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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.

Ammonia-oxidizing archaea (AOA) are some of the most abundant microorganisms in the ocean and play a key role in nitrogen cycling. Yet, despite their ubiquity, scientists have long puzzled over how these microbes can flourish in the nutrient-poor waters of the open ocean, where their main nitrogen and energy source, ammonium, is often vanishingly scarce.

In an age of rising sea levels, as polar ice sheets melt in a climate warmed by fossil fuel emissions, climate modelers are racing to understand what the future might hold for coastlines around the world. But uncertainties about how fast polar ice might melt make predicting coastal inundation difficult. Now, scientists think they've helped make one of those uncertainties, the material conditions underneath the Greenland ice sheet, smaller.

Around the world, phytoplankton in the upper ocean help to cycle key nutrients and regulate Earth's climate by absorbing carbon dioxide. These photosynthesizing organisms rely on dissolved iron as an essential micronutrient, meaning that when iron levels drop, phytoplankton activity drops, too.

Sophisticated new chemical analysis of gases trapped in rocks for millions of years has cast new light on the origin of the gold deposits beneath Scotland and Ireland. The finding, made by team of scientists led by Professor Fin Stuart from the University of Glasgow, could help pinpoint the location of buried deposits of the treasured metal in the future.

Want to find schools in satellite images? Researchers say you can spot them by looking at tree cover because schools stand out as rectangular holes in the urban canopy.

Even though access to nature offers a variety of health and social benefits for students, researchers at the University of California (UC), Davis have found that trees on school grounds are declining across California. Declining tree canopy at schools can raise temperatures to dangerous levels, forcing kids to miss out on the benefits of spending time outside.

The researchers also conducted a field study to show how much schoolyard trees influence temperature. “Our motivation is thinking about a kid of around 8 years old playing in the schoolyard with their friends,” said UC Davis urban forestry scientist Luisa Velasquez-Camacho. “It’s very nice, but when you translate this scenario to Sacramento or the Central Valley at 2:00 p.m. in the hottest months, this is a nightmare because they don’t have natural shade.”

“Shade Is King”

To track changes in tree cover at schools, the researchers examined CalFire (California Department of Forestry and Fire Protection) tree canopy maps for more than 7,200 urban schools in California between 2018 and 2022. By quantifying the tree cover, they found that 85% of the schools had experienced tree loss over that time span, and some Central Valley school districts lost 25% of their tree cover. Schools had less than half the tree cover of surrounding urban areas. The results were published in Urban Forestry and Urban Greening.

“I can’t say the results are surprising,” said Kevin Lanza, an assistant professor of environmental and occupational health science at UTHealth Houston who wasn’t involved in the study. He said the findings align with existing studies on urban forestry and noted that trees can be lost in schools to make way for building expansions or because the cost of maintaining them is prohibitive. “Schools are more stressed than ever,” he said.

Scientists collected data such as temperature, radiation, and wind at children’s height. Credit: Emily C. Dooley, UC Davis

The researchers wanted to do more than document the loss of tree cover in schools; they wanted to investigate the health cost of losing those trees. To that end, said Alessandro Ossola, an ecologist at UC Davis and a coauthor of the research, “we took to the streets” in the summer of 2025, spending long days collecting weather data at school playgrounds across California.

The researchers deployed sensors collecting data on air temperature, humidity, radiation, and wind placed at children’s height around each playground. Using these data, they were able to calculate the thermal index, which is a measure of how the environment feels to a human body.

Then, they walked a sensor-laden cart around each playground—racking up over 200 miles (322 kilometers) over the summer—to map out microclimates. The researchers also scanned thermal radiation from common playground surfaces, including dry and irrigated grass, mulch, asphalt, and rubber.

Researchers walked a sensor-laden cart over 200 miles (322 kilometers) this summer while studying California playground temperatures. Credit: Jael Mackendorf, UC Davis

Although the team hasn’t fully analyzed the data yet, early results indicate that rubberized surfaces, often found around playground equipment, are particularly dangerous for reflecting radiation. “It was ridiculous for us to stay out there in the afternoon, even as adults. A kid is much closer to the ground,” Ossola said.

They saw the heat index reach 120°F (54°C) at some schools, and a single tree could drop surface temperatures by as much as 30°F (17°C) compared to direct sunlight. But while the air temperature often wasn’t dramatically different between direct Sun and shade, the thermal index dropped considerably under the shade because of the effects of radiation.

“Shade is king.”

“Shade is king,” said Lanza, and while artificial shade is better than nothing, trees can lower temperatures even more because the water vapor produced by evaporation from the tree leaves absorbs even more heat.

Once trees are lost, planting and maintaining replacement trees until they grow big enough to offer shade are a major hurdle. The researchers suggested that after their full analysis, the results could help guide schools on where to plant new trees and what species of trees will provide the greatest benefits.

