Scientists have proposed a new theory regarding the record-shattering Tonga volcanic eruption of 2022, suggesting that the explosion may have been triggered by gas buildup rather than the previously assumed magma-water reaction.

The eruption of Hunga Tonga-Hunga Ha’apai, an underwater volcano in the South Pacific Ocean, occurred on January 15, 2022, resulting in the most intense lightning storm ever recorded and the first mega-tsunami known since antiquity. While earlier studies indicated that the eruption was fueled by the merging of two magma chambers, the exact cause of the blast remained uncertain.

In a recent study published in the Journal of Volcanology and Geothermal Research on April 21, researchers challenge the conventional belief of magma-seawater interaction as the trigger for the eruption. Instead, they propose that a significant accumulation of gas beneath a seal inside the volcano led to the explosive event on January 15, following a series of smaller eruptions between December 19, 2021, and January 13, 2022.

The formation of this seal may have resulted from a reaction between volcanic rocks and gas emanating from the volcano’s depths. The study highlights the rapid chemical reactions between sulfur dioxide and hydrogen chloride in magmatic gases, producing minerals like anhydrite, quartz, and sulfides as they ascend from the source to the surface. These minerals could obstruct flow paths and potentially seal the gas flux within the volcano.

The research challenges previous assumptions about the Tonga eruption, emphasizing the role of gas buildup rather than magma-water interaction. Satellite observations and bathymetric data were crucial in identifying the buildup of gas beneath the volcano, ultimately leading to the catastrophic eruption.

Understanding the mechanisms behind volcanic eruptions is essential for predicting and mitigating potential hazards associated with volcanic activity. The Tonga eruption serves as a reminder of the complex processes at play within Earth’s geology, shedding light on the diverse factors that can influence volcanic events.