Latest news with #SchooloftheEnvironment
Miami Herald
30-05-2025
- Science
- Miami Herald
Hidden inland boulder is proof of massive tsunami that hit Tonga 7,000 years ago
On the island of Tongatapu, the main island of Tonga, researchers scoured the southern coastline for evidence of violent weather events that occurred thousands of years ago. They were specifically looking for boulders, as they can only be carried ashore or moved by massive waves in 'high-energy events, such as tsunamis or storms,' according to a May 14 study published in the journal Marine Geology. Aerial photo revealed several boulders, but the largest was hidden from view. Local farmers speaking with the researchers told them of a boulder deep inland atop a cliff, covered by dense vegetation that obscured it from aerial view, and led them to it. 'I was so surprised; it is located far inland outside of our field work area,' study author and Ph.D. candidate Martin Köhler said in a news release from The University of Queensland's School of the Environment. 'It was quite unbelievable to see this big piece of rock sitting there covered in and surrounded by vegetation,' Köhler said. Researchers said 7,000 years ago, a tsunami about 164 feet tall— the height of the Arc de Triomphe, or a giant sequoia — dislodged the enormous rock and moved it 656 feet inland. At 45 feet long, 22 feet tall, 39 feet wide and weighing 1,300 tons, the 'exceptional' Maka Lahi is the world's largest cliff-top boulder, according to the study. Models suggest the tsunami was triggered by a landslide caused by an earthquake near the Tonga-Kermadec Trench, according to the study. 'Understanding past extreme events is critical for hazard preparation and risk assessment now and in the future,' coastal geomorphologist Annie Lau said in the release. According to Lau, the region has a 'long history of tsunamis triggered by volcanic eruptions and earthquakes along the underwater Tofua Ridge and the Tonga Trench.' The research team included Martin Köhler, Annie Lau, Koki Nakata, Kazuhisa Goto, James Goff, Daniel Köhler, Mafoa Penisoni.
Scoop
26-05-2025
- Science
- Scoop
Research Shows Tonga's Maka Lahi Boulder's Journey
Article – RNZ The researchers used numerical modelling to establish that wave heights of around 50 metres, and lasting around 90 seconds, would have been needed to dislodge the boulder from its cliff-edge origin. New research theorises that Tonga's Maka Lahi boulder was moved more than 200 metres inland by a tsunami around 7,000 years ago. Maka Lahi, meaning 'Big Rock', is a limestone boulder measuring 6.7 metres tall and 14 metres wide, and weighing approximately 1180 tonnes. It is the second-largest boulder in Tonga, after Maui Rock, and sits at an elevation of 39 metres. The University of Queensland's School of the Environment PhD candidate Martin Köhler is one of the authors of the study published in Marine Geology. He said that he and his team were directed to the boulder local farmers. 'We had been surveying the southern side of the island of Tongatapu, looking along the coastal cliffs at evidence of past tsunamis,' Köhler said. '[The boulder] is located far inland, outside of our field work area, and must have been carried by a very big tsunami. 'We made a 3D model and then went back to the coast and found the spot the boulder could have come from, on a cliff over 30 metres above the sea level.' The researchers used numerical modelling to establish that wave heights of around 50 metres, and lasting around 90 seconds, would have been needed to dislodge it from its cliff-edge origin and move it to its resting place. This suggests its emplacement 'likely resulted from a landslide-triggered tsunami event', researchers said. Several wave-transported boulders (weighing 0.6-1555 t) had previously been reported on Tongatapu. 'The exceptional characteristics of the Maka Lahi boulder, including its dimensions, estimated mass of approximately 1180tn and its high elevation, rank it among the three largest coastal boulders globally and the largest cliff-top boulder in the world.' Co-author Dr Annie Lau said Tonga had a long history of tsunamis triggered by volcanic eruptions and earthquakes along the underwater Tofua Ridge and the Tonga Trench. 'The findings we have reported on the Maka Lahi boulder are the evidence of a tsunami in the Pacific region in the Holocene epoch, which began around 11,700 years ago,' she said. 'Understanding past extreme events is critical for hazard preparation and risk assessment now and in the future.' The study said like other coastal boulders on Tongatapu such as Maui Rock on the west coast and the Haveluliku boulders on the east coast, Maka Lahi is also interpreted within a mythological framework as one of the ' Maui throwing stones' believed to be deposited by the demi-god Maui, while chasing chicken(s) from 'Eua to Tongatapu, as described in a Tongan legend.
