Latest news with #ThomasAdcock
Yahoo
5 days ago
- Science
- Yahoo
We've Finally Seen The Skyscraper Tsunami That Shook Earth For 9 Days
In September 2023, Earth rumbled. Seismic monitoring all over the globe registered a strange signal that repeated every 90 seconds over a whopping nine days, petering out in a way never before seen. Then the same thing happened a month later. Subsequent analysis of those signals determined that the cause of that trembling was likely a giant megatsunami rocking back and forth, slapping against the sides of a fjord in Greenland – generating a standing wave known as a seiche. Now, scientists have finally actually seen the event, in satellite data captured while the event was in progress. It's the observation needed to confirm that the cause of the seismic signal was indeed a seiche, giving us an answer to the age-old question: if a seiche forms in a Greenland fjord and no one is around to see it, does it shake the planet? "This study is an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past," says ocean engineer Thomas Adcock of the University of Oxford in the UK. "We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves. 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." According to the analysis of the seismic data, the trigger that unleashed the megatsunami was a melting glacier that sent two giant landslides toppling into the remote Dickson fjord in East Greenland. The resulting splashes generated powerful tsunamis that, with nowhere else to go, sloshed back and forth for days, reaching a peak height of 7.4 to 8.8 meters (24.3 to 28.9 feet). Because of the remote location, however, no one actually saw either event – not even a military vessel that visited the fjord three days into the first one. But humanity has eyes in the sky. There's a satellite mapping technique called altimetry that measures the height of the surface of the planet (including bodies of water) based on how long it takes a radar signal to travel down to the surface and bounce back up again. Most altimetry measurements were unable to record the seiches, because the resolution isn't high enough and the measurements are taken too far apart in time. But a NASA mission launched in 2022 called the Surface Water Ocean Topography (SWOT) satellite has an instrument that is able to take measurements of the height of water with unprecedented precision. The satellite just so happened to have taken measurements at intervals during the days following both events. So the researchers on the new study used this data, collected by SWOT's Ka-band Radar Interferometer, to compile elevation maps of the fjord. Their results showed clear and significant height variations in the water, which was rising as a 2-meter standing wave reverberating back and forth across the fjord. That was it: the team had finally laid eyes on the seiches that were thought to have sent such strange signals rumbling around the world. The next step was to link the two phenomena. By comparing their observations to seismic data, the researchers were able to reconstruct the characteristics of each wave, and the evolution of each event, even for time periods that the satellite had not observed. They were able to rule out other possible explanations for the seismic signals, and confirm that the seiches were responsible. It's a beautifully tidy result that will help us study such events in the future. "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," says engineer Thomas Monahan of the University of Oxford. "This study shows how we can leverage the next generation of satellite Earth observation technologies to study these processes. SWOT is a game changer for studying oceanic processes in regions such as fjords which previous satellites struggled to see into." The research has been published in Nature Communications. Astronauts Reveal The Shocking Beauty of Lightning From Space Sloths The Size of Elephants Roamed America, Before Abruptly Vanishing This Giant Snail Lays Eggs Out of Its Neck… Yes, Seriously
NDTV
7 days ago
- Climate
- NDTV
Greenland's 650-Foot Mega-Tsunami Shook Earth For 9 Days, Satellite Data Confirms
In September 2023, a colossal landslide in Greenland's Dickson Fjord unleashed a 650-foot (200-metre) high mega-tsunami, causing the Earth to vibrate every 90 seconds for nine consecutive days. This unprecedented seismic event puzzled scientists until recent satellite data provided clarity. The Surface Water and Ocean Topography (SWOT) satellite, equipped with advanced radar technology, detected the persistent oscillations-known as seiches-within the fjord. These seiches resulted from approximately 25 million cubic meters of rock and ice crashing into the fjord, a consequence of glacier melting due to climate change. The findings were published Tuesday (June 3) in the journal Nature Communications. The fjord's unique geography trapped the tsunami's energy, preventing it from dissipating quickly. This event has highlighted the profound and far-reaching impacts of global warming, triggering the need for vigilant monitoring of vulnerable regions. To prove their theory, the researchers linked these observations to small movements of the Earth's crust measured thousands of kilometres away. This connection enabled them to reconstruct the characteristics of the wave, even for periods that the satellite did not observe. The researchers also reconstructed weather and tidal conditions to confirm that the observations could not have been caused by winds or tides. Lead author Thomas Monahan (DPhil student, Department of Engineering Science, University of Oxford) said in a statement, "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. This study shows how we can leverage the next generation of satellite earth observation technologies to study these processes." "SWOT is a game changer for studying oceanic processes in regions such as fjords, which previous satellites struggled to see into." Co-author Professor Thomas Adcock (Department of Engineering Science, University 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. We will be able to get new insights into ocean extremes such as tsunamis, storm surges, and freak waves. 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."
