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

The deformation of Earth materials can occur either in a “brittle” manner, mediated by fractures whose propagation radiates elastic waves, or through “intracrystalline plasticity,” governed by the motion of crystalline defects and generally considered to be largely aseismic. However, within the “brittle–plastic transition,” these mechanisms are expected to coexist. Moreover, if intracrystalline defect propagation is sufficiently rapid and accompanied by stress release, it may also theoretically generate elastic waves.

O’ Ghaffari et al. [2026] present the first experiments in which optical, mechanical, and acoustic measurements are acquired simultaneously during the propagation of intracrystalline defects (twin boundaries) in calcite single crystals. High-speed imaging, reaching up to 12,500 frames per second, is combined with multiple ultrasonic sensors sampling up to 50 million samples per second, allowing deformation processes to be resolved across a wide range of spatial and temporal scales.

The experiments capture the evolution of both brittle microcracks and crystal-plastic twins as they propagate through the crystal. Direct comparison of image sequences and acoustic records demonstrates that these two deformation mechanisms generate distinct ultrasonic signals. In particular, subtle differences in waveform characteristics are linked to the physical nature of the defect source. This distinction provides a new basis for separating brittle and plastic deformation signals in acoustic emission data. The results have important implications for laboratory studies and for interpreting acoustic monitoring data in geological and other semi-brittle materials.

Citation: O’ Ghaffari, H., Peč, M., Cross, A. J., Mittal, T., & Mok, U. (2026). Brittle and crystal-plastic defect dynamics of calcite single crystals. Journal of Geophysical Research: Solid Earth, 131, e2025JB032846. https://doi.org/10.1029/2025JB032846

—Marie Violay, Associate Editor, JGR: Solid Earth

Text © 2026. 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.

An unusual failure has occurred on a cut slope adjacent to a key road in Greece.

On 2 February 2026 a major, fascinating landslide occurred on the A5 Ionian motorway between Arta and Amfilochia in Greece. The location appears to be [39.07754, 21.09861]. The news site ekathimerini has a story providing the details, which includes this extraordinary image of the aftermath of the landslide:-

The 2 February 2026 landslide on the Ionian motorway in Greece. Image from ERT via ekathimerini.

I believe that the Google Earth image below shows the configuration of the site in 2023:-

Google Earth image showing the site of the 2 February 2026 landslide on the Ionian motorway in Greece.

So, this is a large cut slope that appears to have been formed in about 2015 (based on Google Earth imagery). The failure is quite complex, with most of the landslide moving as a large block (which has fractured in the late stage of movement). There is a large displacement on the far side of the landslide (in the photograph view), so there has been some rotation around an approximately vertical axis. The landslide does not appear to have been conventionally rotational.

To me, this suggests failure on an existing plane of weakness in the slope. The news report indicate that the landslide occurred after heavy rainfall.

This is a Google Streetview of the landslide site from September 2023:-

Google Streetview image showing the site of the 2 February 2026 landslide on the Ionian motorway in Greece.

It appears that the slope has rockbolts, which suggests that there was an awareness of the potential for instability. Perhaps they were insufficiently long to prevent this failure? The presence of the rockbolts may explain why the landslide moved as a predominantly intact block, though.

The Ionian motorway is now closed. There are similar slopes along the road, so the investigation of this failure may have wider implications.

Return to The Landslide Blog homepage Text © 2026. 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.

An agreement on the third implementation phase of Destination Earth (DestinE), the European Commission's initiative to develop a highly accurate digital twin of Earth, has been signed between the European Commission and the European Centre for Medium-Range Weather Forecasts (ECMWF). The third phase will start in June 2026 and end in June 2028.

When extreme weather strikes, the preparations of emergency planners can have life-or-death consequences. In July 2025, central Texas flooded with disastrous consequences, killing more than 130 people.

