May 2022

Ancient Massive 'Dragon of Death' Flying Reptile Dug Up in Argentina

Ancient Massive 'Dragon of Death' Flying Reptile Dug Up in Argentina

Ancient Massive 'Dragon of Death' Flying Reptile Dug Up in Argentina. Life reconstruction of Thanatosdrakon amaru. Image credit: Uni...

How The World’s Most Active Volcano Was Born

Hawaii, Tectonic, volcano 7:55 PM

How The World’s Most Active Volcano Was Born

(USGS photo by J.M. Chang) A new international study led by Monash University has described for the first time what may have triggered the...

High Resolution Imaging Reveals Puzzling Features Deep in Earth’s Interior

Earth News, Geology, Tectonic 8:48 PM

<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA_bo_VZBuivFP0qUsvAueNtbSB46d1JxRGufW3RLiqQBE-Rn_n6uqzf5PcG9ZhY8Ip0njefLq4xu6epBlOgs-twqqoCVQtFLQxxJx6-K-8YD2n0EEHR1ZjjZzf2Bteeuj15gc64tC05jsBhtRrTQGqPknfD1hUEMOS6sQHsz9YjEJRUgPUIiCq_sz/s1207/Hawaiian-Ultra-Low-Velocity-Zone-ULVZ-Structure%20(1).jpg" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="540" data-original-width="1207" height="286" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiA_bo_VZBuivFP0qUsvAueNtbSB46d1JxRGufW3RLiqQBE-Rn_n6uqzf5PcG9ZhY8Ip0njefLq4xu6epBlOgs-twqqoCVQtFLQxxJx6-K-8YD2n0EEHR1ZjjZzf2Bteeuj15gc64tC05jsBhtRrTQGqPknfD1hUEMOS6sQHsz9YjEJRUgPUIiCq_sz/w640-h286/Hawaiian-Ultra-Low-Velocity-Zone-ULVZ-Structure%20(1).jpg" title="Conceptual cartoons of the Hawaiian ultra-low velocity zone (ULVZ) structure. A)" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Conceptual cartoons of the Hawaiian ultra-low velocity zone (ULVZ) structure. A) ULVZ on the core–mantle boundary at the base of the Hawaiian plume (height is not to scale). B) a zoom in of the modeled ULVZ structure, showing interpreted trapped postcursor waves (note that the waves analyzed have horizontal displacement). Credit: Nature Communications, </td></tr></tbody></table>  New research led by the University of Cambridge is the first to take a detailed image of an unusual pocket of rock at the boundary layer with Earth's core, some three thousand kilometres beneath the surface. The enigmatic area of rock, which is located almost directly beneath the Hawaiian Islands, is one of several ultra-low velocity zones -- so-called because earthquake waves slow to a crawl as they pass through them. The research, published today in Nature Communications, is the first to reveal the complex internal variability of one of these pockets in detail, shedding light on the landscape of Earth's deep interior and the processes operating within it. "Of all Earth's deep interior features, these are the most fascinating and complex. We've now got the first solid evidence to show their internal structure -- it's a real milestone in deep earth seismology," said lead author Zhi Li, PhD student at Cambridge's Department of Earth Sciences. <div style="margin: 0px auto; width: 100%;">
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</div> Earth's interior is layered like an onion: at the centre sits the iron-nickel core, surrounded by a thick layer known as the mantle, and on top of that a thin outer shell -- the crust we live on. Although the mantle is solid rock, it is hot enough to flow extremely slowly. These internal convection currents feed heat to the surface, driving the movement of tectonic plates and fuelling volcanic eruptions. Scientists use seismic waves from earthquakes to see beneath Earth's surface -- the echoes and shadows of these waves revealing radar-like images of deep interior topography. But until recently, images of the structures at the core-mantle boundary, an area of key interest for studying our planet's internal heat flow, have been grainy and