Overview

• The Maka Lahi boulder, weighing 1,200 tonnes and measuring 14 by 12 by 6.7 meters, is the largest known cliff-top boulder globally.
• Located over 200 meters inland and nearly 30 meters above sea level, it was transported by a tsunami approximately 7,000 years ago during the early Holocene.
• Numerical simulations suggest a 50-meter-high wave sustained for 90 seconds was required to dislodge and move the boulder.
• The discovery, published in the May 2025 issue of Marine Geology, integrates fieldwork, local insights, and advanced 3D modeling to refine tsunami hazard assessments.
• Findings challenge traditional tsunami wave models and underscore the importance of prehistoric tsunami studies for modern coastal risk mitigation.