In a new study, scientists have identified the exact mechanism responsible for the exceptional tsunami that quickly spread around the world after the colossal eruption of Mount Tonga earlier this year.
In a new article published in the journal Nature, an international group of scientists stated that the exceptional event was caused by acoustic-gravitational waves (AGW). They, in turn, appeared as a result of a powerful volcanic explosion.
As these waves converged with each other, energy was continuously pumped into the tsunami, which caused it to increase in size, spread much further, faster and longer.
The eruption of the Hunga Tonga-Hunga Haapai volcano on January 15, 2022 was the largest volcanic eruption of the XXI century and the largest eruption since Krakatoa in 1883. The explosion was hundreds of times more powerful than the atomic bomb that was dropped on Hiroshima.
The eruption became a source of both atmospheric disturbances and exceptionally fast-moving tsunami waves that were recorded all over the world. This puzzled scientists. “The idea that tsunamis can be caused by atmospheric waves that appeared as a result of volcanic eruptions is not new. But this is the first time that modern instruments with high measurement density have recorded it all over the world. This allowed us to finally unravel the exact mechanism of these unusual phenomena,” said Ricardo Ramaglio, co—author of the study and a fellow at the School of Earth and Environmental Sciences at Cardiff University.
AGW are very long sound waves propagating under the influence of gravity. They can cut through both the ocean depths and the atmosphere at the speed of sound. Occur as a result of volcanic eruptions or earthquakes. Given the location of the Tonga in shallow water, the interaction of energetic AGVs with the water surface was inevitable, the scientists note.