difficult to interpret. The researchers used the latest numerical modelling methods to reveal kilometre-scale structures at the core-mantle boundary. According to co-author Dr Kuangdai Leng, who developed the methods while at the University of Oxford, "We are really pushing the limits of modern high-performance computing for elastodynamic simulations, taking advantage of wave symmetries unnoticed or unused before." Leng, who is currently based at the Science and Technology Facilities Council, said that this means they can improve the resolution of the images by an order of magnitude compared to previous work. They observed a 40% reduction in the speed of seismic waves travelling at the base of the ultra-low velocity zone beneath Hawaii. According to the authors, this supports existing proposals that the zone contains much more iron than the surrounding rocks -- meaning it is denser and more sluggish. "It's possible that this iron-rich material is a remnant of ancient rocks from Earth's early history or even that iron might be leaking from the core by an unknown means," said project lead, Dr Sanne Cottaar from Cambridge Earth Sciences. The new research could also help scientists understand what sits beneath and gives rise to volcanic chains like the Hawaiian Islands. Scientists have started to notice a correlation between the location of the descriptively-named hotspot volcanoes, which include Hawaii and Iceland, and the ultra-low velocity zones at the base of the mantle. The origin of hotspot volcanoes has been widely debated, but the most popular theory suggests that plume-like structures bring hot mantle material all the way from the core-mantle boundary to the surface. With images of the ultra-low velocity zone beneath Hawaii now in hand, the team can also gather rare physical evidence from what is likely the root of the plume feeding Hawaii. Their observation of dense, iron-rich rock beneath Hawaii would support surface observations, "Basalts erupting from Hawaii have anomalous isotope signatures which could either point to either an early-Earth origin or core leaking, it means some of this dense material piled up at the base must be dragged to the surface," said Cottaar. More of the core-mantle boundary now needs to be imaged to understand if all surface hotspots have a pocket of dense material at the base. Where and how the core-mantle boundary can be targeted does depend on where earthquakes occur, and where seismometers are installed to record the waves. The team's observations add to a growing body of evidence that Earth's deep interior is just as variable as it's surface. "These low velocity zones are one of the most intricate features we see at extreme depths -- if we expand our search we are likely to see ever-increasing levels of complexity, both structural and chemical, at the core-mantle boundary," said Li. They now plan to apply their techniques to enhance the resolution of imaging of other pockets at the core-mantle boundary, as well as mapping new zones. Eventually they hope to map the geological landscape across the core-mantle boundary and understand its relationship with the dynamics and evolutionary history of our planet. The above story is based on <a href="https://www.cam.ac.uk/research/news/scientists-see-puzzling-features-deep-in-earths-interior" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"> provided by <a href="https://www.cam.ac.uk/" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">University of Cambridge</a><span face=""Helvetica Neue", Helvetica, Arial, sans-serif" style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline; float: none; font-size: 14px; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;">.

