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Publication date: Available online 8 December 2025

Source: Advances in Space Research

Author(s): Alberto Regadío, Juan José Blanco, J. Ignacio García Tejedor, Carlo Luis Guerrero, Du Toit Strauss

Publication date: Available online 8 December 2025

Source: Advances in Space Research

Author(s): Bhanu Kumar, Anjali Rawat, Aaron J. Rosengren, Shane D. Ross

Publication date: Available online 6 December 2025

Source: Advances in Space Research

Author(s): Jiahao Qin, Hongxia Wang, Xudong Gao, Qian Wang, Xi Chen

SummaryThis study introduces a novel inversion approach to resolve the layered anisotropic structure of the Earth’s crust and upper mantle using harmonic patterns observed in Ps receiver functions (RFs). Designed for dense seismic networks, our method effectively captures the complexity and deformation of subsurface structures by leveraging the decomposition of RF patterns into five harmonic functions representing distinct terms in a harmonic regression model. Our approach combines residual weighting at individual and coherency weighting between stations to reduce noise and enhance structural signal, followed by a direct inversion of harmonic patterns alongside a multi-phase stack. This process is optimized using a Markov chain Monte Carlo framework to iteratively explore model space and define posterior distributions, which yields robust model parameter estimates with quantified uncertainties. We validated our approach with both synthetic models and real data from the dense SEISConn seismic transect in Northern Connecticut. The synthetic test highlighted the reliability of coherency weighting in reducing noise. Real data analysis revealed anisotropic and structural features consistent with geological expectations and previous studies, including shallow anisotropy in western Connecticut, a shallowing Moho towards the Hartford basin, and indications for a west-dipping layer beneath the Moho in the lithospheric mantle. Our approach offers a promising tool for revealing the details of anisotropic features beneath dense seismic profiles, facilitating insights into tectonic history and lithospheric deformation.

SummaryLarge-scale geodetic monitoring of volcanic earthquakes is essential for understanding the physical mechanisms governing volcanic activity and magma migration. Recently, a significant earthquake swarm occurred around the Scotia plate. Geodetic data of 14 permanent GNSS stations on the Antarctic Peninsula, King George Island, the South Sandwich Islands, and South America were collected and analyzed, to monitor the crustal deformation of King George Island, the expansion of Bransfield Strait, the drift of Scotia plate, and sea level anomalies. Tidal data from four permanent tide stations were analyzed to monitor sea level anomalies. Results showed that after earthquakes the King George Island’s movement speed increased tenfold and its direction altered by 90 degrees. Land surface fluctuations in southeast King George Island were observed a year before the earthquakes, followed by continuous uplift. A combinatorial model including a point pressure source and expanding dike fit well with new geodetic monitoring data, revealing the impact of volcanic activity on this region. Geodetic monitoring and modeling quantitatively depicted the pre-seismic, co-seismic, and post-seismic phases of geological changes, providing new evidence and insights into the complex geological structures.

