Latest news with #ThomasMonahan
BBC News
3 days ago
- Science
- BBC News
Oxford study finds 'extraordinary' tremors caused by tsunamis
A series of "extraordinary" tremors observed across the globe were caused by two tsunamis stranded within a fjord in Greenland, a new study has September and October 2023, the "bizarre" seismic activity was observed every 90 seconds over intermittent periods each University of Oxford-led research confirmed it was caused by two mega tsunamis, which occurred after the warming of a glacier led to two major tsunamis became trapped standing waves that surged back and forth within the remote Dickson fjord in eastern Greenland, causing the tremors, the study found. The research's lead author Thomas Monahan, from the University of Oxford, said: "Climate change is giving rise to new, unseen extremes."These extremes are changing the fastest in remote areas, such as the Arctic, where our ability to measure them using physical sensors is limited." To conduct the study into what researchers called the "extraordinary" tremors , scientists used new techniques to interpret data recorded by satellites orbiting the altimetry data measures the height of the Earth's surface by recording how long it takes for a radar pulse to travel from a satellite to the surface and back altimeters were unable to record evidence of the Greenland tsunamis, but a satellite launched in December 2022 had the equipment capable of doing so - allowing researchers to observe the trapped waves."This study shows how we can leverage the next generation of satellite earth observation technologies to study these processes," Mr Monahan of the study Prof Thomas Adcock added: "This study is an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past."We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves." You can follow BBC Oxfordshire on Facebook, X (Twitter), or Instagram.
Economic Times
3 days ago
- Science
- Economic Times
Dickson Fjord's 650-foot mega-tsunami: How a giant wave sent shockwaves worldwide
Mega-tsunamis rock Greenland's Fjord Seiches vs. Tsunamis: The science behind the waves Live Events How advanced satellites and machine learning solved the puzzle Climate Change: The silent driver A breakthrough in Earth monitoring (You can now subscribe to our (You can now subscribe to our Economic Times WhatsApp channel In September 2023, seismic stations worldwide began picking up an unusual, rhythmic signal repeating every 90 seconds. This steady pulse continued for nine days and returned briefly a month later. It was faint, unlike a typical earthquake, but strong enough to register across continents—from Alaska to Australia. Scientists were baffled. No known earthquake, volcanic eruption, or explosion had caused source was traced to the remote Dickson Fjord in East Greenland, a narrow inlet bordered by towering cliffs. But what exactly had triggered this steady, global beat?The answer lay in a massive natural disaster: on 16 September 2023, more than 25 million cubic metres of rock and ice—a volume large enough to fill 10,000 Olympic swimming pools—collapsed from the mountainside into Dickson Fjord. This triggered a mega-tsunami with waves reaching 650 feet high, about half the height of the Empire State waves surged along the two-mile-long fjord, smashing against cliffs and bouncing back, creating a prolonged sloshing motion known as a seiche. Unlike tsunamis, which travel outward as single giant waves, seiches occur when water oscillates repeatedly in an enclosed space. This ongoing motion produced rhythmic seismic pulses detectable around the are caused by sudden, large displacements of water—usually due to earthquakes, landslides, or volcanic eruptions—and travel as single massive waves. Seiches, however, are standing waves formed in enclosed or semi-enclosed bodies of water, like lakes or fjords. They can be triggered by landslides or strong winds, causing the water to rock back and forth in a steady Dickson Fjord, the narrow, enclosed shape trapped the tsunami energy. The waves couldn't escape, so they kept bouncing, sending low-frequency seismic energy through the Earth's crust for mystery was unraveled thanks to the Surface Water and Ocean Topography (SWOT) satellite, a joint NASA and French space agency mission launched in December 2022. Unlike traditional satellites that scan narrow lines, SWOT uses Ka-band Radar Interferometer (KaRIn) technology to map wide swaths of ocean surface in high SWOT data, researchers observed subtle water elevation changes—slopes of up to two metres—sloshing across the fjord. These shifts matched the oscillations expected from fill gaps, scientists employed machine learning to simulate wave behaviour over time. They also analysed crustal deformation data from sensors