SummaryLandslide disasters are typically triggered by various environmental factors, making it crucial to understand the interaction between subtle internal changes and these factors for accurate risk assessment. Noise-based velocity change measurement offers a promising tool, yet its widespread application is limited by the inherent instability of noise sources, constraining temporal resolution. Here, we employ an wave-packet-based nine-component spatial stacking approach with a dense seismic array deployed at the Xishan Village landslide. This advancement allows for the extraction of extraction of high temporal velocity change (20-minute) at different frequencies, enabling four-dimensional dynamic analysis of landslide internal changes. Our findings reveal complex spatial distributions of velocity changes influenced by solar thermal radiation and rainfall at different locations and depths. Notably, during rainfall of approximately 20 mm, the observed maximum velocity reduction correlates closely with a fracture zone at ∼8 m depth, suggesting that pre-existing deformation structures significantly enhance local permeability, and promote the now deeper rainwater infiltration. This infiltration leads to increased pore pressure and velocity reduction. These results highlight the ambient noise method potential for urban landslide monitoring, providing technical support for early warning and risk assessment.

A study on tectonic plates that converge on the Tibetan Plateau has shown that Earth's fault lines are far weaker and the continents are less rigid than scientists previously thought. This finding is based on ground-monitoring satellite data. The study, published in Science, includes several high-resolution maps based on data from Copernicus Sentinel-1 satellites. It shows how the region is being stretched and squeezed by Earth's geological movements.

A research team from University of Tsukuba and collaborating institutions has clarified why M9-class megathrust earthquakes recur off the Kamchatka Peninsula with an unusually short cycle of 73 years. By analyzing the rupture process of the 2025 event, the team demonstrated that this earthquake exhibited complex behavior that cannot be explained by conventional seismic-cycle models.

In recent years, numerous landslides on hillsides in urban and rural areas have underscored that understanding and predicting these phenomena is more than an academic curiosity—it is a human necessity. When unstable slopes give way after intense rainfall, the consequences can be devastating, with both human and material losses. These recurring tragedies led us to a simple yet powerful question: Can we build landslide susceptibility maps that are more objective, transparent, and useful for local authorities and residents?

A study in Nature Geoscience reveals that changes in the West Antarctic Ice Sheet (WAIS) closely tracked marine algae growth in the Southern Ocean over previous glacial cycles, but not in the way scientists expected. The key factor is iron-rich sediments transported by icebergs from West Antarctica.

Water vapor (H2Ov) is an essential component of Earth's atmosphere, playing critical roles in climate regulation, weather patterns, and the water cycle. Its sources primarily come from natural processes such as ocean evaporation and terrestrial evapotranspiration. However, during the fossil fuels (e.g., coal, petroleum, natural gas) combustion process, in addition to emitting substantial amounts of CO2, they also generate significant amounts of water vapor as a byproduct (combustion-derived water vapor sources: CDWV).

An ongoing string of more than a dozen earthquakes in less than 90 minutes early Monday ended what had been some recent calm from recent weeks of shaking ground in the region, according to the U.S. Geological Survey.

A study by the Institut Català de Paleontologia Miquel Crusafont (ICP-CERCA) with the involvement of the UAB indicates that between 12.5 and 9 million years ago, in the Vallès-Penedès basin, rainfall was twice as high as it is today, and the climate was subtropical. The research has reconstructed the precipitation and climatic conditions of the past from fossils of small mammals found throughout the area. The research is published in the Journal of Mammalian Evolution.

A research team from the Aerospace Information Research Institute of the Chinese Academy of Sciences (AIRCAS) has developed a new method combining deep learning with physical radiative transfer modeling to improve the retrieval of atmospheric aerosol properties from complex satellite observations, supporting high-resolution, near-real-time monitoring of haze and dust events. The study was recently published in Journal of Remote Sensing.

Some tropical land regions may warm more dramatically than previously predicted, as climate change progresses, according to a new CU Boulder study that looks millions of years into Earth's past. Using lake sediments from the Colombian Andes, researchers reveal that when the planet warmed millions of years ago under carbon dioxide levels similar to today's, tropical land heated up nearly twice as much as the ocean.

A research group has revealed through seismic wave analysis that the oceanic plate beneath the Ontong Java Plateau—the world's largest oceanic plateau—was extensively altered by massive volcanic activity during its formation. The study is published in Geophysical Research Letters.

Dalhousie researchers have revealed how Arctic aquifers—permeable layers of the ground that store and transmit water to rivers, lakes and terrestrial ecosystems—behave today and how these vital resources will change with warming temperatures and sea-level rise.