SummaryA 220 km long active seismic profile crossing the Saronic and Corinth Gulfs was performed using 35 4C Ocean Bottom Seismographs (OBS) and 4 3C stand-alone land stations. We recorded shots fired along line at every 120 m from a 48-l airgun array of 51 bar-m power. The velocity model was developed by first break tomographic inversion, followed by kinematic and dynamic ray tracing. The final velocity model was used to prestack depth migrate the Common Receiver Gathers. Moho depth below the central Corinth Basin is located at 32 km, thinning to 22 km below the Lechaio Gulf, at the transition to the Saronic Basin. In the Saronic domain Moho is found at 19 to 21 km depth, whereas below we identified a low velocity upper mantle of Vp 7.5 to 7.6 km/s, extending to 34 km depth. This is a low velocity asthenosphere wedge that intruded from the Cyclades region below the Saronic Gulf, driving the volcanic activity. It does not extend in the Corinth Rift domain to the west, where Pn is 8.0 km/s. Two major extensional detachments were mapped along the profile: one to the NW in the central Corinth Gulf, east of Galaxidi, corresponding to the onshore Itea-Amfissa Detachment, having a throw of more than 2000 m; the other to the SE, west of Agios Georgios Island, separates the Cycladic Metamorphic Core Complex from the non-metamorphic internal nappes of the Hellenides. Thrusting to the NW observed in the SE Saronic Basin has doubled the thickness of the high velocity limestones. At 20 km SE of Agios Georgios Island a major dextral strike slip fault was mapped. Normal faults with more than 1 km throw are observed around the Isthmus of Corinth trending E-W and WNW-ESE. Maximum thickness of 2000 m of Middle Miocene-Quaternary sediments (Vp 2.1–2.8 km/s and 3.4 km/s) is observed in the Corinth Gulf and minimum of 200 m of Quaternary sediments above the western Cyclades. Beneath the volcanoes of Aegina, Methana, Paphsanias, and Sousaki the crust has a lateral Vp velocity increase of nearly 3 per cent, whereas depth migrated data show high reflectivity, indicating magma intrusions through the crust. Mesozoic limestones with Vp 5.2 to 5.8 km/s and 1800 to 2000 m thickness occur along the profile, corresponding probably to the Tripolis external carbonate platform, whereas limestones and flysch with Vp 4.3 to 5.5 km/s are overlying, probably corresponding to pelagic sequences like the Pindos nappe. The Saronic domain is characterized by arc-parallel NW-SE structures, hosting the volcanic arc, and is tectonically controlled by magma uplift and thermally triggered deformation. The Corinth domain is affected by E-W transverse-oblique structures of a rapidly developing continental rift, and deformation driven by fracturing of a brittle crust of the Central Hellenic Shear Zone.

Much of the heavy rains that hit the Philippines during the Amihan northeast monsoon season between November and March are triggered by "shear lines": kilometers-long bands of converging warm and cold air that are constantly shifting and difficult to spot even via satellite.

The climate is changing and nowhere is it changing faster than at Earth's poles. Researchers at Penn State have painted a comprehensive picture of the chemical processes taking place in the Arctic and found that there are multiple, separate interactions impacting the atmosphere.

In April 2025, the Main Marmara Fault below the Sea of Marmara in northwestern Türkiye experienced its largest earthquake in over 60 years. In a study published in Science, a team of researchers led by Prof. Dr. Patricia Martínez-Garzón from the GFZ Helmholtz Center for Geosciences in Potsdam, Germany, analyzes nearly two decades of seismic data framing the 2025 April magnitude M 6.2 earthquake.

Droughts are lasting longer in Australia, particularly in some of our most populated regions, UNSW scientists have shown.

In Alaska, winter is more than a season—it is survival. For Indigenous communities in Aniak, St. Mary’s, and Elim, snow and frozen rivers guide travel, hunting, and fishing. But those conditions are becoming less reliable in the Arctic, the fastest-warming region on Earth.

“The spring and the fall seasons are crunching in on the time frame where there’s enough snow and safe conditions to be able to move around,” said Helen Cold, a subsistence resource specialist with the Alaska Department of Fish and Game.

Indigenous communities “know their river better than anyone else in the world.”

With the Arctic Rivers Project, scientists and community leaders are racing to track changes in Alaska’s winters and plan for the future. By combining Indigenous Knowledges with high-resolution climate models, a team is working to build a collection of “storylines” to capture winter shifts and serve as tools for adaptation.

“There’s been a big movement in climate science to use narrative approaches to describe impacts,” said University of Colorado Boulder hydrologist Keith Musselman, who will present the research with his team on 15 December at AGU’s Annual Meeting 2025 in New Orleans. After all, Indigenous communities “know their river better than anyone else in the world.”

Voices from the River

Musselman and his colead, Andrew Newman, a hydrometeorologist at the National Science Foundation’s National Center for Atmospheric Research, leaned on local leadership by creating an Indigenous Advisory Council of 10 regional representatives. The council shaped research questions and ensured Indigenous Knowledges guided methods, data, and interpretation throughout the project.