thousands of kilometres away, plus weather and tidal records, ruling out other causes like researcher Thomas Monahan, a University of Oxford engineering student, said, 'Climate change is giving rise to new, unseen extremes. These changes are happening fastest in remote areas like the Arctic, where our ability to monitor them has historically been limited.'The underlying cause of the landslide was the rapid melting of Greenland's glaciers. As glacier ice shrinks, it removes the natural support holding mountainsides in place. This weakening triggers massive rock and ice explained, 'Climate change is shifting what is typical on Earth, and it can set unusual events into motion.' Past disasters, like a deadly tsunami in Karrat Fjord in 2017, show how these events can devastate local Fjord lies near popular cruise routes, raising concerns about future risks as Arctic tourism grows. Authorities are now exploring early-warning systems combining satellite data and real-time seismic monitoring to protect people in vulnerable event represents a turning point in how we observe and understand Earth's dynamic processes. Professor Thomas Adcock of Oxford said, 'This study is an example of how the next generation of satellite data can resolve phenomena that have remained a mystery in the past.'He added, 'We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves. To fully harness these data, we need to innovate using both machine learning and ocean physics.'A Danish military vessel patrolled the fjord three days after the first pulse but observed nothing unusual. This shows how even massive natural events can leave little trace without sophisticated monitoring are now searching through historical seismic data for similar slow, rhythmic pulses. Carl Ebeling from UC San Diego said, 'This shows there is stuff out there that we still don't understand and haven't seen before.'Every new discovery will improve forecasts of how landslides, fjord shapes, and water depth interact. The hope is to provide early warnings that could save lives in remote, high-latitude silent, powerful waves in Greenland's fjord prove one thing: the most isolated places on Earth are changing fast—and we must listen carefully to what they tell us.
Daily Tribune
5 days ago
- Science
- Daily Tribune
Scientists Crack Mystery Behind Planet-Shaking Nine-Day Tremors
A year after the Earth mysteriously trembled every 90 seconds for nine days straight—twice—scientists have finally traced the cause of the bizarre global seismic activity. The long-standing mystery has now been put to rest, thanks to a breakthrough study using cutting-edge satellite technology. In September 2023, seismometers around the world picked up rhythmic tremors occurring at regular 90-second intervals. The unexplained shaking lasted for nine days and reoccurred just a month later. These anomalies defied all known tectonic behavior and left scientists around the globe searching for answers. Now, in a study published in Nature Communications, researchers led by Thomas Monahan, a Schmidt AI in Science Fellow at the University of Oxford, have confirmed that the unusual seismic signals were caused by two colossal landslides in East Greenland's remote Dickson Fjord. These massive collapses triggered equally massive "mega-tsunamis," which in turn produced a phenomenon known as seiches—enormous standing waves that repeatedly sloshed within the fjord, creating rhythmic pulses that shook the Earth's crust. 'Previous studies in 2024 proposed the landslide-tsunami theory based on seismic patterns, but we lacked direct evidence to conclusively prove the link,' said Monahan. 'Our research now confirms it.' The key breakthrough came from data collected by NASA's Surface Water and Ocean Topography (SWOT) satellite, launched in December 2022. Using a unique radar altimetry technique, SWOT is capable of mapping water levels across 90% of Earth's surface in stunning detail. While traditional satellites missed the phenomenon due to infrequent measurements and complex fjord topography, SWOT's high-resolution twin-antenna system succeeded where others failed. The satellite captured the dynamic surface changes in the fjord as the seiches surged back and forth, providing the first-ever direct observations of the event and allowing researchers to match them precisely with the seismic data. 'This is a prime example of how new technology can transform our understanding of natural phenomena,' Monahan noted. The findings not only close a major scientific mystery but also open new pathways for monitoring remote and rugged environments using advanced satellite systems. As Earth's climate continues to shift, such insights could prove vital in understanding and anticipating the impacts of sudden geological events.
