A giant rock in Tonga rode a wave of ancient tsunami 7,000 years ago. The 1,300-ton rock traveled distance double the size of a football field, swept by the pure strength of the wave, according to a new study.
But this was not an ordinary giant rock. It also sat on a 100-foot (30-meter) high cliff before surfing to its new location-hinting at a past mega-tsunami, which swept the region.
In July 2024, Martin Kohler, a doctoral candidate from the University of Queensland, and his team did field work on Tonga’s cliffs, seeking evidence of past tsunamis. In particular, they sought large rocks that could be carried inland, which can tell researchers a lot about the history of tsunami in earthquake regions, like Tonga.
In one of their last field days, some local farmers told the rock researchers they might be interested in. The rock, familiar to locals like Placeor literally “big rock”, has never been studied by scientists. It probably wore previous satellite searches for tsunami-swept rocks because of its thick coat of vegetation.
The rock was made of coral reef -a balcony, suggesting that it came from somewhere near the coast. “I was so surprised; it is located far inland outside our field work and has to be carried by a very large tsunami,” Kohler said in a Statement. The researchers’ findings were published in the newspaper Marine geology.
The researchers later found a huge gas in a 100-foot (30-meter) high cliff near the ocean, about 650 feet (200 meters) away from the current position of the Boulder. They also determined that the rock was deposited 6,891 years ago, before people settled on Tonga.
The researchers measured the rock at 45 per 20 feet (14 per 12 per 7 meters) high, about the size of a two -story house. It now has the honor to be the third largest tsunami-swept rock in the world. And it is the largest rock that was sailed by a tsunami of a cliff.
The team then used computer modeling to calculate about how high the ancient tsunami that carried Place must be. They concluded that the tsunami was, at least 164 feet (50 meters high and would have taken about a minute and a half to pass. The tsunami probably reached speeds of over 70 miles per hour (113 kilometers per hour). It was huge and very powerful, and the researchers think that an earthquake, instead of an earthquake, initially triggered the wave.
Tonga sees a lot of geological activity that can trigger tsunamis, like the devastating tsunami in 2022. Understanding more about the mechanics of past tsunamis can help researchers better prepare for future events, co -author Annie Lau, a coastal geomorphologist at the University of Queensland, said in a statement.
“The analysis strengthens our understanding of wave transportation of rocks to improve coastal danger in regions inclined by tsunami around the world,” Lau said.