To understand initial concerns, the research team convened the 2022 Arctic Rivers Summit to hear directly from community members. During the summit, council members emphasized the importance of inclusive planning to address climate change in ways that safeguard both people and ecosystems. In conjunction with the summit, interviews and workshops captured observations of shorter winters, thinner snowpack, midwinter thaws, and hazardous river ice. One respected elder and 15-time Iditarod racer shared that in his lifetime, he has witnessed more intense snowfall events and reduced snow persistence. Some communities also voiced concerns about more frequent coastal storms and shifts in wildfire patterns driven by lightning during dry periods.

Indigenous Knowledge holders shared their knowledge during a participatory mapping workshop in Kotlik, Alaska, as part of the Arctic Rivers Project. Credit: Nicole M. Herman-Mercer, USGS

Such shifts have major consequences, including reduced food security for Indigenous people who rely heavily on the land. Michael Williams, an Aniak tribal advocate and Indigenous Advisory Council member, said these climatic changes “make our hunting practices very dangerous.” Over the past 20 to 40 years, he has observed extreme temperatures in the area and a nearly 50% reduction in ice thickness on nearby rivers—changes that make traveling and hunting mammals, migratory birds, and fish a serious challenge.

“It has changed everything here,” Williams said. “It’s affecting our ways of life.”

Bridging River Wisdom and Climate Data

Researchers compared community observations with data from historical records, satellite measurements, and U.S. Geological Survey sensors to recreate past conditions and generate six climate scenarios for Alaska’s winters from 2035 to 2065. Beyond standard climate indicators like air temperature, the chain of models simulated hydroclimatic patterns such as streamflow, snowmelt timing, river ice dynamics, and fish population conditions.

Records corroborated what communities had observed for years, and the models indicated even harsher changes could be ahead, although northern regions could see increased snowpack as winter precipitation rises. Translating these results into usable guidance requires careful planning. Communities were both concerned and curious when shown initial results, asking to compare conditions across regions to understand what their neighbors were experiencing.

“If we don’t include [Indigenous voices], then we’re dead. We’re good as dead.”

The initial phase of the project, which involved gathering and analyzing information, ended in 2024. But to support effective, accessible communication, the team will continue codeveloping “narratives of change” that weave together datasets, Indigenous Knowledges, and lived experience. They’re also exploring how tools like maps and Facebook channels can help share science with affected communities, with the goal of supporting intuitive, locally led adaptation as climate change reshapes life in Alaska.

Past adaptation strategies have often fallen short in including Native realities, said Cold, who was not involved in the research. She thinks the Arctic Rivers Project’s approach is a step in the right direction toward more inclusive climate planning.

Community leaders echo that sentiment and emphasize the urgency of such efforts. “Mitigation planning has to be ongoing in our communities for the survival of our people,” Williams said. “If we don’t include [Indigenous voices], then we’re dead. We’re good as dead.”

—Cassidy Beach, Science Writer

Citation: Beach, C. (2025), Changing winters leave Indigenous Alaskans on thin ice, Eos, 106, https://doi.org/10.1029/2025EO250466. Published on 12 December 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Researchers at the Institute for Meteorology at Leipzig University have, for the first time, determined the climatic impact of contrails that form within natural cirrus clouds. Contrails account for the largest share of aviation's climate impact beyond carbon dioxide emissions.

Mangroves are a critical component of many coastal ecosystems, serving as havens for biodiversity, carbon sinks, barriers against storm-driven winds and waves, and bulwarks against erosion. But increasing levels of erosion from sea level rise, lack of freezing, higher-intensity storms, and land development are threatening these vulnerable, valuable ecosystems. The problem is especially poignant in Louisiana, which is losing land to the sea faster than any other state.

New research has found that sand made from recycled glass could help restore coastal mangrove ecosystems near New Orleans, serving as a growing medium for new mangroves and replenishing sediment that has washed away.

“New Orleans is a city of festivals,” said Kathryn Fronabarger, an ecologist and environmental compliance specialist at Tulane University in New Orleans and a researcher on the project. “There is a ton of glass waste in the city—glass beads, glass bottles.”

