Latest news with #mega-tsunami
Yahoo
6 days ago
- Science
- Yahoo
Mysterious 'mega-tsunamis' that shook the entire world for 9 days revealed by satellite
When you buy through links on our articles, Future and its syndication partners may earn a commission. Scientists have made the first direct observations of a strange seismic event that shook the world for nine consecutive days in 2023 and confirmed its cause: two "mega-tsunamis" that sloshed around an East Greenland fjord. The gigantic waves — one of which measured 650 feet (200 meters) high, or about half the height of the Empire State Building — entered East Greenland's Dickson Fjord and rocked back and forth for nine days in September 2023, sending seismic waves reverberating through the planet's crust. The signal was initially a mystery to scientists, but ground and satellite imagery traced the likely culprit to landslides in the fjord. These landslides unleashed the waves, known as seiches, following the climate-change-induced melting of a glacier behind the fjord. However, no direct evidence of these seiches was found. Now, the theory has been confirmed by a new satellite that tracks water on the surface of the ocean. The findings were published Tuesday (June 3) in the journal Nature Communications. "Climate change is giving rise to new, unseen extremes," study lead author Thomas Monahan, a graduate student in engineering science at the University of Oxford, said in a statement. "These extremes are changing the fastest in remote areas, such as the Arctic, where our ability to measure them using physical sensors is limited. This study shows how we can leverage the next generation of satellite Earth observation technologies to study these processes." Related: 'This is a very big earthquake': The science behind Myanmar's magnitude 7.7 earthquake Typically, scientists study the movements of tsunami waves using a method called satellite altimetry, in which radar pulses are sent to the ocean's surface from orbit to measure a wave's height based on the time it takes for the pulses to return. But because satellites have long gaps in coverage and their instruments can only measure what's beneath them, they are unable to measure the differences in water height in confined areas like those within the fjord. To confirm the existence of the seiches, the scientists turned to data captured by the new Surface Water and Ocean Topography (SWOT) satellite, a joint project of NASA and CNES, France's space agency. Launched in December 2022, the satellite uses an instrument called the Ka-band Radar Interferometer (KaRIn) to map 90% of the water across the ocean's surface. KaRIn works by using two antennae mounted across a boom on each side of the satellite to triangulate the return signals of radar pulses with unprecedented accuracy — measuring water levels with a resolution of up to 8.2 feet (2.5 m) along a 30-mile (50 kilometers) arc. RELATED STORIES —Alarming collapse of Greenland ice shelves sparks warning of sea level rise —Greenland lost enough ice in the last 2 decades to cover the United States in 1.5 feet of water —What's the difference between a tsunami and a tidal wave? SWOT data taken above the fjord during the two mega-tsunamis revealed two cross-channel slopes moving in opposite directions between it, confirming their presence. Seismic observations made thousands of miles away, alongside weather and tidal readings, further enabled the researchers to reconstruct the waves and conclusively link them to the mysterious seismic signals. "This study is an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past," co-author Thomas Adcock, a professor of engineering science at the University of Oxford, said in the statement. "We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves," he added. "However, to get the most out of these data we will need to innovate and use both machine learning and our knowledge of ocean physics to interpret our new results."
The Independent
21-05-2025
- Science
- The Independent
How a strong earthquake could put parts of US in the sea
Scientists are warning that a potential "mega- tsunami" up to 1,000 feet tall could devastate parts of the American West Coast, Alaska, and Hawaii. This could be triggered by a major earthquake along the Cascadia subduction zone, a fault line stretching from Vancouver Island to California. There is a 15 per cent chance of a magnitude 8.0 or greater earthquake hitting the region within the next 50 years, according to a study. Such an earthquake could also cause coastal land to sink by up to 6.5 feet, exacerbating the tsunami's impact. Cities like Seattle and Portland are particularly vulnerable, and the event would occur rapidly, leaving little time for response, experts say.