Finding a Schoolyard Shade Strategy

Finding ways to manage temperatures is vital for children’s development because if temperatures rise too high, students are forced to remain inside, and for many, recess is their only chance to be in nature. Time spent in nature increases well-being and helps build healthy physical activity habits. UC Davis researchers are also conducting studies that suggest time outside can improve academic performance.

“It’s a matter of reenvisioning trees as an asset that can be budgeted.”

Lanza also noted that “low-income and Black and Latino communities are seeing larger losses of canopy than other communities,” indicating that the impacts of losing time in nature are likely not equitable across populations.

The ongoing work by universities and Green Schoolyards America, a nonprofit partner in this research, aims to use the findings to advocate for strategic investments in trees and other plants to improve students’ time spent outside. “It’s a matter of reenvisioning trees as an asset that can be budgeted,” Ossola said. “If we are negating these opportunities to be close to nature, we are missing the bus, not just for academic outcomes but also in terms of public health in the future.”

—Andrew Chapman (@andrewgchapman.bsky.social), Science Writer

This news article is included in our ENGAGE resource for educators seeking science news for their classroom lessons. Browse all ENGAGE articles, and share with your fellow educators how you integrated the article into an activity in the comments section below.

Citation: Chapman, A. (2025), California schools are feeling the heat, Eos, 106, https://doi.org/10.1029/2025EO250458. Published on 11 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.

Source: Geophysical Research Letters

Around the world, phytoplankton in the upper ocean help to cycle key nutrients and regulate Earth’s climate by absorbing carbon dioxide. These photosynthesizing organisms rely on dissolved iron as an essential micronutrient, meaning that when iron levels drop, phytoplankton activity drops, too.

However, the full details of dissolved iron dynamics in the upper ocean are unclear, limiting our understanding of the effects on phytoplankton ecology, nutrient cycling, and the climate.

Now, Bates and Hawco report a new analysis of dissolved iron levels in the upper ocean near Hawaii. Between 2020 and 2023, they collected seawater samples on 21 separate research cruises to Station ALOHA (A Long-Term Oligotrophic Habitat Assessment), a marine research site located 100 kilometers north of Oahu, Hawaii. Back in the lab, they measured levels of dissolved iron and other elements in the samples and compared samples collected during different seasons.

The analysis reconfirmed a well-documented increase in dissolved iron levels at Station ALOHA in the springtime, which is caused by an annual increase in dust carried to the site by winds from Asia. However, the new data also revealed a previously undetected spike in dissolved iron in the winter that could not be explained by dust deposition.

Further analysis of the samples, including measurements of ratios between titanium and aluminum levels, suggested that the wintertime iron peak may have a far more local source: the Hawaiian Islands themselves. It is possible that increased wintertime rainfall boosts runoff of sediment from the islands, which is then transported to Station ALOHA by wintertime swells.

The researchers also used the new data to estimate that despite seasonal fluctuations in concentration, dissolved iron tends to cycle through the upper ocean at a relatively steady rate, with each molecule being replaced about every 5 months. Prior estimates reported turnover rates of anywhere from days to decades.

These findings could help improve understanding of phytoplankton’s various ecological roles, including nitrogen cycling and carbon uptake. (Geophysical Research Letters, https://doi.org/10.1029/2025GL118095, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Wintertime spike in oceanic iron levels detected near Hawaii, Eos, 106, https://doi.org/10.1029/2025EO250462. Published on 11 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.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Solid Earth

The Nankai subduction zone in southwest Japan has produced multiple M8+ earthquakes over the past 300 years, including the 1707 M8.7 Hōei earthquake, the 1944 M8.1 Tōnankai earthquake, and the 1946 M8.1 Nankaidō earthquake. As one of the most extensively studied subduction zones in the world, it has been the focus of numerous Integrated Ocean Drilling Program (IODP) expeditions aimed at improving our understanding of its seismogenic and tsunamigenic behavior.

Faulkner et al. [2025] compile all available laboratory friction data from Nankai Trough scientific drilling samples and integrate them with routine IODP mineralogical analyses. The dataset spans three transects—Kumano, Muroto, and Ashizuri—and includes material from 26 drilling sites. The experiments cover a wide range of slip velocities, from micrometers per second to meters per second, allowing systematic inversion of key frictional parameters.

This compilation shows that the frictional strength of these materials is generally lower than typical Byerlee friction and decreases with increasing clay content. However, the tendency for materials to weaken at higher slip rates—a key condition for earthquake nucleation—does not clearly correlate with clay abundance. Frictional stability analyses indicate a broad spectrum of possible fault-slip behaviors, from slow slip to earthquake-like failure, consistent with observations in nature. Overall, the findings highlight significant natural heterogeneity in frictional properties within a subduction environment and provide new constraints on the frictional characteristics of the shallow Nankai margin.