“At one point, a glass bottle was just thrown on the ground, trashed, discarded, put in a landfill,” Fronabarger said. “Now we’re seeing it used as a substrate in multiple states across the United States to build back parishes, build back communities.”

“When we hold those places together,” she added, “we preserve irreplaceable cultures and identities.”

Reuse, Recycle, Restore

Louisiana has the fastest rate of land loss in the United States, losing 28 square kilometers of coastal wetlands per year. That’s the same as losing an American football field’s worth of land every 100 minutes. Climate change is intensifying storms, and the barrier islands that had softened the storms’ impacts have disappeared under rising seas. This loss of protection has sped up coastal erosion.

“It’s absolutely a positive feedback loop, and if anything, it’s an exponential one,” Fronabarger said. The more land that erodes, the more that is exposed to future erosion. And while mangrove roots are great at trapping and retaining sediment, there still has to be sediment in which they can grow.

“Sediment is running out. Eventually, the solution collapses in on of itself.”

Although local and regional efforts have sought to create artificial reefs and barrier islands to prevent coastal erosion, no statewide programs have truly been effective at holding back the tides.

What’s more, the most common method of restoring eroded coastline, dredging riverbeds and transporting that sediment to the coast, damages river ecosystems, may not be suitable for growing mangroves, and is not sustainable in the long run.

“Sediment is running out,” Fronabarger said. “Eventually, the solution collapses in on of itself.”

Seeking an alternate approach to restoring coastal mangrove ecosystems, Fronabarger’s team looked into whether glass that had been ground down to its original form—that is, sand—could sustain mangrove growth.

The team collected 15–20 black mangrove propagules each from 15 parent plants in Grand Isle in 2023. They transported the propagules to a greenhouse and planted them in three different substrates: sediment dredged from the Mississippi River, recycled glass sand, and a 50:50 blend of both. Some plants were inoculated against fungal growth while others were not.

“I was never so happy to see a null in my life.”

The results surprised the researchers. They found that mangroves grown in glass sand developed the same amount of biomass as those grown in both the dredged sediment and the substrate blend. Inoculating the mangroves increased the plants’ survival rate from 70% to 93% but didn’t change the total biomass.

“I was never so happy to see a null in my life,” Fronabarger joked.

Another surprise was that the glass-grown mangroves had different a root structure than those grown in sediment or blended substrate despite the growing mediums having similar grain sizes. The structural roots of glass-grown mangroves were 26% thicker than those of sediment-grown mangroves, but the fine roots were 55% shorter. That could change the mangroves’ long-term stability in a turbulent coastal environment, the researchers said.

The team published these results in Restoration Ecology in July and will present its findings on 15 December at AGU’s Annual Meeting 2025 in New Orleans.

This illustration depicts how a black mangrove tree might grow in either recycled glass sand or dredged river sediment. In their experiments, the researchers grew mangrove propagules in buckets filled with different substrates and measured the plants’ root properties (extraradial and intraradial) and how inoculating against fungi (mycelium hyphae) affected growth. Credit: AC Frye From Trash to Treasure

“Recycled glass sand is increasingly being identified as a potential cost-effective source of local sediment for these types of projects, and evaluation of plant performance in this type of substrate is certainly needed and novel,” said Eric Sparks, who researches coastal estuary restoration at Mississippi State University. Sparks was not involved with the new research.

“The finding that root length in glass sand was 50% lower than in dredge sand controls really highlights the potential alternations in plant morphology that sediment substrate could influence,” he added. “Differences in root morphology could potentially influence how stable these plants are in the field when exposed to environmental factors like waves.”

“There certainly seems to be a place for recycled glass sand in the coastal restoration toolbox.”

Fronabarger said that the team wants to expand this research and test how glass-grown mangroves behave in wave flume experiments and natural environments. She also hopes to apply these same restoration ideas to other coastal areas experiencing erosion, like the Chesapeake Bay.