High Resolution Imaging Reveals Puzzling Features Deep in Earth’s Interior

Conceptual cartoons of the Hawaiian ultra-low velocity zone (ULVZ) structure. A) ULVZ on the core–mantle boundary at the base of the Hawaiia...

Alive 830-Million-Year-Old Organisms Found Trapped in Ancient Rock

Earth History, Researches 8:47 PM

Alive 830-Million-Year-Old Organisms Found Trapped in Ancient Rock

Alive 830-Million-Year-Old Organisms Found Trapped in Ancient Rock. Distribution of microorganisms in primary fluid inclusions in Browne For...

Taiwan’s Crust Is Moving at ‘Extreme’ Speed

Earth News, Geology, Tectonic 8:41 PM

<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0fS-QIaMdKc1JA0p_Y_G-ZCaJtUM1ui9B0PPS_5CX-5zfN6-dhiY3MWX_uY4Np3N17bxoZ7T0yXsl-tOMr68Nbw66wLwrDxkcay7zE0nlRiMBeVBtAbwzswTNU1TaPk1Z0dJKqoyNKSP432jgVObjydcCgUYkmq2x9lmno24h0XyKbuD5QV-8GyJO/s1024/Taiwan%E2%80%99s%20Crust%20Is%20Moving%20at%20%E2%80%98Extreme%E2%80%99%20Speed%20(1).jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="683" data-original-width="1024" height="426" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0fS-QIaMdKc1JA0p_Y_G-ZCaJtUM1ui9B0PPS_5CX-5zfN6-dhiY3MWX_uY4Np3N17bxoZ7T0yXsl-tOMr68Nbw66wLwrDxkcay7zE0nlRiMBeVBtAbwzswTNU1TaPk1Z0dJKqoyNKSP432jgVObjydcCgUYkmq2x9lmno24h0XyKbuD5QV-8GyJO/w640-h426/Taiwan%E2%80%99s%20Crust%20Is%20Moving%20at%20%E2%80%98Extreme%E2%80%99%20Speed%20(1).jpg" title="Taiwan’s Crust Is Moving at ‘Extreme’ Speed" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">Photo: © University of Oregon </td></tr></tbody></table>  A new study finds evidence of surprisingly rapid upward movement of earth’s crust on the island of Taiwan. Over roughly half a million years, the Coastal Range of east Taiwan was rising at a rate of 9 to 14 millimeters per year, the research shows. Over roughly half a million years, the Coastal Range of east Taiwan was rising at a rate of 9 to 14 millimeters (0.35 to 0.55 inches) per year, the research shows While this seems imperceptibly slow, it’s quite fast for mountains. Much of the dramatic topography on the surface of the planet is formed by vertical movements of less than a millimeter per year. “The Earth’s surface can act extremely fast, way faster than most people imagine,” says Larry Syu-Heng Lai, a doctoral student who led the work alongside researchers at the University of Oregon and a team of collaborators in Taiwan. “These measurements of extreme rates are unprecedented, and the records challenge ideas about the long timescales—several million years—needed for the rise and fall of a mountain.” 33<div style="width:100%;margin: 0px auto">
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</div> Taiwan sits at the boundary of two tectonic plates and formed over time from a series of collisions between the plates. Mountain-building happens there due to intense deformation and movement of the rocks near Earth’s surface. Geologists have many ways to estimate the age of rocks and reconstruct their movement over time. But this rapid vertical crust movement in Taiwan had gone undetected by more traditional techniques. To get a new look, Lai and his colleagues analyzed sedimentary rocks from sites around Taiwan. These rocks record the history of sediment accumulation and erosion as the crust moves up and down. The researchers looked at tiny fossils embedded in those layers of rocks to figure out when they formed. They also looked at magnetic properties of the rocks, signatures left behind by flips in the direction of the Earth’s magnetic pole over geologic history. By combining all of those clues, they pieced together a new story. Taiwan is in a geological zone where volcanic islands from an oceanic plate are crushing together and merging into a continent. The surface of the volcanic crust can bounce up and down dramatically, up to 10 kilometers (6.2 miles) of displacement, due to interactions between the plates. From that displacement, Lai and his team calculated the unexpectedly fast rate at which the mountains were rising. Their discoveries also challenge a long-standing hypothesis for the geological origin story of Taiwan. Previously, geologists thought that Taiwan’s mountains emerged gradually along the boundary of the two plates, from north to south, over five to six million years. “Our new idea says differently; the whole Coastal Range is popping up at the same time along the plate boundary, within half a million years,” Lai says. “We need to rethink about what was really happening during this mountain-building event and how to reconcile and reinterpret data from earlier research.” Researchers could also use the analysis techniques to understand how geological processes interact with processes like climate change and erosion to shape the landscape. While the research focused on a specific part of Taiwan, dramatic movements like these also could have helped shape places like the Talkeetna-Chugach Mountains in Alaska and Klamath Mountains in Oregon. “These kinds of crust motions are probably underdetected by previous studies,” Lai says.  The above story is based on <a href="https://around.uoregon.edu/content/scientists-are-amazed-how-fast-taiwans-crust-moving" rel="nofollow" target="_blank">materials </a>provided by the <a href="https://www.uoregon.edu/" rel="nofollow" target="_blank">University of Oregon.</a>

Taiwan’s Crust Is Moving at ‘Extreme’ Speed

Photo: © University of Oregon A new study finds evidence of surprisingly rapid upward movement of earth’s crust on the island of Taiwan. O...

Weird 'Yellow Brick Road' Discovered at Bottom of the Ocean

Earth News, ocean, Researches 8:09 PM

Weird 'Yellow Brick Road' Discovered at Bottom of the Ocean

Weird 'Yellow Brick Road' Discovered at Bottom of the Ocean. A deep-sea 'yellow brick road'. (Photo: The Ocean Exploration T...