New York Post
7 days ago
- Climate
- New York Post
‘Mega-tsunami' mystery solved — source of seismic activity that shook the world for 9 days revealed
This ought to cause a wave of panic. Back in 2023, scientists were perplexed by a mysterious seismic signal that shook the world every 90 seconds for nine days. Now, two years later, satellite footage has revealed the frightening source of these vibrations — giant mega-tsunamis sloshing around a Greenland fjord, per a 'Nature Communications' study. The massive walls of water — one of which measured 650 feet tall, or about half the height of the Empire State Building — were reportedly caused by the collapse of a massive mountainside that was triggered by a warming glacier, per the report. A total of 25 million cubic meters of rock and ice crashed into remote Dickson Fjord in East Greenland, the Daily Mail reported. This spawned colossal waves known as seiches that undulated back and forth in the water body for nine days like a giant bathtub or wave pool — hence the mysterious reverberations, Live Science reported. Study co-author Professor Thomas Adcock, who teaches engineering science at the University of Oxford, dubbed the findings 'an example of how the next generation of satellite data can resolve phenomena that has remained a mystery in the past.' í¥¤§í¨²´ çŸ³í¤°â¢ – 'That is an enormous wall of water bouncing back and forth,' study lead author Thomas Monahan, a graduate student in engineering science at the University of Oxford, told the Daily Mail. He estimated that the force exerted over the length of the fjord was 500 Giga Newtons, the 'equivalent to the amount of force produced by 14 Saturn V rocket ships launching at once.' While this seismic phenomenon was felt around the world, there were no observations of these tsunamis or landslides to confirm the theory. Even a Danish military vessel that entered the fjord three days into the first seismic event didn't observe the seiche rocking the planet. Thankfully, the Oxford researchers were able to fill in the blanks by analyzing data captured by the new Surface Water and Ocean Topography (SWOT) satellite, which, as the name suggests, tracks water on the surface of the ocean. Using a tool called Ka-band Radar Interferometer (KaRIn), the tech can map 90% of all water on the ocean's surface. Copernicus Sentinel-2 satellite image of the Dickson Fjord overlaid with sea-surface height measurements from the SWOT satellite. Thomas Monahan The traditional tsunami-measuring method, satellite altimetry, involves transmitting radar pulses onto the ocean's surface from orbit and then measuring the wave's height based on the time it takes for the pulse to return. Unfortunately, this technique is somewhat limited as it can't conduct accurate measurements in a confined space such as the fjord. By contrast, KaRin can pinpoint radar signals' returns with shocking precision using two massive antennae. Armed with this tech, Fjord forensics experts were able to observe cross-channel slopes moving in opposite directions between the fjord, confirming their presence. They then cross-referenced this with seismic observations, as well as weather and tidal readings, to recreate the waves and connect them to the reverberations. Study co-author Professor Thomas Adcock, who teaches engineering science at the University of Oxford, dubbed the findings '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,' he said. '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.' Monahan deemed the cutting-edge tech particularly crucial. 'This study shows how we can leverage the next generation of satellite Earth observation technologies to study these processes,' he said.