Daily Mail
19-05-2025
- Climate
- Daily Mail
Scientists warn of possible 1,000ft tsunami risking US coastal areas
Alaska Hawaii Hawaii's volcanic islands have a history of mega-tsunamis driven by collapsing volcanoes. Around 105,000 years ago, a 1,000-foot wave slammed into the island of Lanai, leaving marine fossils high on its mountains. Researchers believe this was caused by a massive volcanic landslide, similar to the Cumbre Vieja scenario. Other ancient slides, like the 20-mile-long Nu'uanu slide, sent huge volumes of rock into the sea, generating waves up to 300 feet high that reshaped the islands' coasts. Hawaii's volcanoes grow by piling up layers of lava, but these slopes can become unstable and collapse, especially during eruptions or earthquakes. This can cause millions of tons of rock to slide into the ocean, creating mega-tsunamis that devastate nearby islands. The islands' steep terrain makes these events particularly dangerous. The West Coast On January 26, 1700, a magnitude 9 earthquake along the Cascadia Subduction Zone unleashed a mega-tsunami that destroyed the village of Pachena Bay on the West Coast. Waves up to 100 feet high struck just 30 minutes after the quake, leaving no survivors. Huu-ay-aht Chief Louis Clamhouse, speaking in 1964, shared the oral history: 'The land shook at night… they had no time to escape. All drowned.' The quake also lowered coastal forests into the tidal zone, creating 'ghost forests' of dead tree stumps still visible today. Across the Pacific, Japan recorded a mysterious tsunami, later linked to this event. A similar event could trigger a tsunami like Japan's 2011 Tohoku-oki disaster, which killed nearly 16,000 people. The US Geological Survey and FEMA have estimated that there's a 37 percent chance of a magnitude 8 to 9 earthquake in Cascadia within the next 50 years. Coastal towns like Tillamook, Astoria, and Newport could be submerged, with parts of the coast sinking permanently. Researchers are improving early warning systems and evacuation plans, but the region's vulnerability to earthquakes keeps the tsunami threat alive. Alaska, Hawaii, and the West Coast face ongoing risks of mega-tsunamis due to their active geology and changing environments. Landslides fueled by melting glaciers in Alaska, unstable volcanoes in Hawaii, and powerful earthquakes along the West Coast could unleash catastrophic waves, as they have in the past. While scientists monitor these dangers and communities prepare through planning and education, the threat remains real. Want more stories like this from the Daily Mail? Hit the follow button above for more of the news you need.
Daily Mail
19-05-2025
- Science
- Daily Mail
Experts issue urgent warning over 1,000ft tall 'mega tsunami' set to hit parts of the US... is your hometown at risk?
Imagine a wall of water up to a third of a mile high, roaring across the ocean at hundreds of miles per hour. The sheer destructive force of a mega-tsunami is almost beyond comprehension. Unlike regular tsunamis caused by earthquakes, mega-tsunamis are often triggered by huge landslides or collapsing volcanoes. Three regions in the US — Alaska, Hawaii, and the West Coast — face the threat of mega-tsunamis due to their proximity to unstable volcanoes, landslide-prone areas, and earthquake zones. One dramatic example occurred millions of years ago when an asteroid impact triggered a mile-high mega-tsunami during the time of the dinosaurs, leaving traces scientists still study. Today, one chilling possibility involves the Cumbre Vieja volcano on the Canary Island of La Palma, which could collapse into the Atlantic and send a mega-tsunami toward the US East Coast. The Netflix series 'La Palma' brings this scenario to life, showing a family on vacation as researchers discover signs of a volcanic eruption that could unleash a catastrophic wave. This idea comes from a 2001 study by Dr Simon Day and Steven Ward, who warned that a collapse of Cumbre Vieja's west flank could drop up to 120 cubic miles of rock into the sea, creating a massive wave. Their research suggests this wave could start at 2,000 feet high near the volcano and still reach up to 150 feet when it hits the Americas, threatening coastal cities. While some experts argue this Cumbre Vieja scenario is unlikely, as the volcano has erupted without causing such a tsunami, the US faces far more immediate mega-tsunami risks in three regions: Alaska, Hawaii, and along the West Coast. These areas have experienced devastating waves in the past, triggered by landslides, volcanic collapses, or earthquakes - processes similar to those studied in the Canary Islands. Today, ongoing geological activity and environmental changes make these regions vulnerable to future mega-tsunamis, threatening coastal communities and millions of people. Alaska In 1958, an earthquake in Alaska's Lituya Bay triggered a massive landslide, sending millions of tons of rock crashing