Latest news with #TheSeismicRecord
Yahoo
7 days ago
- Science
- Yahoo
In world first, CCTV captures supershear velocity earthquake
Yahoo is using AI to generate takeaways from this article. This means the info may not always match what's in the article. Reporting mistakes helps us improve the experience. Yahoo is using AI to generate takeaways from this article. This means the info may not always match what's in the article. Reporting mistakes helps us improve the experience. Yahoo is using AI to generate takeaways from this article. This means the info may not always match what's in the article. Reporting mistakes helps us improve the experience. Generate Key Takeaways Earthquakes are violent events that alter the face of the planet. In many cases, those changes occur beneath the surface and only gradually become visible over thousands of years. Occasionally, however, an earthquake's effects aren't just felt—they're seen. It's even rarer to actually capture one of those moments on camera, but according to seismologists at Japan's Kyoto University, the footage highlights the first-known video of a strike-slip fault. Their analysis, published in The Seismic Record, has led to new findings based on real-time visual evidence of tectonic motion. The magnitude 7.7 event took place on March 28 along the Sagaing Fault with an epicenter near Myanmar's second-largest city, Mandalay. Although the initial rupture process lasted barely 80 seconds, it and numerous aftershocks were ultimately responsible for 5,456 confirmed deaths and over 11,000 injuries. Later evaluations indicated the quake was the second deadliest in modern history, as well as the most powerful to hit Myanmar in over a century. According to a separate group's paper published in the same journal, the southern portion of the rupture occurred at an astonishing 3.7 miles per second—fast enough to qualify as 'supershear velocity.' Amid the catastrophe, an outdoor CCTV camera about 74.5 miles south of the epicenter recorded a visceral illustration of its power. Over just a few moments, what at first looks like a single chunk of the ground appears to suddenly divide and horizontally shift past one another in opposite directions. Completely by accident, the camera recorded a direct look of a strike-slip fault, something previously analyzed by remote seismic instruments. To researchers at Kyoto University, the clip wasn't just a jaw-dropping scene—it was an opportunity to study a strike-slip fault using visual data. Geologists analyzed the brief video frame-by-frame to learn about the fault shift. Credit: KyotoU / Jesse Kearse 'We did not anticipate that this video record would provide such a rich variety of detailed observations,' corresponding author and geologist Jesse Kearse said in a statement. 'Such kinematic data is critical for advancing our understanding of earthquake source physics.' Kearse and colleagues utilized a technique called pixel cross-correlation to analyze the fault movement on a frame-by-frame basis. Their findings showed the fault slipped horizontally by 8.2 feet in only 1.3 seconds, with a maximum speed of about 10.5 feet per second. While the movement matched experts' existing knowledge of strike-slip ruptures, the short duration and speed were new developments. 'The brief duration of motion confirms a pulse-like rupture, characterized by a concentrated burst of slip propagating along the fault, much like a ripple traveling down a rug when flicked from one end,' Kearse explained. Additional examinations also proved that the slip path was slightly curved, confirming previous observations recorded elsewhere in the world. This means subtly curving strike-slips instead of totally linear ones may be the rule, not the exception. 'Overall, these observations establish a new benchmark for understanding dynamic rupture processes,' the study's authors wrote, adding that the video offers real-time confirmation of curved slip paths while helping 'deepen our understanding of the physical mechanisms that control rapid fault slip during large earthquakes.' Such discoveries may also help seismologists, geologists, and urban planners design more resilient architecture to ensure that when major earthquakes inevitably occur, their damage is minimized as much as possible.
Gizmodo
21-07-2025
- Science
- Gizmodo
Myanmar's Devastating Earthquake in March Split the Earth at ‘Supershear Velocity'
On March 28, Myanmar was rocked by a 7.8 magnitude earthquake that claimed over 5,000 lives and caused damage even in neighboring countries. In a study published July 10 in The Seismic Record, seismologists confirmed previous research indicating that the southern part of the large earthquake's rupture, or fracture, took place at astounding speeds of up to between 3.1 and 3.7 miles per second (5 to 6 kilometers per second)—at supershear velocity. This likely played a role in the earthquake's devastating impact. When an earthquake strikes, the first seismic waves to propagate from the epicenter are P waves, fast-moving waves that compress their way through all kinds of material but do not cause a lot of damage. Then come the S waves, or shear waves, which are slower but cause highly destructive perpendicular motion. Simply put, when parts of an earthquake's fault rupture at supershear velocity, it means that the speed of the break along a particular stretch of the rupture was faster than the speed of its S waves. In moderate earthquakes, rupture velocities are usually between 50 and 85% of S-wave velocity. Myanmar's earthquake occurred along the Sagaing Fault, which runs north-south through Myanmar. The fault is strike-slip, meaning two tectonic plates slide horizontally against each other. The Sagaing Fault's strike-slip movement in March was clearly captured in potentially first-of-its-kind footage showcasing an expanse of land suddenly moving forward relative to the viewer. The natural disaster saw around 298.3 miles (480 km) of the Sagaing Fault rupture or 'slip,' which is extremely long for a strike-slip rupture of this magnitude, according to the seismologists. By studying seismic and satellite imagery, they determined that the rupture had 'large slip of up to 7 m [23 feet] extending ∼85 km [52.8 miles] north of the epicenter near Mandalay, with patchy slip of 1–6 m [3.3–19.7 feet] distributed along ∼395 km [245.4 miles] to the south, with about 2 m [6.6 ft] near the capital Nay Pyi Taw.' A seismic station near Nay Pyi Taw registered ground motion data that were 'immediately convincing of supershear rupture given the time between the weak, dilational P wave first arrival and the arrival of large shear offset of the fault' at the station, UC Santa Cruz's Thorne Lay said in a Seismological Society of America statement. An offset is the ground displacement that occurs along a fault during an earthquake. 'That was unusually clear and convincing evidence for supershear rupture relative to other long strike-slip events that I have worked on.' The Sun Might Be Influencing Earthquakes, Scientists Say Lay and his colleagues suggest that the supershear velocity, as well as the rupture's strong directivity (the piling up of S waves in the direction of the fault line as the rupture spreads) toward the south, might have caused the earthquake's widespread damage. While the Sagaing Fault frequently causes large earthquakes, the one in March involved a stretch of the fault between the cities of Mandalay and Nay Pyi Taw that has been quiet since 1912. 'Longer histories and better understanding of fault segmentation and geometry are needed to have any guidance for future event activity, but I would not expect the central area to fail again before a long period of rebuilding strain energy,' Lay added. While it is impossible to predict earthquakes with any kind of precision, earthquake early-warning (EEW) systems provide last-minute but still crucial warnings of incoming seismic events by sending out electronic alerts that travel faster than seismic waves. While many seismic regions don't have the necessary infrastructure for such systems, the smartphone-based Android Earthquake Alerts (AEA) system has recently proved to be as efficient as traditional seismic networks.
