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#geophysics

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Nicole Sharp

Martian Streaks Are Dry

Dark lines appearing on Martian slopes have triggered theories of flowing water or brine on the planet’s surface. But a new study suggests that these features are, instead, dry. To explore these streaks, the team assembled a global database of sightings and correlated their map with other known quantities, like temperature, wind speed, and rock slides. By connecting the data across thousands of streaks, they could build statistics about what variables correlated with the streaks’ appearance.

What they found was that streaks didn’t appear in places connected to liquid water or even frost. Instead, the streaks appeared in spots with high wind speeds and heavy dust accumulation. The team included that, rather than being moist areas, the streaks are dry and form when dust slides down the slope, perhaps triggered by high winds or passing dust devils.

Although showing that the streaks aren’t associated with water may seem disappointing, it may mean that NASA will be able to explore them sooner. Right now, NASA avoids sending rovers anywhere near water, out of concern that Earth microbes still on the rover could contaminate the Martian environment. (Image credit: NASA; research credit: V. Bickel and A. Valantinas; via Gizmodo)

#fluidDynamics#geophysics#Mars
Nicole Sharp

Io’s Missing Magma Ocean

In the late 1970s, scientists conjectured that Io was likely a volcanic world, heated by tidal forces from Jupiter that squeeze it along its elliptical orbit. Only months later, images from Voyager 1’s flyby confirmed the moon’s volcanism. Magnetometer data from Galileo’s later flyby suggested that tidal heating had created a shallow magma ocean that powered the moon’s volcanic activity. But newly analyzed data from Juno’s flyby shows that Io doesn’t have a magma ocean after all.

The new flyby used radio transmission data to measure any little wobbles that Io caused by tugging Juno off its expected course. The team expected a magma ocean to cause plenty of distortions for the spacecraft, but the effect was much slighter than expected. Their conclusion? Io has no magma ocean lurking under its crust. The results don’t preclude a deeper magma ocean, but at what point do you distinguish a magma ocean from a body’s liquid core?

Instead, scientists are now exploring the possibility that Io’s magma shoots up from much smaller pockets of magma rather than one enormous, shared source. (Image credit: NASA/JPL/USGS; research credit: R. Park et al.; see also Quanta)

#fluidDynamics#geophysics#Io
Nicole Sharp

Ponding on the Ice Shelf

Glaciers flow together and march out to sea along the Amery Ice Shelf in this satellite image of Antarctica. Three glaciers — flowing from the top, left, and bottom of the image — meet just to the right of center and pass from the continental bedrock onto the ice-covered ocean. The ice shelf is recognizable by its plethora of meltwater ponds, which appear as bright blue areas. Each austral summer, meltwater gathers in low-lying regions on the ice, potentially destabilizing the ice shelf through fracture and drainage. This region near the ice shelf’s grounding line is particularly prone to ponding. Regions further afield (right, beyond the image) are colder and drier, often allowing meltwater to refreeze. (Image credit: W. Liang; via NASA Earth Observatory)

#fluidDynamics#geophysics#glacier
Nicole Sharp

Non-Newtonian Effects in Magma Flows

As magma approaches the surface, it forces its way through new and existing fractures in the crust, forming dikes. When a volcano finally erupts, the magma’s viscosity is a major factor in just how explosive and dangerous the eruption will be, but a new study shows that what we see from the surface is a poor predictor of how magma actually flows within the dike.

Researchers built their own artificial dike using a clear elastic gelatin, which they injected water and shear-thinning magma-mimics into. By tracking particles in the liquids, they could observe how each liquid followed on its way to the surface. All of the liquids formed similar-looking dikes at a similar speed, but within the dike, the liquids flowed very differently. Water cut a central jet through the gelatin, then showed areas of recirculation along the outer edges. In contrast, the shear-thinning liquids — which are likely more representative of actual magma — showed no recirculation. Instead, they flowed through the dike in a smooth, fan-like shape.

The team cautions that surface-level observations of developing magma dikes provide little information on the flow going on underneath. Instead, their results suggest that volcanologists modeling magma underground should take care to include the magma’s shear-thinning to properly capture the flow. (Image credit: T. Grypachevska; research credit: J. Kavanagh et al.; via Eos)

#fluidDynamics#geophysics#magma
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Ele Willoughby, PhD

Happy birthday to Danish #seismologist Inge Lehmann (1888 – 1993) who demonstrated that the Earth’s core is not a single molten sphere, but contained an inner solid core, in ‘36. She was a pioneer #womanInScience, a brilliant seismologist & lived to be 105.⁠
⁠
As she first postulated, the #earth has roughly 3 equal concentric sections: mantle, liquid outer core & solid inner core. The crust, on which we live is merely 🧵1/n

#printmaking#sciArt#geophysics
💧🌏 Greg Cocks

REGIS II - The Hydrogeological Model [Nederlands]
--
dinoloket.nl/en/regis-ii-the-h <-- shared project/data overview 1
--
dinoloket.nl/en/subsurface-mod <-- shared web mapping site
--
basisregistratieondergrond.nl/ <-- shared project/data overview 2
--
#GIS #spatial #mapping #geology #hydrogeology #Nederland #Holland #Dutch #wells #boreholes #data #core #lithology #REGISII #hydrogeological #model #spatialanalysis #water #hydrology #aquifer #aquitard #opendata #digital #sedimentology #hydrologic #pumping #tests #hydraulic #conductivity #transmissivity #geophysics

Mainz University

Energy from the depths of the Earth: Collaborative research project studies temperature-induced change of rocks in geothermal reservoirs / Geothermal energy as a major driver in the energy revolution / German Federal Ministry for Economic Affairs and Energy provides funding for research on small-scale processes in rocks for deep #GeothermalReservoirs 👉 press.uni-mainz.de/energy-from

#GeothermalEnergy#EnergyRevolution#geophysics
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okanogen VerminEnemyFromWithin

Let's talk about "#AI", #LLM, and #MachineLearning, which I don't put in quotes.
First, I am not anti-science, I am anti-JUNKscience and MARKETING, and there is a difference.
Why can I discuss a field I'm not in with some knowledge? I spent over 30 years in #geophysics, #SignalProcessing, and in #geology and #hydrology and #hydrogeology modelling. People doing this kind of work (along with #meteorology and #Climatology) are the progenitors of the current science. 1/

Nicole Sharp

On the Mechanics of Wet Sand

Sand is a critical component of many built environments. As most of us learn (via sand castle), adding just the right amount of water allows sand to be quite strong. But with too little water — or too much — sand is prone to collapse. For those of us outside the construction industry, we’re most likely to run into this problem on the beach while digging holes in the sand. In this Practical Engineering video, Grady explains the forces that stabilize and destabilize piled sand and where the dangers of excavation lie. (Video and image credit: Practical Engineering)

#civilEngineering#fluidDynamics#geophysics
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Skeptical Science

Our own @BaerbelW traveled to Vienna for this year's #EGU25 General Assembly of the @EuroGeosciences

Baerbel herself did a couple of presentations in Vienna:

* Examples of Skeptical Science successfully collaborating with other organizations so as to better reach shared goals, get more gain for less effort. With so much reward, we're eager to do more.

* How Skeptical Science translates our content into 29 different languages, the challenges of maintaining a polyglot presence. You may be able to help!

Baerbel also kept a daily journal. It's loaded with links to scads of intriguing information presented at the assembly by many researchers, with teasers and organized for easy access.

Post facto virtual attendance , distilled and at our fingertips. :-)

#geoscience
#geophysics
#ScienceCommunication

skepticalscience.com/egu25-per

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