Latest news with #tectonicplates
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.
News24
20-07-2025
- Climate
- News24
Tsunami alert after powerful quakes strike off coast of Russia
A series of powerful earthquakes struck off the coast of Russia's far east on Sunday, triggering a tsunami alert, the US Geological Survey said. Earlier 5.0-magnitude and 6.7-magnitude earthquakes did not initially trigger a tsunami alert, but were followed by a 7.4-magnitude quake at 08:49, prompting the USGS to warn that 'hazardous tsunami waves are possible'. It said the tsunami alert zone applied for coastal areas within a radius of 300 kilometres (186 miles) of the epicentre in the Pacific Ocean, off the city of Petropavlovsk-Kamchatsky. The state of Alaska sits across the Bering Sea from the city, but no US territory appeared to be in the alert zone. The initial earthquakes were followed by several aftershocks, including another 6.7-magnitude quake, said USGS. The epicentre was around 140 kilometres east of Petropavlovsk-Kamchatsky, capital of the Kamchatka region. The Kamchatka peninsula is the meeting point of the Pacific and North American tectonic plates, making it a seismic hot zone. Since 1900, seven major earthquakes of magnitude 8.3 or higher have struck the area.
CNN
04-07-2025
- Business
- CNN
An ambitious vision of a city built from lava
Erupting from fiery volcanoes, lava has historically been an uncontrollable force that destroys buildings and neighborhoods in its wake. But what if that force could instead be redirected and harnessed to create whole cities? An ambitious project from Icelandic firm arkitektar, presented at this year's Venice Architecture Biennale (running until November 23), proposes just that. Whereas lava naturally cools on the landscape to become volcanic rock such as basalt, 'Lavaforming' — which envisions molten rock as a new form of building material — lays out strategies for cooling it in controlled ways so that it can set into walls, columns and other architectural elements capable of producing new settlements. Along with collaborators, arkitektar has made a film imagining the year 2150, when such building technology could become a reality, reshaping the world in the process. Founded by Arnhildur Pálmadóttir and operated with her son Arnar Skarphéðinsson, arkitektar has been undertaking research and conducting tests to explore how something that is seen primarily as a threat can be transformed into a renewable resource capable of producing sustainable buildings. But just how realistic is the future of lava cities? Iceland is one of the most active volcanic regions in the world, situated on a rift between two tectonic plates. Home to around 30 volcano systems, the country on average experiences an eruption every five years. It was during one such occurrence — the 2014 Holuhraun eruption — that Pálmadóttir realized there was a 'huge amount of material coming up from the ground,' she explained over video call from the capital Reykjavík. She thought: 'wow, we could build a whole city in one week with that.' The 'Lavaforming' project started in earnest a few years later as a 'thought experiment,' added Skarphéðinsson. It also aimed to be a critique of the building industry's reliance on concrete and the carbon emissions resulting from its production. (It is estimated that due to heating lime and clay at high temperatures to create cement, a key ingredient of concrete, the material's production accounts for approximately 8% of global CO2 emissions, which contribute to global warming and climate degradation.) 'We think that lava can compete with concrete, but be more sustainable,' said Pálmadóttir, adding that lava 'has all the materialities that concrete has, depending on how it cools down.' If lava cools quickly, explained Pálmadóttir, it turns into a hard, glass-like material — obsidian. If it cools slowly, it is more likely to crystallize, which can work well for creating columns and structural elements. If the lava cools quickly and also gets air in it, meanwhile, a pumice-like, highly insulative material is created. The carbon emitted by hot lava spewing from a volcano would be released into the atmosphere anyway, she said, no matter how it is cooled and used — so better to make the most of it and avoid additional emissions from concrete production. arkitektar has put forward three speculative methods for turning lava into architecture. In the