Tonga Boulder Reveals Ancient Tsunami's Power

Researchers have identified the Maka Lahi boulder on Tongatapu, Tonga, as the world's largest known cliff-top boulder moved by a tsunami, weighing nearly 1,200 tonnes and measuring 14 by 12 by 6.7 meters. The boulder was transported over 200 meters inland and atop a 30-meter cliff by a massive tsunami approximately 7,000 years ago. Numerical modeling and 3D simulations suggest a wave at least 50 meters high and lasting about 90 seconds was required to move it. The discovery, made after local farmers alerted researchers to the site, provides new insights into the region's tsunami history. It also emphasizes the importance of understanding extreme past events to improve future coastal hazard preparedness. The findings enhance scientific knowledge of wave-transported boulders and tsunami risk in the Pacific.