City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet

Antarctic, climate, Earth News 8:13 PM

<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOACp6dCdO6eeKFcdH9ZKZMYyCyZJQ-DFmGDOvsdGBCb62QMZO4xAaKVP60KyBFQholaKeQkuNZqRhzl-jaS9fkDKao6UmaA1liDuoIbOkmN32CZEfpYnE7WJa1PM0XLinCYJ2TKF5h4krwCrGsGa1uyeJTBH1uZY1IjZCyp_RM_uQPmR6DRKA6jro/s1200/The%20coast%20of%20Antarctica%20near%20where%20the%20East%20Antarctic%20Ice%20Sheet%20meets%20the%20sea%20(1).jpg" style="margin-left: auto; margin-right: auto;"><img alt="City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet" border="0" data-original-height="800" data-original-width="1200" height="426" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiOACp6dCdO6eeKFcdH9ZKZMYyCyZJQ-DFmGDOvsdGBCb62QMZO4xAaKVP60KyBFQholaKeQkuNZqRhzl-jaS9fkDKao6UmaA1liDuoIbOkmN32CZEfpYnE7WJa1PM0XLinCYJ2TKF5h4krwCrGsGa1uyeJTBH1uZY1IjZCyp_RM_uQPmR6DRKA6jro/w640-h426/The%20coast%20of%20Antarctica%20near%20where%20the%20East%20Antarctic%20Ice%20Sheet%20meets%20the%20sea%20(1).jpg" title="The coast of Antarctica near where the East Antarctic Ice Sheet meets the sea. Credit: Shuai Yan/UT Jackson School of Geosciences" width="640" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet. The coast of Antarctica near where the East Antarctic Ice Sheet meets the sea. Credit: Shuai Yan/UT Jackson School of Geosciences</td></tr></tbody></table> Scientists investigating the underside of the world's largest ice sheet in Antarctica have discovered a city-size lake. The lake, called Lake Snow Eagle, lies in a mile-deep canyon in the highlands of Antarctica's Princess Elizabeth Land, a few hundred miles from the coast. Scientists investigating the underside of the world's largest ice sheet in East Antarctica have discovered a city-size lake whose sediments might contain a history of the ice sheet since its earliest beginnings. That would answer questions about what Antarctica was like before it froze, how climate change has affected it over its history, and how the ice sheet might behave as the world warms. Revealed by heavily instrumented polar research aircraft, Lake Snow Eagle is covered by 2 miles of ice and lies in a mile-deep canyon in the highlands of Antarctica's Princess Elizabeth Land, a few hundred miles from the coast. "This lake is likely to have a record of the entire history of the East Antarctic Ice Sheet, its initiation over 34 million years ago, as well as its growth and evolution across glacial cycles since then," said polar expert Don Blankenship, one of the paper's authors and a senior research scientist at The University of Texas at Austin's Institute for Geophysics. "Our observations also suggest that the ice sheet changed significantly about 10,000 years ago, although we have no idea why." <div style="margin: 0px auto; width: 100%;">
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</div> Because it lies relatively close to the coast, researchers think that Lake Snow Eagle might contain information about how the East Antarctic Ice Sheet first began and the part played by the Antarctic Circumpolar Current, a ring of cold water circling the continent that scientists think is responsible for keeping it cool. The first hint that the lake and its host canyon existed emerged when scientists spotted a smooth depression on satellite images of the ice sheet. To confirm it was there, researchers spent three years flying systematic surveys over the site with ice penetrating radar and sensors that measure minute changes in Earth's gravity and magnetic field. "I literally jumped when I first saw that bright radar reflection," said the paper's lead author, Shuai Yan, a graduate student at UT Austin's Jackson School of Geosciences who was flight planner for the field research that investigated the lake. What Yan saw was the lake's water that, unlike ice, reflects radar like a mirror. Along with the gravity and magnetic surveys, which lit up the underlying geology of the region and the depth of water and sediments, Yan constructed a detailed picture of a jagged, highland topography with Lake Snow Eagle nestled at the base of a canyon. The newly discovered lake is about 30 miles long, 9 miles wide and 650 feet deep. The sediments at the bottom of the lake are 1,000 feet deep and might include river sediments older than the ice sheet itself. Moving forward, the researchers said getting a sample of the lake's sediments by drilling into it would fill big gaps in scientists' understanding of Antarctica's glaciation and provide vital information about the ice sheet's possible demise from climate change. "This lake's been accumulating sediment over a very long time, potentially taking us through the period when Antarctica had no ice at all, to when it went into deep freeze," said co-author Martin Siegert, a glaciologist at Imperial College London. "We don't have a single record of all those events in one place, but the sediments at the bottom of this lake could be ideal." Lake Snow Eagle was named after one of the aircraft used in its discovery. It is one of many features uncovered by ICECAP-2, an international collaboration to map the last unknown regions of East Antarctica by polar research teams from the U.S., U.K., China, Australia, Brazil and India. The team for this paper included scientists from UTIG, Scripps Institute for Oceanography, Imperial College London, the Australian Antarctic Division, and the Polar Research Institute of China. The research was supported by the G. Unger Vetlesen Foundation and funded by governments and institutions of the countries involved.  The above story is based on <a href="https://news.utexas.edu/2022/05/09/newly-discovered-lake-may-hold-secret-to-antarctic-ice-sheets-rise-and-fall/" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"> provided by <a href="https://www.utexas.edu/" rel="noopener noreferrer nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">University of Texas at Austin</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;">.

