Hunga Tonga-Hunga Ha'apai's eruption, which has been blamed for just six deaths, was similar in size to the Krakatoa explosion in Indonesia in 1883, according to the findings published in Science.
The Tonga explosion generated pressure waves, called Lamb waves, which travelled horizontally along Earth's surface for more than six days, according to the article.
Those Lamb waves are usually associated with large, atmospheric explosions, such as other volcanic eruptions and nuclear tests.
