Gas Build-Up, Not Magma Interaction, Key Factor in 2022 Tonga Eruption, Scientists Suggest

Scientists have put forth a groundbreaking theory regarding the 2022 Tonga eruption, suggesting that built-up gas, rather than the interaction of magma and water, may have been the main cause. The eruption of the Hunga Tonga-Hunga Ha’apai underwater volcano in the South Pacific Ocean on January 15, 2022, resulted in the most powerful lightning storm ever recorded and the first mega-tsunami since ancient times.

Previous research indicated that the underwater eruption was a result of two merging magma chambers, but the exact trigger of the blast remained unclear. In a new study published in the Journal of Volcanology and Geothermal Research on April 21, researchers contested earlier explanations that focused on magma meeting seawater due to limitations in heat transfer and insufficient satellite evidence.

Instead, the scientists proposed that a significant buildup of gas underneath a seal inside the volcano, which ruptured unexpectedly on January 15 after a series of smaller eruptions between December 19, 2021, and January 13, 2022, was the primary factor behind the eruption. Lead author Richard Henley, an honorary professor of material physics at the Australian National University, described the event as a Plinian eruption, which is the common image that comes to mind when picturing an erupting volcano.

Henley and his team introduced a new element contributing to the intensity of Plinian eruptions, including the record-breaking Tonga event, challenging past theories that attributed the violence to magma-seawater interaction. This new perspective highlights that the immense power of the Tonga eruption was not solely dependent on its underwater location. Co-author Cornel de Ronde, a principal scientist at the Institute of Geological and Nuclear Sciences Limited in New Zealand, noted that the eruption at Hunga has provided valuable insights for the scientific community.