Is recycled glass sand a scalable solution to address coastal erosion? It depends on where you go, Fronabarger said. In cities like New Orleans with a lot of glass waste from production or consumption, it can certainly play a role. Other Gulf states like Texas, Mississippi, Alabama, and Georgia are beginning to implement large-scale glass recycling programs, too. But if there is little to no local glass to recycle, the solution is not very cost-effective.

“There certainly seems to be a place for recycled glass sand in the coastal restoration toolbox,” Sparks said.

“It’s a mindset,” Fronabarger emphasized. “It’s about taking what was once considered trash and turning it into restoration practices. I challenge people to think, ‘What have I considered trash, dilapidated or unusable, that actually can be implemented into a circular solution.’”

“It gives me a lot of hope for the future,” she said.

—Kimberly M. S. Cartier (@astrokimcartier.bsky.social), Staff Writer

Citation: Cartier, K. M. S. (2025), Glass sand grows healthy mangroves, Eos, 106, https://doi.org/10.1029/2025EO250459. Published on 12 December 2025. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

In the wake of a wildfire, a vital micronutrient can become a toxic heavy metal—and could eventually make its way into groundwater.

NASA’s Artemis mission aims to put humans back on the Moon in less than 2 years, and the China National Space Administration plans to follow suit soon after.

As astronauts return to the lunar surface for increasing periods of time, they will need structures that shield them from the Moon’s intense temperature fluctuations. In a day, temperatures can swing from 121°C (249.8°F) to −131°C (−203.8°F).

“Lunar regolith has silicon, it has oxygen elements, it has carbon. We have everything that we need to build. We just have to come up with technologies to utilize it in different ways.”

A creative solution may lie in structures made from “mooncrete,” a concrete analogue made from Moon rocks. Lunar regolith concrete (LRC) can effectively regulate temperature when exposed to dramatic fluctuations, according to new research that will be presented on 15 December at AGU’s Annual Meeting 2025 in New Orleans.

“Lunar regolith has silicon, it has oxygen elements, it has carbon. We have everything that we need to build,” said coauthor Arup Bhattacharya, a building scientist at Louisiana State University in Baton Rouge. “We just have to come up with technologies to utilize it in different ways.”

Making Mooncrete

Lunar regolith is a thick layer of rocks and dust that covers the entire lunar surface. The material is packed with minerals that make it durable, including many elements used on Earth to make concrete. To turn regolith into usable building material, scientists combine it with a binding material like sulfur, which is also available on the Moon’s surface.

Because opportunities to collect Moon rocks are few and far between, all the LRC in existence was created from 40 grams of regolith acquired during the Apollo 16 mission more than 50 years ago. Most experiments today use LRC analogues made from materials available on Earth.

This 3D printed prototype shows a lunar dome habitat that could be made from lunar regolith concrete. Credit: Arup Bhattacharya

To investigate how mooncrete might react to extreme heat and cold, the research team used data from previous experiments on lunar regolith properties to simulate a dome-shaped structure made of LRC.

The simulated structure effectively maintained an indoor temperature of 22°C (71.6°F) when subjected to the harsh lunar temperature swings. In addition, the team found that mooncrete’s insulating effects were amplified when two layers were nested on top of one another, separated by a thin layer of empty space. Heat travels less efficiently in the vacuum of space than through solid materials, so separating layers of LRC with a layer of space makes it harder for either intense heat or intense cold to penetrate the walls.

A Cost-Effective Option

Bhattacharya is “very optimistic” that structures made of lunar regolith will be built on the Moon. Using regolith is also cheaper than other options: Though estimates vary depending on the type of material, sending just 1 kilogram (2.2 pounds) of supplies to the Moon could cost more than $100,000.

“It’s the most abundant material on the Moon, its thermal conductivity is relatively small, and it can produce concrete. I think these structures will definitely be produced.”

“We could save a lot of money if we could use materials found on the Moon to build these structures,” said Adhrit Maiti, a tenth grader at Baton Rouge Magnet High School in Louisiana and first author of the study.