Earth's ocean absorbs carbon dioxide from the atmosphere, helping to temper the impact of climate change but increasing ocean acidity. However, calcium carbonate minerals found in the seabed act as a natural antacid: Higher acidity causes calcium carbonate to dissolve and generate carbonate molecules that can neutralize the acid.

Climate experts have identified an atmospheric configuration that can release huge volumes of water in a matter of minutes. Led by Newcastle University and the UK Met Office, the research helps explain some of the world's most dangerous flash-flood events and may aid future improvements in identifying risk. It offers forecasters new insights and could in the future help communities mitigate against extreme weather events.

At a natural underwater laboratory off the coast of Papua New Guinea, researchers examined what happens to a diverse reef ecosystem as it experiences gradually increasing levels of ocean acidification. They found that as the pH decreased, complex branching corals, soft corals, and young corals died off. In their place grew hardy boulder corals and non-calcium-based algae.

One thing the team didn’t find: a specific tipping point at which corals began to die off.

“That was something we really hoped to be able to detect from the data,” said Sam Noonan, a coral reef ecologist at the Australian Institute of Marine Science (AIMS) in Townsville and lead researcher on a new study reporting the work. “Do you have this increase in acidification and everything seems fine, and then species start falling off a cliff? But that was not the case at all. With every little increase, we saw a smooth decline.”

These observations, which took place near a volcanic seep that leaks carbon dioxide (CO2) into the ocean from the seafloor, provide a preview of how reefs around the world could respond as the ocean absorbs increasing quantities of atmospheric CO2.

Researchers placed instruments like this one at 37 locations along the volcanic seep to measure the water’s pH. Credit: © AIMS | Katharina Fabricius, CC BY 3.0 AU A Natural Coral Laboratory

The ocean is the world’s largest carbon sink. As atmospheric CO2 concentrations continue to rise, the ocean absorbs more and more of that carbon, which makes seawater more acidic. Oceanographers and marine ecologists have observed for decades that falling marine pH levels disturb delicate marine ecosystems, like coral reefs, around the world.

Coral reef scientists have observed in laboratory settings that acidic seawater makes it harder for corals to build the carbon-based limestone skeletons that support complex branching corals.

“Even the most advanced of these experiments, however, cannot fully capture the incredible complexity of a real-world coral reef, where biodiverse flora and fauna are interacting in an ever changing array of environmental conditions,” said Ian Enochs, a coral ecologist at NOAA’s Atlantic Oceanographic and Meteorological Laboratory in Miami.

To overcome those limitations, Noonan and his AIMS colleagues traveled to Milne Bay on the southeastern coast of Papua New Guinea, which is home to a diverse and thriving coral reef ecosystem. It’s also home to a volcanic seep that releases nearly pure CO2 gas from vents in the seafloor.

A reef like this one is “a natural laboratory that allows us to understand how real coral reefs respond to acidification.”

A reef like this one is “a natural laboratory that allows us to understand how real coral reefs respond to acidification,” Enochs said. Enochs was not involved with the new research.

The scientists spent more than a decade measuring the ambient properties of the seawater throughout the reef and documenting, via a proxy called aragonite saturation, how acidity changes on the basis of proximity to a seep. Aragonite saturation levels across the seep match values predicted to occur by 2100 under a wide range of carbon emission scenarios.

The team set up 37 monitoring stations at locations along the reef that experience gradually rising levels of CO2. Those stations measured seawater properties like temperature, light exposure, current, and, of course, acidity. Divers documented coral diversity, the abundance of juvenile corals, and the types of algae that grew around each of the stations.

In laboratory experiments, “you have a control reef, and then you have an acidified reef, and it’s just A versus B,” Noonan said. “In this study, we have 37 stations across this gradient to look at community change on a continuum. There’s no data out there like that.”

