Unbelievable Discovery: Scientists Uncover 2.6 Million-Pound Boulder Swept Ashore by Massive Tsunami!

In the lush greenery of southern Tongatapu, a massive limestone boulder lies quietly. Local farmers often overlook it, but geologists have recognized it as the heaviest cliff-top boulder ever discovered. Known as Maka Lahi, which means "Big Rock" in Tongan, this boulder offers a glimpse into Tonga’s past and the immense power of nature.

Around 7,000 years ago, a colossal tsunami struck Tonga. This boulder serves as evidence of that violent event. Martin Köhler, a researcher from the University of Queensland, made this remarkable finding while surveying coastal cliffs for signs of past tsunamis. Farmers directed him to the rock, located more than 200 meters inland. It was a surprising discovery.

Köhler’s team used drones and laser scans to create a detailed 3D model of the boulder, measuring approximately 14 meters long and weighing about 1,180 tons — heavier than three Boeing 747 jets. The limestone’s chemical makeup matched that of nearby corals, indicating it originally came from a cliff over 30 meters above sea level.

But how did it get there? Research indicates that only a tsunami generated by a landslide could have displaced such a substantial boulder. This wave would need to be at least 50 meters high and last around 90 seconds to transport the rock inland at speeds exceeding 20 meters per second. This terrifying force deposited Maka Lahi at a height of 39 meters above today’s sea level.

Uranium-thorium dating places the tsunami event at roughly 6,900 years ago. Annie Lau, another researcher involved in the study, emphasizes that understanding past tsunamis is vital for future risk assessments. The recent 2022 tsunami tragically claimed lives and caused significant damage in Tonga.

The research on Maka Lahi could improve coastal hazard assessments worldwide. Similar massive boulders exist along coastlines from the Mediterranean to the Caribbean, and understanding their history helps predict future risks. Experts warn that as climate change intensifies, coastal erosion could increase the frequency of huge tsunami waves.

Local legends contribute to this narrative, recalling demigod Māui casting rocks into the sea while pursuing birds. These stories might reflect real historical events, offering a cultural counterpart to scientific research.

Looking ahead, Tonga’s population predominantly resides in coastal areas, where current evacuation plans assume wave heights around 20 meters. However, a wave as large as 50 meters could surpass these zones, potentially flooding major cities like Nuku‘alofa. Updating hazard models to include such extreme scenarios is crucial for public safety.

As we learn from Maka Lahi, the past teaches us valuable lessons about nature’s might. It’s clear that even tranquil coastlines have experienced cataclysmic waves strong enough to reshape the land. Understanding this history is essential for preparing against future disasters.

This research was published in Marine Geology, contributing significantly to our knowledge of tsunami dynamics and coastal risks.

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