wave produced by the eruption.
According to BBC, Lamb waves are energetic waves in the air that propagate at the speed of sound. Named after the early 20th-century mathematician Horace Lamb, these waves can maintain their shape as they travel and so are conspicuous over a long time. Lamb waves are commonly associated with large atmospheric explosions, like nuclear detonations.
In Tonga volcanic eruption's case, it created Lamb wave pulses that circled the Earth at least four times in one direction and three times in the opposite direction. It also reached the ionosphere, rising to an altitude of about 280 miles (450 kilometers). It even reportedly lifted the clouds over the UK, which is 10,252 miles (16,500 kilometers) away from Tonga.
Atmospheric physicist Professor Giles Harrison from the University of Reading, a co-author of the study, said that the laser cloud-base recorder recorded the remarkable interconnected thing, proving that what happens to one side of the planet can propagate to the other side at the speed of sound.
RELATED ARTICLE: Tonga Volcano Eruption Was 1,200 Times More Powerful Than Hiroshima Atomic Bomb; The Most Intense Explosion in 30 Years, NASA Says
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