into Gilbert Inlet. The huge mass of rock was approximately 2,400 feet by 3,000 feet and is believed to weigh up to 90 million tons. It was equivalent to dropping eight million dump truck loads into the water, according to NASA. The result was the tallest wave ever recorded, a 1,719-foot mega-tsunami that roared across the bay. Eyewitnesses reported a loud 'boom' as ice-filled waves swept away lighthouses and stripped forests bare, leaving a 'razor-cut' line noted by explorers as early as 1786. One fisherman's boat was lifted so high he looked down on treetops, while another couple was never seen again. Like the Cumbre Vieja scenario, Lituya Bay's mega-tsunami was driven by a landslide. Earthquakes in this region can shake loose massive amounts of rock from steep cliffs, displacing water and creating enormous waves. The confined waters of the bay amplified the wave's height, making it especially destructive. Alaska's rugged terrain and frequent earthquakes continue to make it a hotspot for landslides. Climate change is worsening the threat by melting glaciers, which destabilizes slopes and loosens rocks. In 2020, 14 scientists warned that the retreat of Barry Glacier could trigger a rockslide into Harriman Fiord, potentially causing a massive tsunami as large as Lituya Bay's. Steve Masterman, director of Alaska's Division of Geological Surveys, emphasized that these events are becoming increasingly likely as temperatures warm. Scientists are now monitoring glaciers and slopes to predict and prepare for future disasters. Hawaii Hawaii's volcanic islands have a history of mega-tsunamis driven by collapsing volcanoes. Around 105,000 years ago, a 1,000-foot wave slammed into the island of Lanai, leaving marine fossils high on its mountains. Researchers believe this was caused by a massive volcanic landslide, similar to the Cumbre Vieja scenario. Other ancient slides, like the 20-mile-long Nu'uanu slide, sent huge volumes of rock into the sea, generating waves up to 300 feet high that reshaped the islands' coasts. Hawaii's volcanoes grow by piling up layers of lava, but these slopes can become unstable and collapse, especially during eruptions or earthquakes. This can cause millions of tons of rock to slide into the ocean, creating mega-tsunamis that devastate nearby islands. The islands' steep terrain makes these events particularly dangerous. Hawaii's volcanoes remain active, with the Big Island's southeast side - home to 'younger' volcanoes like Kilauea and Mauna Loa - posing the greatest threat. In fact, Kilauea has been actively spewing out lava for months. The last eruption in its ongoing cycle ended on May 6. Penn State researchers warn that these unstable slopes could collapse again, triggering massive waves. The ongoing volcanic activity and frequent earthquakes keep the islands at high risk for tsunamis. Scientists are monitoring volcanic movements and landslide-prone areas, but residents and visitors must remain ready for sudden tsunami alerts and evacuation orders. The West Coast On January 26, 1700, a magnitude 9 earthquake along the Cascadia Subduction Zone unleashed a mega-tsunami that destroyed the village of Pachena Bay on the West Coast. Waves up to 100 feet high struck just 30 minutes after the quake, leaving no survivors. Huu-ay-aht Chief Louis Clamhouse, speaking in 1964, shared the oral history: 'The land shook at night… they had no time to escape. All drowned.' The quake also lowered coastal forests into the tidal zone, creating 'ghost forests' of dead tree stumps still visible today. Across the Pacific, Japan recorded a mysterious tsunami, later linked to this event. Unlike landslide-driven tsunamis, the Cascadia mega-tsunami was caused by a massive seismic event, where one tectonic plate slides beneath another. This movement displaces massive amounts of ocean water, sending tsunamis across vast distances. The 1700 event showed how far-reaching these waves can be. The Cascadia Subduction Zone remains one of the most active seismic zones in North America, with a high chance of another major earthquake in the coming decades. A similar event could trigger a tsunami like Japan's 2011 Tohoku-oki disaster, which killed nearly 16,000 people. The US Geological Survey and FEMA have estimated that there's a 37 percent chance of a magnitude 8 to 9 earthquake in Cascadia within the next 50 years. Coastal towns like Tillamook, Astoria, and Newport could be submerged, with parts of the coast sinking permanently. Researchers are improving early warning systems and evacuation plans, but the region's vulnerability to earthquakes keeps the tsunami threat alive. Alaska, Hawaii, and the West Coast face ongoing risks of mega-tsunamis due to their active geology and changing environments. Landslides fueled by melting glaciers in Alaska, unstable volcanoes in Hawaii, and powerful earthquakes along the West Coast could unleash catastrophic waves, as they have in the past.
