#seismicwaves — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #seismicwaves, aggregated by home.social.
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Glacial Collapse Led to Seismic Event in Nepal
#Flash flood #GlacialCollapse #GlacialLakeOutburst #Mudslides #Nepal #SeismicEvent #SeismicWaves #Tibet
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Convection Inside the Mantle
Most of what we know about Earth’s interior comes from observing how seismic waves–mostly from earthquakes–bounce around. As our observations have gotten better–more seisometers, better imaging techniques–scientists have identified two large anomalies sitting near the bottom of the mantle. Known as large low-velocity provinces, or LLVPs, these zones take up continent-sized areas beneath parts of Africa and the Pacific.
Seismic waves show lower speeds in large, continent-sized zones that sit beneath Africa and the Pacific. These large low-velocity provinces (LLVPs) are outlined in red.The LLVPs are hot, which would normally make them buoyant, but their stationary nature suggests they are made up of extremely dense material. Narrow plumes of hot material make their way up from the LLVPs to form volcanic hotspots like those that made the Hawaiian and Galapagos Islands. Balancing that upward convection is the downward convection of former tectonic material carried into the mantle at subduction zones.
What the LLVPs are made of remains an active research question. One suggestion is that they contain remnants of Theia, the planet thought to have impacted the proto-Earth to form our Moon. (Image credits: E. Garnero and C. Richardson; see also Physics Today)
Illustration showing convection in the Earth’s inner mantle. Former tectonic material subducts downward in dark blue zones. The large low-velocity provinces (LLVPs) are shown in orange. Hot-spot volcanic activity is seen at the surface (black triangles) above narrow plumes that lift material from the LLVPs toward the surface. #buoyancy #convection #fluidDynamics #geophysics #mantleConvection #physics #science #seismicWaves -
Slipping Ice Streams
The Northeast Greenland Ice Stream provides about 12% of the island’s annual ice discharge, and so far, models cannot accurately capture just how quickly the ice moves. Researchers deployed a fiber-optic cable into a borehole and set explosive charges on the ice to capture images of its interior through seismology. But in the process, they measured seismic events that didn’t correspond to the team’s charges.
Instead, the researchers identified the signals as small, cascading icequakes that were undetectable from the surface. The quakes were signs of ice locally sticking and slipping — a failure mode that current models don’t capture. Moreover, the team was able to isolate each event to distinct layers of the ice, all of which corresponded to ice strata affected by volcanic ash (note the dark streak in the ice core image above). Whenever a volcanic eruption spread ash on the ice, it created a weaker layer. Even after hundreds more meters of ice have formed atop these weaker layers, the ice still breaks first in those layers, which may account for the ice stream’s higher-than-predicted flow. (Image credit: L. Warzecha/LWimages; research credit: A. Fichtner et al.; via Eos)
#fluidDynamics #geology #geophysics #glacier #glaciology #ice #iceFormation #physics #science #seismicWaves #seismology
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A Seismic Warning for the Tongan Eruption
In mid-January 2022, the Hunga Tonga-Hunga Ha’apai (HTHH) volcano had one of the most massive eruptions ever recorded, destroying an island, generating a tsunami, and blanketing Tonga in ash. Volcanologists are accustomed to monitoring nearby seismic equipment for signs of an imminent eruption, but researchers found that the HTHH eruption generated a surface-level seismic wave picked up by detectors 750 kilometers away about 15 minutes before the eruption began. They propose that the seismic wave occurred when the oceanic crust beneath the caldera fractured. That fracture could have allowed seawater and magma to mix above the volcano’s subsurface magma chamber, creating the explosive trigger for the eruption. Their finding suggests that real-time monitoring for these distant signals could provide valuable early warning of future eruptions. (Image credit: NASA Earth Observatory; research credit: T. Horiuchi et al.; via Gizmodo and AGU News)
#eruption #fluidDynamics #physics #science #seismicWaves #seismology #volcano
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What caused the Mysterious Seismic Waves Recorded in September 2023
In September 2023, uniform single frequency seismic waves were recorded at centres across the globe which lasted for nine days............
#ClimateChange #Dicksonfjord #Eartquake #Fjord #Globalwarmimg #Greenland #Polarice #Seismicwaves
SCIEU Team -
Rapid Response Seafloor Seismology [USGS]
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https://www.usgs.gov/news/featured-story/rapid-response-seafloor-seismology <-- shared technical article
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#GIS #spatial #mapping #geology #earthquakes #monitoring #remotesensing #geohazards #marine #massmovement #geology #engineeringgeology #tsunami #volcano #risk #hazard #forecasting #seafloor #seismology #hazardmaps #models #modeling #mitigation #seismograph #seismicwaves #instrumentation #underwater #remote #tectonics
@USGS -
🌋 #Earthquakes and #volcanic eruptions reminds us that events on the surface are connected to processes deep within the Earth. @arwendeuss at @UniUtrecht is scanning #seismicwaves to better understand their journey inside the Earth 🌍
More👉 http://bit.ly/3xrRLTK
@CORDIS_EU🐦🔗: https://n.respublicae.eu/ERC_Research/status/1626869174701264896
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Seismic sound waves crossing the deep ocean could be a new thermometer - Enlarge / A seismometer on the atoll of Diego Garcia (left) can calculate ocean temperature with ea... - https://arstechnica.com/?p=1709779 #earthquakemonitoring #oceantemperatures #seismicwaves #science #sumatra