City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet

City-Sized Lake Discovered Miles Below The Antarctic Ice Sheet. The coast of Antarctica near where the East Antarctic Ice Sheet meets the se...

Record-Breaking Earthquake Swarm Hits Antarctica as Sleeping Volcano Awakens

Antarctic, Earthquakes 11:55 PM

<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1HDuLZxYaw4RrxRoYtdrcFjTU7oHdRLyHQ4OTxMFPh7zrJ5p4sbe_2Y1CtALS1yt4jCGPBcnY59PIeb4McUEHsPhJ20XkYqSQ9Lysy-azcSuF1C-1nPT8udZ8nR6ufAH31Gfh27C3wQfSc6gwm-BadiHdxjoK6WWyvF-M1VFac7XU-EaS9OPoeAv3/s1200/Record-Breaking%20Earthquake%20Swarm%20Hits%20Antarctica%20as%20Sleeping%20Volcano%20Awakens%20(1).jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="822" data-original-width="1200" height="438" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi1HDuLZxYaw4RrxRoYtdrcFjTU7oHdRLyHQ4OTxMFPh7zrJ5p4sbe_2Y1CtALS1yt4jCGPBcnY59PIeb4McUEHsPhJ20XkYqSQ9Lysy-azcSuF1C-1nPT8udZ8nR6ufAH31Gfh27C3wQfSc6gwm-BadiHdxjoK6WWyvF-M1VFac7XU-EaS9OPoeAv3/w640-h438/Record-Breaking%20Earthquake%20Swarm%20Hits%20Antarctica%20as%20Sleeping%20Volcano%20Awakens%20(1).jpg" title="Record-Breaking Earthquake Swarm Hits Antarctica as Sleeping Volcano Awakens" width="640" /></a></div>  A long-dormant underwater volcano near Antarctica has woken up, triggering a swarm of 85,000 earthquakes. Volcanoes can be found even off the coast of Antarctica. At the deep-sea volcano Orca, which has been inactive for a long time, a sequence of more than 85,000 earthquakes was registered in 2020, a swarm quake that reached proportions not previously observed for this region. The fact that such events can be studied and described in great detail even in such remote and therefore poorly instrumented areas is now shown by the study of an international team published in the journal "Communications Earth and Environment." Led by Simone Cesca from the German Research Centre for Geosciences (GFZ) Potsdam, researchers from Germany, Italy, Poland and the United States were involved. With the combined application of seismological, geodetic and remote sensing techniques, they were able to determine how the rapid transfer of magma from the Earth's mantle near the crust-mantle boundary to almost the surface led to the swarm quake. <h4 style="text-align: left;">The Orca volcano between the tip of South America and Antarctica </h4>Swarm quakes mainly occur in volcanically active regions. The movement of fluids in the Earth's crust is therefore suspected as the cause. Orca seamount is a large submarine shield volcano with a height of about 900 metres above the sea floor and a base diameter of about 11 kilometres. It is located in the Bransfield Strait, an ocean channel between the Antarctic Peninsula and the South Shetland Islands, southwest of the southern tip of Argentina. "In the past, seismicity in this region was moderate. However, in August 2020, an intense seismic swarm began there, with more than 85,000 earthquakes within half a year. It represents the largest seismic unrest ever recorded there," reports Simone Cesca, scientist in GFZ's Section 2.1 Earthquake and Volcano Physics and lead author of the now published study. At the same time as the swarm, a lateral ground displacement of more than ten centimetres and a small uplift of about one centimetre was recorded on neighbouring King George Island. <h4 style="text-align: left;">Challenges of research in a remote area </h4>Cesca studied these events with colleagues from the National Institute of Oceanography and Applied Geophysics -- OGS and the University of Bologna (Italy), the Polish Academy of Sciences, Leibniz University Hannover, the German Aerospace Centre (DLR) and the University of Potsdam. The challenge was that there are few conventional seismological instruments in the remote area, namely only two seismic and two GNSS stations (ground stations of the Global Navigation Satellite System which measure ground displacement). In order to reconstruct the chronology and development of the unrest and to determine its cause, the team therefore additionally analysed data from farther seismic stations and data from InSAR satellites, which use radar interferometry to measure