first, carefully designed networks of trenches are dug at the foot of active volcanoes for molten lava from eruptions to be directed into, where it can cool to create structural walls or foundations for a city; such trenches could also channel lava into a factory that molds the lava into bricks that can be moved and used elsewhere. The hope is that by redirecting the lava into trenches, surrounding communities would also be protected from the damaging force of the lava during an eruption. The second method harnesses the technology of 3D printing, imagining future 3D-printing robots which could traverse a landscape of molten lava after an eruption and use the lava to 'print' elements of buildings. The technology for such robots does not yet exist, however. The third technique involves tapping into magma under the ground, directing lava into new, specially constructed chambers where it could cool into prefabricated, replicable architectural elements. The team believes accessing such subterranean magma would take a similar approach to that of geothermal energy production — which harnesses heat from the Earth's core and is a significant source of energy in Iceland. Though, arkitektar do not yet know if such a process would be geologically safe. The architects concede that the practicalities of 'Lavaforming' are not yet fully worked out and relies on further research and technological development, not to mention wider buy-in. But they feel their proposal is becoming more realistic as the project evolves. Since the project's launch in 2022, arkitektar have increasingly engaged with scientists, who have worked on lava flow prediction models and visualized them in 3D software, making lava flow simulations for eruptions in Iceland and undertaking 'lava tests' in which volcanic rock is heated to become molten lava again, and cooled in controlled ways to make prototype building elements. Relying on eruptions anchors the proposal to time and place, but believes its idea could have value in volcanically active Iceland, as well as other locations where there is 'slow-flowing lava,' said Pálmadóttir, adding that Hawaii is 'really similar' to Iceland geologically, as are the Canary Islands in the Atlantic Ocean. Volcanic rock is not a new building material — it has been used throughout time, like stone, for structural elements such as walls. It can be found all over the world, and once quarried, is used as stackable rocks, bricks, panels, or crushed into gravel to be used as aggregate in concrete. Basalt, the most common volcanic rock, has been used to build structures including the 13th-century Qasr al-Azraq ('Blue Fortress') in Jordan, the 15th-century Château d'Anjony in France, the Gateway of India (1924) in Mumbai, and the Herzog & de Meuron-designed Dominus Winery (1997) in Napa Valley, California. More recently, basalt was used in the Nashan Geological Museum (2021) in Yangzhou, China, the Radisson Resort & Spa (2023) in Lonavala, India, and an impressive private home called Casa Basaltica (2023) in Querétaro, Mexico. Architects appreciate the material for its strength, durability, insulating properties, rugged texture and often dark tones. The way wants to use volcanic rock, however, is very different — and relies on working with it in its molten state. The practice wants to harness lava as a 'mono material,' cooling it in controlled and varied ways — which has 'never been done before,' said Skarphéðinsson — to achieve different material qualities within one single form, from solid blocks to pumice-like insulative stone and glass-like sheets for windows. Much of inspiration stems from nature, which, as Pálmadóttir said, 'has been creating forms and structures out of lava from the beginning of time.' She references the caves formed by bubbles in lava after an 18th-century eruption on the island of Lanzarote (part of the Canary Islands), which 20th-century architect César Manrique used as subterranean rooms for his own home in 1968. Whether we end up living in cities made of lava relies on complicated practical factors, from technology and safety to funding and political appetite. But for now, vision is simply to make people think a little differently. 'How can we change systems to respond to the global (climate) emergency?' asked Pálmadóttir. 'How does architecture and the built environment need to address this differently? We hope other places will look at this project as an inspiration.'
