The violent volcanic eruption off the coast of Tonga in 2022 caused the fastest underwater currents ever recorded, a study published on Thursday has detailed.
The eruption began in a submarine volcano in December of 2021 and reached its climax nearly four weeks later on January 15, 2022. On the Volcanic Explosivity Index scale, the eruption rated at least a VEI-5.
It is the most powerful volcanic explosion ever recorded with modern-day equipment and triggered a deadly tsunami, released at least 192,000 flashes of lightning and had the force of hundreds of atomic bombs.
The submarine volcano also triggered avalanche-like flows that damaged underwater cables, which caused severe issues for the islands of Vava’u, Kifuka, and Tonatapu as it cut the islands’ connection to the outside world for weeks.
A team of researchers led by scientists from Britain’s National Oceanography Centre (NOC) used the timings and locations of the cable damage to figure out the speed of the flows, which they determined traveled at 122 kilometers per hour (75 mph) and were up to 50% faster than any other ever recorded.
"What's impressive is that Tonga's international cable lies in a seafloor valley south of the volcano, meaning the flow had enough power to go uphill over huge ridges, and then back down again,” said Emily Lane, a co-author the paper and a scientist from the National Institute of Water and Atmospheric Research, Wellington (NIWA).
"Surveys showed that Tonga's domestic cable was buried under 30 meters of material, which we sampled and confirmed as containing deposits formed by a powerful seafloor flow triggered by the eruption."
While the record breaking finding is significant, the scientists have also argued that the damage to Tonga’s subsea cables is a sign that more volcanic monitoring is needed in order to protect vital communication links.
"A huge number of the world's volcanoes lie under the ocean, yet only a handful of those are monitored,” said Isobel Yeo from the NOC. "As a result, the risk posed to coastal communities and critical infrastructure remains poorly understood, and more monitoring is urgently needed."
"Findings from this important study not only improve our understanding of one of the largest events on our planet, but are already being used by the subsea cable industry to design more resilient communications networks in volcanically active regions,” added Mike Clare, an NOC geohazards researcher.
The volcanic eruption resulted in the deaths of at least three people.