The eruption that devastated Tonga on 15 January lasted just 11 hours, but it will take years for scientists to work out exactly what happened during the cataclysmic explosion ' and what it means for future volcanic risks. The volcano, named Hunga Tonga'Hunga Ha'apai, sent a plume of ash soaring into the upper atmosphere and triggered a tsunami that destroyed homes on Tonga's nearby islands. Reverberations from the eruption circled the globe multiple times. The extraordinary power of the blast, captured by a range of sophisticated Earth-observing satellites, is challenging ideas about the physics of eruptions. Researchers are finding it hard to explain why the volcano sent a cloud to such heights, yet emitted less ash than would be expected for an eruption of such magnitude. And the shock waves that rippled through the atmosphere and oceans are unlike anything seen in the modern scientific era. The eruption, which happened just 65 kilometres from the Tongan capital of Nuku'alofa, has been a disaster for the more than 100,000 people living in Tonga. They are working to clear away the thick layer of ash that blanketed everything, to establish clean drinking-water supplies and to recover from the crop damage, estimated to equate to nearly 39 million Tongan pa'anga (US$17 million). At least three people have died in Tonga as a result of the eruption. The crisis is being compounded by COVID-19, with Tongans facing their first wave of cases, which started after relief ships arrived from other countries....