Yahoo
27-06-2025
- Science
- Yahoo
'Pulsing, like a heartbeat': Rhythmic mantle plume rising beneath Ethiopia is creating a new ocean
When you buy through links on our articles, Future and its syndication partners may earn a commission. Rhythmic pulses of molten rock are rising beneath eastern Africa, according to a new study. The pulsing plume of hot mantle beneath Ethiopia, driven by plate tectonics, is slowly pulling the region apart and forming a new ocean near the Gulf of Aden and the Red Sea, researchers reported June 25 in the journal Nature Geoscience. "We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above," Derek Keir, an Earth scientist at the University of Southampton and the University of Florence, said in a statement. "This has profound implications for how we interpret surface volcanism, earthquake activity, and the process of continental breakup." The mantle plume lies under Ethiopia's Afar region, at the intersection of three tectonic plates. All of the rifts between these plates are different ages, and they are changing at different rates; some are in the process of forming new oceans, while others are pulling apart the crust beneath Africa. But the structure and motion of the plume, as well as the forces driving these movements, aren't well understood. To investigate the structure of the crust and the mantle plume beneath it, the scientists studied the chemical compositions of more than 130 samples of volcanic rocks from the Afar region. These samples provided information about the depth and composition of melted rock beneath the surface. The team also used computer models to determine how the region might respond to different kinds of mantle plumes and compared those responses to existing geological data. A single mantle plume lies beneath all three rifts, the researchers found, but its chemical composition is not uniform. Further, the molten rock surges upward rhythmically, leaving behind distinct chemical signatures. "The chemical striping suggests the plume is pulsing, like a heartbeat," Tom Gernon, an Earth scientist at the University of Southampton, said in the statement. "These pulses appear to behave differently depending on the thickness of the plate, and how fast it's pulling apart. In faster-spreading rifts like the Red Sea, the pulses travel more efficiently and regularly like a pulse through a narrow artery." RELATED STORIES —Study reveals 'flawed argument' in debate over when plate tectonics began —There's a 'ghost' plume lurking beneath the Middle East — and it might explain how India wound up where it is today —Africa is being torn apart by a 'superplume' of hot rock from deep within Earth, study suggests Varying spacing between the stripes in different rifts suggests that the mantle plume responds differently depending on the tectonic plates above. In places where the lithosphere — the crust and upper mantle — is thicker, the mantle flow is impeded, and the striping is more condensed. Under a thinner lithosphere, the stripes are more spread out. The findings could help scientists understand volcanic activity at the surface. "The work shows that deep mantle upwellings can flow beneath the base of tectonic plates and help to focus volcanic activity to where the tectonic plate is thinnest," Keir said in the statement. Future work in the Afar region could involve investigating the rate of mantle flow beneath the various plates, Keir added.
The Independent
25-06-2025
- Science
- The Independent
Something is ‘pulsing' beneath the Earth, scientists say – and it could tear a continent apart
Scientists have detected deep pulses in the Earth beneath Africa – and it could tear the continent apart. The pulses are made up of molten mantle rock surging in rhythm, the researchers say. The plume of hot mantle is surging upwards in pulses that are like a heartbeat, they say. Eventually, the continent will be torn apart and a new ocean will be formed. That will take place over millions of years, as the tectonic plates are ripped apart at rift zones like those in the Afar region in Ethiopia. That is where scientists found the evidence of the unexpected behaviour. 'We found that the mantle beneath Afar is not uniform or stationary – it pulses, and these pulses carry distinct chemical signatures,' said Emma Watson, the scientist who led the study. 'These ascending pulses of partially molten mantle are channelled by the rifting plates above. That's important for how we think about the interaction between Earth's interior and its surface.' In the research, scientists gathered samples from the Afar region, where three tectonic rifts meet. Scientists have long thought that mantle was being pushed up making the crust extend, eventually giving birth to a new ocean basin, but did not know how it was happening. To better understand that process, they took those samples and combined them with existing data and models to understand the plume beneath the surface of the Earth. They showed that there is one asymmetric plume beneath the surface. 'We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above. This has profound implications for how we interpret surface volcanism, earthquake activity, and the process of continental breakup,' said Derek Keir, a co-author. 'The work shows that deep mantle upwellings can flow beneath the base of tectonic plates and help to focus volcanic activity to where the tectonic plate is thinnest. Follow on research includes understanding how and at what rate mantle flow occurs beneath plates,' The work is described in a new paper, 'Mantle upwelling at Afar triple junction shaped by overriding plate dynamics', published in the journal Nature Geoscience.
