Create accountLogin

Recent searches

No recent searches

Search options

Only available when logged in.
med-mastodon.com is one of the many independent Mastodon servers you can use to participate in the fediverse.
Medical community on Mastodon

Administered by:

Server stats:

411
active users

med-mastodon.com: AboutProfiles directoryPrivacy policy

Mastodon: AboutGet the appKeyboard shortcutsView source codev4.3.7

#geophysics

2 posts2 participants0 posts today
Public
Nicole Sharp

Arctic Melt

Temperatures in the Arctic are rising faster than elsewhere, triggering more and more melting. Photographer Scott Portelli captured a melting ice shelf protruding into the ocean in this aerial image. Across the top of the frozen landscape, streams and rivers cut through the ice, leading to waterfalls that flood the nearby ocean with freshwater. This meltwater will do more than raise ocean levels; it changes temperature and salinity in these regions, disrupting the convection that keeps our planet healthy. (Image credit: S. Portelli/OPOTY; via Colossal)

A melting ice shelf in the Arctic showers freshwater into the ocean.
#climateChange#convection#fluidDynamics
Public
bse

9-month Geo position at Skidmore: earth materials, geophysical methods, intro. "Expertise in any of the following areas is desirable: #petrology, #mineralogy, #geophysics, tectonics, Earth history, and related fields." ⚒️🧪 #geology

eodq.fa.us6.oraclecloud.com/hc

Skidmore CareersVisiting Assistant Professor, GeosciencesThe Department of Geosciences at Skidmore College invites applications for a full-time, 9-month appointment as Visiting Assistant Professor to begin fall 2025. We seek a broadly trained geologist with strong teaching capabilities in solid Earth processes and Deep Time to offer both introductory and advanced classes. During the 2025-2026 academic year, the successful candidate will be expected to teach an intermediate-level laboratory course in Earth Materials, an intermediate-level course in geophysical methods, and two sections of an introductory course with lab. Expertise in any of the following areas is desirable: petrology, mineralogy, geophysics, tectonics, Earth history, and related fields. Women and minority candidates are encouraged to apply. A Ph.D. in an appropriate Earth science discipline or closely related field is required by the time of appointment, and prior teaching experience is desirable. Candidates should submit a letter of interest, CV, Statement of Teaching (i...
Public
Nicole Sharp

Reclaiming the Land

Lava floods human-made infrastructure on Iceland’s Reykjanes peninsula in this aerial image from photographer Ael Kermarec. Protecting roads and buildings from lava flows is a formidable challenge, but it’s one that researchers are tackling. But the larger and faster the lava flow, the harder infrastructure is to protect. Sometimes our best efforts are simply overwhelmed by nature’s power. (Image credit: A. Kermarec/WNPA; via Colossal)

Aerial view of lava overflowing a road and the surrounding landscape in Iceland.
#fluidDynamics#fluidsAsArt#geophysics
Public
Nicole Sharp

Thawing Permafrost Primes Slumps

As permafrost thaws on Arctic hillsides and shorelines, the land often deforms in a unique fashion, known as a slump. Formally known as mega retrogressive thaw slumps, these areas superficially resemble a landslide. They’re also prone to repeat performances: as many as 90% of Canada’s Arctic slumps recur in the same place as previous slumps. Researchers used ground-penetrating radar and other tools to study the underground structure at slumps and found that several factors contribute to this repetitive cycle.

Seawater soaking into the foot of a hilly shore can destabilize the permafrost, creating a slump. That changes the nearby ground cover, exposing more permafrost to warming; their measurements showed this warming could extend tens of meters underground, priming the area for future slumps. Similarly, the mudslides and narrow ravines that form on an active slump also shift away ground cover and warm the underlying permafrost. Together, these factors suggest that once a slump forms, more slumps will occur as the underlying permafrost warms. (Image credit: M. Krautblatter; research credit: M. Krautblatter et al.; via Eos)

Aerial view of a slump on Herschel Island in the Canadian Yukon.
#erosion#fluidDynamics#geophysics
Public *
💧🌏 Greg Cocks

Kinematic Evolution Of A Large Paraglacial Landslide In The Barry Arm Fjord Of Alaska
--
doi.org/10.1029/2023JF007119 <-- shared paper
--
doi.org/10.5066/P9EUCGJQ <-- shared technical article
--
sciencebase.gov/catalogMaps/ma <-- shared web mapping service
--
#GIS #spatial #mapping #massmovement #landslide #engineeringgeology #remotesensing #sitespecific #LiDAR #iFSAR #paraglacial #kinematics #mapping #monitoring #spatialanalysis #spatiotemporal #fedscience #risk #hazard #glacier #retreat #climatechange #Alaska #BarryArm #fjord #hazardassessment #tsunami #wave #BarryGlacier #change #sensors #fieldwork #surveillance #melting #permafrost #Whittier #geophysics #geology #Alaska #geomorphometry #deglaciating
@USGS

Public
Nicole Sharp

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)

A researcher holds a polished ice core containing a thin layer of ash.
#fluidDynamics#geology#geophysics
Public
Nicole Sharp

Salt Affects Particle Spreading

Microplastics are proliferating in our oceans (and everywhere else). This video takes a look at how salt and salinity gradients could affect the way plastics move. The researchers begin with a liquid bath sandwiched between a bed of magnets and electrodes. Using Lorentz forcing, they create an essentially 2D flow field that is ordered or chaotic, depending on the magnets’ configuration. Although it’s driven very differently, the flow field resembles the way the upper layer of the ocean moves and mixes.

