Latest news with #tsunamis
CTV News
19-07-2025
- Science
- CTV News
Scientists confirm megathrust quake danger exists not only in southern B.C., but also in the north
The potential for large quakes and tsunamis off the south coast has long been known, but now scientists are confirming another theory in the north of the provin The potential for large quakes and tsunamis off the south coast has long been known, but now scientists are confirming another theory in the north of the province. Following years of debate, scientists can now confirm that a fault zone off B.C.'s northern coast is capable of producing powerful megathrust earthquakes, the kind that can generate tsunamis. The findings reveal what many researchers theorized: That the Pacific Plate is partially dipping beneath the North American Plate. This comes more than a decade after a powerful 7.8-magnitude quake struck near Haida Gwaii, on Oct. 27, 2012. At the time, scientists were puzzled by the quake's characteristics because it resembled activity normally seen much further south, in the Cascadia Subduction Zone off Vancouver Island and Washington State. The 2012 quake had a thrust mechanism which was not typical of the Queen Charlotte Fault, where plates usually slide past each other horizontally. 'So not just sliding, but also going a bit under North America,' said Mladen Nedimovic, a professor of Earth and Environmental Sciences at Dalhousie University. The research team used a state-of-the-art, 15-kilometre-long hydrophone streamer. Essentially, a very long wire with thousands of underwater microphones attached. They then scoured the fault from northern B.C. to southern Alaska. The breakthrough will allow researchers to better predict what types of earthquakes to expect. 'They're both large,' Nedimovic explained. 'But the ones where one plate pushes under another are the type that can produce tsunamis.' Scientists still can't predict exactly when a quake might hit, but the findings will help governments better prepare. 'It's not just about saving lives, but also about protecting critical infrastructure,' he added. The findings have been published in the journal Science Advances, and included research from Canadian and American scientists, including from Dalhousie University in Halifax.
Yahoo
15-06-2025
- Science
- Yahoo
Tectonic plates can spread subduction like a contagion — jumping from one oceanic plate to another
When you buy through links on our articles, Future and its syndication partners may earn a commission. Subduction zones, where one tectonic plate dives underneath another, drive the world's most devastating earthquakes and tsunamis. How do these danger zones come to be? A study in Geology presents evidence that subduction can spread like a contagion, jumping from one oceanic plate to another — a hypothesis previously difficult to prove. This result "is not just speculation," says University of Lisbon geologist João Duarte, who was not involved in the research. "This study builds an argument based on the geological record." Because subduction drags crust deep into the earth, its beginnings are hard to examine. The new study provides a rare ancient example of potential subduction "infection." Its authors say they've discovered evidence that neighboring collisions triggered East Asia's "Ring of Fire," a colossal subduction system currently fueling earthquakes and volcanoes from Alaska to the southern Indian Ocean. Nearly 300 million years ago China was a scattering of islands separated by the ancient Tethys and Asian oceans. Established subduction zones consumed these oceans, welding the landmasses into a new continent and raising mountains from Turkey to China. By 260 million years ago this subduction seems to have spread and begun pulling down the neighboring Pacific plate. "The dying act of those closing oceans may have been to infect the Pacific plate and start it subducting westward under the Asian continent," says study lead author Mark Allen, a geologist at Durham University in England. "In one form or another, it's been diving down ever since." The smoking gun in this case is the "Dupal anomaly," identified by a geochemical fingerprint from the ancient Tethys Ocean and what is now the Indian Ocean. When the study authors unexpectedly found this signature in volcanic rocks from the western Pacific, they surmised that material from the Tethys had spread eastward across a plate boundary from one subduction zone to another — triggering the neighboring plate's descent. "It's like seeing someone's fingerprint at a crime scene," Allen says. RELATED STORIES —Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests —Gigantic 'mud waves' buried deep beneath the ocean floor reveal dramatic formation of Atlantic when Africa and South America finally split —Yosemite's ultra-deep canyon may have been carved in part by a ghost volcano and river, provocative research suggests But the mechanism of spread remains mysterious. The researchers suspect that transform faults — boundaries where plates slide past one another, like the San Andreas Fault — may act as weak spots where slight changes in collision angle or speed can destabilize dense oceanic crust, causing it to sink. Duarte compares the scenario to aluminum foil in water. "The foil floats," he says, "but the slightest tap will cause it to sink." If subduction spreads this way, could the Atlantic Ocean's relatively quiet plate margins be next? The massive 1755 Lisbon earthquake hints at early subduction invasion there. Duarte suggests parts of Iberia and the Caribbean are undergoing this process's initial stages: "In another 100 million years a new Atlantic 'Ring of Fire' may form — just as it once did in the Pacific." This article was first published at Scientific American. © All rights reserved. Follow on TikTok and Instagram, X and Facebook.
BBC News
07-06-2025
- 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.
Gizmodo
03-06-2025
- 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.