ground displacements. An important step was the modelling of the events with a number of geophysical methods in order to interpret the data correctly. <h4 style="text-align: left;">Reconstructing the seismic events </h4>The researchers backdated the start of the unrest to 10 August 2020 and extend the original global seismic catalog, containing only 128 earthquakes, to more than 85,000 events. The swarm peaked with two large earthquakes on 2 October (Mw 5.9) and 6 November (Mw 6.0) 2020 before subsiding. By February 2021, seismic activity had decreased significantly. The scientists identify a magma intrusion, the migration of a larger volume of magma, as the main cause of the swarm quake, because seismic processes alone cannot explain the observed strong surface deformation on King George Island. The presence of a volumetric magma intrusion can be confirmed independently on the basis of geodetic data. 3<div style="width:100%;margin: 0px auto">
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</div> Starting from its origin, seismicity first migrated upward and then laterally: deeper, clustered earthquakes are interpreted as the response to vertical magma propagation from a reservoir in the upper mantle or at the crust-mantle boundary, while shallower, crustal earthquakes extend NE-SW triggered on top of the laterally growing magma dike, which reaches a length of about 20 kilometres. The seismicity decreased abruptly by mid November, after about three months of sustained activity, in correspondence to the occurrence of the largest earthquakes of the series, with a magnitude Mw 6.0. The end of the swarm can be explained by the loss of pressure in the magma dike, accompanying the slip of a large fault, and could mark the timing of a seafloor eruption which, however, could not yet be confirmed by other data. By modeling GNSS and InSAR data, the scientists estimated that the volume of the Bransfield magmatic intrusion is in the range 0.26-0.56 km³. That makes this episode also the largest magmatic unrest ever geophysically monitored in Antarctica. Simone Cesca continues: "Our study represents a new successful investigation of a seismo-volcanic unrest at a remote location on Earth, where the combined application of seismology, geodesy and remote sensing techniques are used to understand earthquake processes and magma transport in poorly instrumented areas. This is one of the few cases where we can use geophysical tools to observe intrusion of magma from the upper mantle or crust-mantle boundary into the shallow crust -- a rapid transfer of magma from the mantle to almost the surface that takes only a few days." The above story is based on <a href="https://www.gfz-potsdam.de/en/press-public-relations/news/details/ein-schwarm-von-85000-erdbeben-am-antarktischen-unterwasservulkan-orca" rel="nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px !important; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">Materials</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline !important; float: none; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;"> provided by <a href="https://www.gfz-potsdam.de/en/" rel="nofollow" style="-webkit-text-stroke-width: 0px; background-color: white; border-radius: 0px !important; box-sizing: border-box; color: #004276; font-size: 14px; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px;" target="_blank">GFZ GeoForschungsZentrum Potsdam, Helmholtz Centre</a><span style="-webkit-text-stroke-width: 0px; background-color: white; color: #333333; display: inline !important; float: none; font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 14px; font-style: normal; font-variant-caps: normal; font-variant-ligatures: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-decoration-color: initial; text-decoration-style: initial; text-decoration-thickness: initial; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px;">.

Record-Breaking Earthquake Swarm Hits Antarctica as Sleeping Volcano Awakens

A long-dormant underwater volcano near Antarctica has woken up, triggering a swarm of 85,000 earthquakes. Volcanoes can be found even off ...

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