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."
Gizmodo
7 days ago
- Science
- Gizmodo
Mega-Tsunamis That Shook the World for 9 Days Revealed in New Satellite Images
Scientists have finally solved the mystery behind two strange events that shook the entire planet for nine days straight. Their findings close the book on a years-long effort to trace the seismic signals back to their source. In September 2023, global seismometers detected something strange. The Earth was experiencing minor tremors every 90 seconds—and the shaking went on for nine days. One month later, it happened again. Scientists were baffled, as natural tectonic processes couldn't explain the anomalies. After roughly a year of scientific sleuthing, two studies published in 2024 independently hypothesized that the shaking resulted from two huge landslides, setting off two 'mega-tsunamis' in the Dickson Fjord in East Greenland. These enormous standing waves—or seiches—sloshed back and forth inside the fjord and triggered small movements within the Earth's crust, they posited. It was an intriguing possibility, and both studies presented compelling evidence to support their claims. But, 'there were some big uncertainties that made it difficult to fully corroborate that this was actually the root cause,' Thomas Monahan, a Schmidt AI in Science fellow at the University of Oxford, told Gizmodo. So, Monahan and his colleagues set out to confirm whether this hypothesis was correct. In a study published today in the journal Nature Communications, they unveiled the first direct satellite observations of the seiches and definitively linked them to the seismic anomalies. The researchers used data captured by NASA's Surface Water Ocean Topography (SWOT) satellite, which launched in December 2022 to map the height of water across 90% of Earth's surface. This type of data collection—known as satellite altimetry—works by transmitting radar pulses from a satellite to Earth's surface, and then measuring the time it takes for the signals to bounce off the surface and return to the satellite. Conventional altimeters failed to capture evidence of the seiches due to long gaps between observations, according to an Oxford statement. As such, they generally struggle to gather data in fjord regions due to the complexity of the terrain, Monahan said. But SWOT is equipped with a cutting-edge altimeter instrument that uses two antennas to triangulate the return signals. This allows the satellite to take very high-resolution measurements of surface water levels. 'What we're able to get is essentially an incredibly high-resolution snapshot of what the elevation of the sea surface is doing in these complex regions,' Monahan said. These snapshots provided a more accurate picture of how the fjord's sea surface height changed during the 2023 seismic events, allowing his research team to calculate the slopes of the massive waves that had formed. 'We were able to essentially unearth the fact that there was a significant anomaly in the fjord exactly when we would expect this wave to occur,' Monahan said. But determining that these seiches formed at the same time as the strange seismic signals still wasn't enough to prove the two events were linked. The researchers needed direct evidence to prove that these huge waves were capable of generating global tremors. To that end, they linked the SWOT snapshots to small movements in the Earth's crust detected at seismic stations located thousands of miles away from the fjord. Coupling this continuous seismic data with the intermittent satellite observations allowed them to reconstruct the characteristics of the wave, even for periods that SWOT did not observe. The researchers also ruled out the possibility that the seismicity stemmed from weather or tidal conditions and ultimately determined that the seiches were the sources of the tremors. These waves formed when a warming glacier collapsed in on itself, Monahan said. 'This created very large landslides, which—when they struck the fjord—produced massive mega-tsunamis on the order of 200 meters or 600 feet tall,' he explained. 'This was the first time that a mega-tsunami of that nature had occurred in Eastern Greenland,' Monahan said, adding that this type of event has been documented on the territory's west coast. To see this phenomenon spreading to other parts of the ice sheet 'is concerning,' he said, because it shows that climate change is accelerating in this region. 'I think what this study really emphasizes is that—well, it sounds silly to say—but climate change is a global phenomenon,' Monahan said. 'Some of the biggest and fastest changes are occurring in the Arctic and in remote regions where we may not see it every single day. But it's important to understand and quantify those changes as they will eventually come to impact us where we live,' he said. Indeed, the waves that shook the world offer a stark reminder of the sweeping impacts of rising global temperatures.