Scoop
26-05-2025
- Science
- Scoop
Research Shows Tonga's Maka Lahi Boulder's Journey
Article – RNZ The researchers used numerical modelling to establish that wave heights of around 50 metres, and lasting around 90 seconds, would have been needed to dislodge the boulder from its cliff-edge origin. New research theorises that Tonga's Maka Lahi boulder was moved more than 200 metres inland by a tsunami around 7,000 years ago. , meaning 'Big Rock', is a limestone boulder measuring 6.7 metres tall and 14 metres wide, and weighing approximately 1180 tonnes. It is the second-largest boulder in Tonga, after Maui Rock, and sits at an elevation of 39 metres. The University of Queensland's School of the Environment PhD candidate Martin Köhler is one of the authors of the study published in Marine Geology. He said that he and his team were directed to the boulder local farmers. 'We had been surveying the southern side of the island of Tongatapu, looking along the coastal cliffs at evidence of past tsunamis,' Köhler said. '[The boulder] is located far inland, outside of our field work area, and must have been carried by a very big tsunami. 'We made a 3D model and then went back to the coast and found the spot the boulder could have come from, on a cliff over 30 metres above the sea level.' The researchers used numerical modelling to establish that wave heights of around 50 metres, and lasting around 90 seconds, would have been needed to dislodge it from its cliff-edge origin and move it to its resting place. This suggests its emplacement 'likely resulted from a landslide-triggered tsunami event', researchers said. Several wave-transported boulders (weighing 0.6-1555 t) had previously been reported on Tongatapu. 'The exceptional characteristics of the Maka Lahi boulder, including its dimensions, estimated mass of approximately 1180tn and its high elevation, rank it among the three largest coastal boulders globally and the largest cliff-top boulder in the world.' Co-author Dr Annie Lau said Tonga had a long history of tsunamis triggered by volcanic eruptions and earthquakes along the underwater Tofua Ridge and the Tonga Trench. 'The findings we have reported on the Maka Lahi boulder are the evidence of a tsunami in the Pacific region in the Holocene epoch, which began around 11,700 years ago,' she said. 'Understanding past extreme events is critical for hazard preparation and risk assessment now and in the future.' The study said like other coastal boulders on Tongatapu such as Maui Rock on the west coast and the Haveluliku boulders on the east coast, Maka Lahi is also interpreted within a mythological framework as one of the ' Maui throwing stones' believed to be deposited by the demi-god Maui, while chasing chicken(s) from 'Eua to Tongatapu, as described in a Tongan legend.
Scoop
26-05-2025
- Science
- Scoop
Research Shows Tonga's Maka Lahi Boulder's Journey
New research theorises that Tonga's Maka Lahi boulder was moved more than 200 metres inland by a tsunami around 7,000 years ago. Maka Lahi, meaning "Big Rock", is a limestone boulder measuring 6.7 metres tall and 14 metres wide, and weighing approximately 1180 tonnes. It is the second-largest boulder in Tonga, after Maui Rock, and sits at an elevation of 39 metres. The University of Queensland's School of the Environment PhD candidate Martin Köhler is one of the authors of the study published in Marine Geology. He said that he and his team were directed to the boulder local farmers. "We had been surveying the southern side of the island of Tongatapu, looking along the coastal cliffs at evidence of past tsunamis," Köhler said. "[The boulder] is located far inland, outside of our field work area, and must have been carried by a very big tsunami. "We made a 3D model and then went back to the coast and found the spot the boulder could have come from, on a cliff over 30 metres above the sea level." The researchers used numerical modelling to establish that wave heights of around 50 metres, and lasting around 90 seconds, would have been needed to dislodge it from its cliff-edge origin and move it to its resting place. This suggests its emplacement "likely resulted from a landslide-triggered tsunami event", researchers said. Several wave-transported boulders (weighing 0.6-1555 t) had previously been reported on Tongatapu. "The exceptional characteristics of the Maka Lahi boulder, including its dimensions, estimated mass of approximately 1180tn and its high elevation, rank it among the three largest coastal boulders globally and the largest cliff-top boulder in the world." Co-author Dr Annie Lau said Tonga had a long history of tsunamis triggered by volcanic eruptions and earthquakes along the underwater Tofua Ridge and the Tonga Trench. "The findings we have reported on the Maka Lahi boulder are the evidence of a tsunami in the Pacific region in the Holocene epoch, which began around 11,700 years ago," she said. "Understanding past extreme events is critical for hazard preparation and risk assessment now and in the future." The study said like other coastal boulders on Tongatapu such as Maui Rock on the west coast and the Haveluliku boulders on the east coast, Maka Lahi is also interpreted within a mythological framework as one of the " Maui throwing stones" believed to be deposited by the demi-god Maui, while chasing chicken(s) from 'Eua to Tongatapu, as described in a Tongan legend.
Scoop
22-05-2025
- Science
- Scoop
Boulder Washed Inland A Sign Of Pacific Tsunami History
Analysis has shown a boulder weighing almost 1,200 tonnes in Tonga is one of the largest known wave-transported rocks in the world, providing new insights into the Pacific region's history and risk of tsunamis. PhD candidate Martin Köhler from The University of Queensland's School of the Environment says the Maka Lahi boulder measuring 14 x 12 x 6.7 metres was moved more than 200 metres inland by a tsunami around 7,000 years ago. 'We had been surveying the southern side of the island of Tongatapu looking along the coastal cliffs at evidence of past tsunamis,' Mr Köhler said. 'It was late in the day, and we were talking to some farmers when they directed us to this boulder. 'I was so surprised; it is located far inland, outside of our field work area and must have been carried by a very big tsunami. 'It was quite unbelievable to see this big piece of rock sitting there covered in and surrounded by vegetation. 'We made a 3D model and then went back to the coast and found the spot the boulder could have come from, on a cliff over 30 metres above the sea level.' The Maka Lahi boulder is the world's largest known cliff-top boulder. Numerical modelling has established that wave heights of around 50 metres lasting around 90 seconds were needed to dislodge it from its cliff-edge origin and move it to its resting place. Co-author Dr Annie Lau, a coastal geomorphologist, said Tonga had a long history of tsunamis triggered by volcanic eruptions and earthquakes along the underwater Tofua Ridge and the Tonga Trench. 'Tonga's most recent tsunami in 2022 killed 6 people and caused a lot of damage,' Dr Lau said. 'Understanding past extreme events is critical for hazard preparation and risk assessment now and in the future. 'The findings we have reported on the Maka Lahi boulder are the evidence of a tsunami in the Pacific region in the Holocene epoch which began around 11,700 years ago. 'The analysis strengthens our understanding of wave transportation of rocks to improve coastal-hazard assessments in tsunami-prone regions around the world.' The research is published in Marine Geology.