The study fills an important gap in lunar habitat research, said Marcello Lappa, an aerospace scientist at the University of Strathclyde in the United Kingdom who was not involved in the study. Much of the current research focuses on how to collect and process lunar regolith, yet the safety of astronauts depends on how well LRC can handle intense temperature cycles.

“It’s the most abundant material on the Moon, its thermal conductivity is relatively small, and it can produce concrete,” Lappa said. “I think these structures will definitely be produced.”

—Kaia Glickman, Science Writer

Citation: Glickman, K. (2025), Astronauts could live in structures made from Moon rocks, Eos, 106, https://doi.org/10.1029/2025EO250464. Published on 12 December 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

If it were to melt completely, the vast West Antarctic Ice Sheet (WAIS) holds enough ice to raise the global sea levels by 4 to 5 meters (13 to 16 feet).

SummaryTo better understand Eocene ophiolite emplacement and subduction initiation in northeastern Zealandia, we analysed ambient noise to image shallow (0–3 km) shear wave velocity structures of and beneath an ophiolite nappe in southern Grande Terre, New Caledonia. We assessed the uncertainties of each dispersion curve to obtain stable dispersion curves at short periods (<1 s) from a network of 17 seismic stations, whose average interstation distance is ∼15 km. We obtained 1D velocity profiles and interpolated them to generate 2D transects with a lateral resolution <2 km. Two velocity discontinuities were imaged at depths of 100 m and 400–700 m, representing surface regolith and the base of the ophiolite nappe, respectively. The ophiolite nappe is underlain by continental basement rocks in the centre of the island and sedimentary rocks near the east and west coasts. The base of the nappe shallows at ∼2.5° westward to the surface at its southwest flank. Based on the geometry of the ophiolite nappe, we suggest a down-going gravity-driven emplacement mechanism, and note similarities to allochthons in Reinga Basin and Raukumara Basin of northern New Zealand. The ophiolite nappe and underlying bedrock are more fractured on their east flank due to syn/post emplacement deformation, isostatic adjustment and present flexural bending.

SummarySeismological inversion traditionally targets either source parameters, such as location and moment tensor, or structural parameters, such as velocity and anisotropy. However, the natural formulation of Full-Waveform Inversion, often used for high-resolution structural model estimation, is to jointly invert for source and structural parameters. The common practice of holding source parameters, after initial estimation, fixed throughout the inversion inherently leads to biased solutions of the structural model, and vice versa. Whereas a joint inversion suffers from severe non-uniqueness, we demonstrate that leveraging the large amounts of data available from Distributed Acoustic Sensing (DAS) can yield robust and unbiased estimations of source and structural parameters, provided an appropriate misfit function and optimisation scheme are used. We show how the size of the data space and eventual convergence can be improved by supplementing the phase misfit objective function with amplitude information. To this end, we formulate a new misfit function, the normalised envelope. To support native DAS data implementations, we calculate the adjoint sources for the new misfit function when defined directly on strain or strain-rate data. We also show how a new approach to preconditioning as part of the L-BFGS optimisation scheme allows for effective updates of all parameters in the same iteration, despite enormous differences in their relative importance. We test our approach in a challenging synthetic noisy 2D scenario, showing a considerable reduction in source parameter errors and an improved S-wave velocity model. We also show a 3D synthetic case with an idealised DAS recording array, demonstrating a significant reduction of source parameter errors using realistic initial estimates and structural model errors. We argue that the proposed methodology can be used to improve the quality of earthquake catalogues and high-resolution structural models in seismically active regions, especially at the local-to-regional scale. None the less, computational cost remains a major challenge of the method.

A team from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) has collaborated with researchers from the University of Málaga (UMA) and the University of Córdoba (UCO) on an article published in the Journal of Sedimentary Research, which examines the relationship between the shape of sand grains and the distance traveled in the Arlanzón River (Burgos) and the Guadalhorce River (Málaga).

Some 4.6 billion years ago, Earth was nothing like the gentle blue planet we know today. Frequent and violent celestial impacts churned its surface and interior into a seething ocean of magma—an environment so extreme that liquid water could not exist, leaving the entire planet resembling an inferno.