How Did This 1,300-Ton Boulder Travel Up a Cliff? Scientists Just Figured It Out

A giant boulder in Tonga rode a wave from an ancient tsunami 7,000 years ago. The 1,300-ton rock traveled a distance twice the size of a football field, swept away by the sheer force of the wave, according to a new study. But this was no ordinary giant rock. It was also sitting on a 100-foot (30-meter) tall cliff before surfing to its new location—hinting at a past mega-tsunami that swept the region. In July of 2024, Martin Kohler, a PhD candidate from the University of Queensland, and his team were doing fieldwork on Tonga’s cliffs, searching for evidence of past tsunamis. In particular, they were looking for large boulders that could have been carried inland, which can tell researchers a lot about the history of tsunamis in earthquake-prone regions, like Tonga. On one of their last field days, some local farmers told the researchers about a boulder they might be interested in. The rock, familiar to locals as Maka Lahi, or literally “large rock,” had never been studied by scientist ... Read full article.