The researchers then introduce colloids (particles that act as an analog for microplastics) and a bit of salt. Depending on the salinity gradient in the bath, the colloids can be attracted to one another or repelled. As the team shows, the resulting spread of colloids depends strongly on these salinity conditions, suggesting that microplastics, too, could see stronger dispersion or trapping depending on salinity changes. (Video and image credit: M. Alipour et al.)

#2024gofm#electrohydrodynamics#flowVisualization
Public
Nicole Sharp

Flooding the Mediterranean

Nearly 6 million years ago, the Mediterranean was cut off from the ocean and evaporated faster than rivers could replenish it. This created a salty desert that persisted until about 5.3 million years ago. One hypothesis — the Zanclean megaflood — suggests that the Mediterranean refilled rapidly through an erosion channel near the Strait of Gilbraltar. A new study bolsters the concept by identifying geological features near Sicily consistent with the megaflood.

The team point to a grouping of over 300 ridges near the Sicily Sill, once a land bridge dividing the eastern and western Mediterranean and now underwater. The ridges are layered in debris but aren’t streamlined, suggesting they were rapidly deposited by turbulent waters, and date to the period of the proposed flooding. For more on the Zanclean Flood, check out this older post. (Image credit: R. Klavins; research credit: A. Micallif et al.; via Gizmodo)

The blue dome of a church on Santorini, overlooking the Mediterranean.
#erosion#flooding#fluidDynamics
Public *
💧🌏 Greg Cocks

Grfin Tools—User Guide And Methods For Modeling Landslide Runout And Debris-Flow Growth And Inundation
--
pubs.usgs.gov/publication/tm14 <-- shared USGS publication
--
code.usgs.gov/grfintools/grfin <-- shared USGS software release
--
H/T Jonathan Perkins USGS
[ another open source resource for everyone from the USGS ~smile~ ]
#GIS #spatial #mapping #opensource #openlibrary #Grfin #software #package #regional #debrisflow #engineeringgeology #geology #inundation #spatialanalysis #spatiotemporal #geophysics #geophysical #massmovement #landslide #lahar #volcano #rock #avalanche #model #modeling #statistical #geostatistics #water #hydrology #downstream #elevation #remotesensing #DEM #flow #runout #risk #hazard #tools #slope #erosion #drainage #network #channel #channelisation #userguide
@USGS

screen shot - grfintools software repository home page (https://code.usgs.gov/grfintools/grfintools)
report figure 2 - Schematic flowchart illustrating common pathways for using Grfin Tools with examples identified in orange boxes
report figure 1 - Perspective view of topography illustrating the potential locations for three types of mass movements that can be derived from a Grfin Tools analysis.
USGS report cover page - Grfin Tools—User Guide And Methods For Modeling Landslide Runout And Debris-Flow Growth And Inundation
Public
Project Gutenberg

Danish seismologist and geophysicist Inge Lehmann died #OTD in 1993.

She is best known for her discovery in 1936 of the solid inner core that exists within the molten outer core of the Earth. The seismic discontinuity in the speed of seismic waves at depths between 190 and 250 km is named the Lehmann discontinuity after her. Lehmann is considered to be a pioneer among women and scientists in seismology research.

en.wikipedia.org/wiki/Inge_Leh

Lehmann in 1932. Image courtesy The Royal Library, National Libary of Denmark and University of Copenhagen University Library, under a Creative Commons License. Even Neuhaus (6.2.1863-20.4.1946) - http://www5.kb.dk/images/billed/2010/okt/billeder/object11164/da/ The photograph is sepia-toned and features Lehmann with a composed expression, wearing a modest dark jacket over a white blouse. Her hair is neatly pulled back, and she has a serious, determined gaze. The signature "Marthæus 1932" is visible in the lower right corner.
#seismology#geophysics#womeninStem
Public
Ralph-Uwe Börner

✅ My PR has been merged into the IAGA International Geomagnetic Reference Field (IGRF) ppigrf repository. The changes provide users with greater control over the spherical harmonics expansion by allowing them to specify the minimum and maximum degree of the expansion.

The animation shows the multipole contributions to Earth's global magnetic field displayed as field magnitude. This illustrates the complexity of the geomagnetic field.

github.com/IAGA-VMOD/ppigrf/pu

GIF
#geophysics#python#igrf
Public
Miss Gayle

'Impossible' Earthquake Challenges Everything We Knew About Earth's Interior, StudyFinds

studyfinds.org/impossible-eart

Scientists have solved the mystery of how earthquakes can occur 420 miles deep inside Earth, where extreme pressure and heat should make rock flow rather than break. The key is a mineral called olivine that transforms under pressure, creating conditions for earthquakes at impossible depths.

‘Impossible’ earthquake challenges everything we knew about Earth’s interior By StudyFinds Staff, Reviewed by Steve Fink Research led by Hao Zhang, University of Southern California Jan 28, 2025 Overview of the study region. (a) Map illustrating the focal mechanism of the mainshock (blue focal mechanism plot), the distribution of seismicity in the Izu–Bonin subduction zone (from 2000 to 2023, dots color‐coded by depth), and Hi‐net stations (triangles). The static time correction applied to each station used in the back-projection analysis is represented by color. The black line indicates the cross section A–A′. Toothed lines indicate subduction zones; dashed lines indicate convergent boundaries. (b) Cross section including earthquake locations within 50 km of profile A–A′, with a side‐view projection of the focal mechanism. Most earthquakes are magnitude 4–5, so we do not differentiate magnitudes by marker size. (Credit: The Seismic Record)
#Earthquake#Seismology#GeoPhysics
ExploreLive feeds
About