Citation: Faulkner, D. R., Zhang, J., Okuda, H., Bedford, J. D., Ikari, M. J., Schleicher, A. M., & Hirose, T. (2025). Synthesis of the laboratory frictional properties of a major shallow subduction zone: The Nankai Trough, offshore SW Japan. Journal of Geophysical Research: Solid Earth, 130, e2025JB031613. https://doi.org/10.1029/2025JB031613

—Alexandre Schubnel, Editor-in-Chief, JGR: Solid Earth

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.

As part of the EU project ECOTIP, an international team of researchers, including the Helmholtz-Zentrum Hereon, has analyzed the sea off Greenland more comprehensively than ever before. The key question: How is the area developing in the face of climate change and environmental pollution? Most of the samples were examined in the Hereon laboratories.

Recent fieldwork by Griffith University researchers has highlighted an African country that is facing a rapidly escalating environmental crisis as severe gully erosion—locally termed "mega gullies"—advances across valuable agricultural landscapes.

SummaryTo understand the melt source of hotlines with asynchronous volcanoes, we investigate the lithospheric structure of the Cameroon Volcanic Line (CVL), an intraplate hotline without age progression stretching from the Atlantic Ocean into Central Africa. We analyze Bouguer gravity anomalies from the World Gravity Model 2012 using the 2‐D power spectrum techniques and 2-D forward modeling to estimate the crustal and lithospheric thickness. We find: (1) thin crust (20–30 km) beneath the oceanic CVL; (2) thick crust (30–43 km) beneath the continental CVL and the Oubanguides Belt, and thicker crust (43–50 km) beneath the Congo Craton; (3) thin lithosphere (90–120 km) beneath the oceanic CVL and thinner lithosphere (75–90 km) beneath the continental CVL; and (4) thicker lithosphere (150–234 km) beneath the Congo Craton. Our seismically constrained forward models reveal a delaminated body beneath the continental CVL and a sharp transition from thick lithosphere beneath the Congo Craton to thin lithosphere beneath the Oubanguides Belt. We interpret that the thin lithosphere beneath the continental CVL is a result of lithospheric delamination. The delaminated body in the uppermost mantle deflects rising mantle plume material, resulting in the Y-shaped distribution of continental volcanoes. Edge-Driven Convection (EDC) resulting from the sharp gradient in lithospheric thickness between the Congo Craton and the Oubanguides Belt focuses the plume material beneath thin lithosphere, producing the continental CVL. The southern volcanoes of the continental CVL are formed from the southward deflection of plume material by the delaminated body, with melt ascent facilitated by the lithospheric-scale Central African Shear Zone. The northward-directed plume material forms the distinct Biu Plateau, and the eastward-deflected plume material forms the Adamawa Plateau. With a continuous influx of plume material beneath the thin continental lithosphere, for mass to be conserved, part of the plume material defiles the gradient of the thicker oceanic lithosphere adjacent to the Congo Craton to flow oceanward. The oceanward flow of plume material is modulated by upwellings from EDC, producing the oceanic CVL, which explains the oceanward decrease in the timing of the onset of volcanism. We therefore conclude that only the continental CVL lacks age progression resulting from the complex interaction of the rising plume with the delaminated body and the lithospheric architecture.

SummaryInferring the spatio-temporal distribution of slip during earthquakes remains a significant challenge due to the high dimensionality and ill-posed nature of the inverse problem. As a result, finite-source inversions typically rely on simplified assumptions. Moreover, in the absence of ground-truth measurements, the performance of inversion methods can only be evaluated through synthetic tests. Laboratory earthquakes offer a valuable alternative by providing “simulated real data” and ground truth observations under controlled conditions, enabling a more reliable evaluation of source inversion procedures. In this study, we present static and quasi-static slip inversion results from data recorded during laboratory earthquakes. Each event is instrumented with 20 accelerometers along the fault, and the recorded acceleration data are used to invert for the slip history. We consider two different types of Green’s functions (GF): simplistic GF assuming a homogeneous elastic half-space and realistic GF computed by finite element modeling of the experimental setup. The inversion results are then compared to direct observations of fault slip and rupture velocity obtained independently during the experiments. Our results show that, regardless of the GF used, the inversions fit well with the data and result in small formal uncertainties of model parameters. However, only the inversion with realistic GF yields slip distributions consistent with the true fault slip measurements and successfully recovers the distribution of rupture velocity along the fault. These findings emphasize the critical role of GF selection in accurately resolving slip dynamics and highlight an important distinction in Bayesian inversion: while posterior uncertainty quantification is essential, it does not guarantee accuracy, especially if forward modeling uncertainties are not properly accounted for. Thus, confidence in inversion results must be paired with careful modeling choices to ensure physical reliability.