In locations along the reef where ocean pH was at ambient levels, like this location hundreds of meters away from the volcanic seep, the reef exhibited high structural complexity, abundant branching corals and soft corals, and many small young corals. This location was used as a control site. Credit: © AIMS | Katharina Fabricius, CC BY 3.0 AU

At stations more than 500 meters (1,640 feet) from the volcanic seep, the reef hosted a diverse array of complex branching corals, soft-bodied corals, and juvenile corals. Closer to the seep, stations recorded progressively lower pH levels and the complex and delicate corals died off. The only surviving corals were hardier boulder corals (genus Porites), which have thick layers of tissue between the water and their skeletons. There were also fewer juvenile corals and more non-carbon-based algae as acidity rose.

“You can visually see it when you’re swimming around these systems,” Noonan said, and the data back up those observations. “It seems that some species are more susceptible than others. Those with a really high surface area and a thin tissue layer seem to be really affected.”

“Those species that are most affected seem to be the most ecologically important.”

“The problem is those species that are most affected seem to be the most ecologically important,” he added. “They’re the ones that provide shelter for the literally millions of species that live on coral reefs. All the fish and little crustaceans, they all rely on these things for habitat, and they’re the ones that are really starting to drop out first.”

These results were published in Communications Biology in November 2025.

An Ongoing Problem

“This paper is important because it offers another glimpse into the future of reefs under acidification, one that is entirely independent from prior experiments and other investigations of similar sites,” Enochs explained. “What the authors found, however, is remarkably similar to what we’ve observed in our experimental tanks, and at other naturally acidified sites from all over the world.”

“It’s the similarity of these stories that gives these findings the greatest power, parallel lines of evidence all pointing to the same thing.”

“It’s the similarity of these stories that gives these findings the greatest power, parallel lines of evidence all pointing to the same thing,” Enochs added.

Millions of people depend on reef ecosystems to support fisheries, feed coastal communities, protect coastal infrastructure from waves and storm surge, and sustain tourism and local economies. What’s more, “lower coral cover means less shelter for the exceptional biodiversity of a reef, and a loss of species, many of which are still unknown to science,” Enochs said. “When I read this paper and I see how acidification impacts these reefs, I think about what it could mean for other reef ecosystems and the communities they support.”

Noonan said that this volcanic seep is a simple proxy for ocean conditions under a future climate scenario, but it’s not a perfect one. Sunlight and temperature were pretty constant across the reef, which was good for isolating the effects of CO2 but not realistic for most reef ecosystems.

Future work could consider those additional variables to see whether there is a true acidification tipping point for corals. But Noonan also brought up a more concerning possibility.

“This has been ongoing since the Industrial Revolution, so perhaps there were tipping points and we’re already past them.”

“This has been ongoing since the Industrial Revolution, so perhaps there were tipping points and we’re already past them,” he suggested. There’s no way to know, as scientists lack data on past ocean acidification.

Regardless, “these changes are ongoing and occurring now,” he added. “We’re starting to detect significant, statistical changes in these communities at [acidification] values that we’re expecting within the next 20 to 30 years on coral reefs. It’s not end of the century stuff.”

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

Citation: Cartier, K. M. S. (2026), Coral diversity drops as ocean acidifies, Eos, 107, https://doi.org/10.1029/2026EO260047. Published on 2 February 2026. Text © 2026. 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.

There are a few things scientists know for sure about how Earth grows warmer: For instance, when there’s more carbon dioxide (CO2) in the atmosphere, that CO2 traps heat. This means that during an ice age, less CO2 is present in Earth’s atmosphere.

“One of the fundamental questions in our field was, ‘Where did that CO2 go during ice ages, and where did it come from when the planet warmed?’”

“One of the fundamental questions in our field was, ‘Where did that CO2 go during ice ages, and where did it come from when the planet warmed?’” said Ryan Glaubke, a paleoceanographer and postdoctoral researcher at the University of Arizona.

Scientists had their suspicions: The ocean was the obvious culprit because it’s enormous and is known to exchange CO2 with the atmosphere. But for CO2 to be stored in the ocean for long periods, it would need to be in cold, salty, dense water far beneath the ocean’s surface. Until now, scientists had no way to prove that salinity levels in the deep ocean were linked to changes in atmospheric CO2 over the scale of ice ages.

Now, new research published in Nature Geoscience seems to confirm what many researchers have long thought was the case: A giant “blob” of salty ocean water kept carbon dioxide locked deep in the ocean during the last ice age, and the blob released that CO2 during an upwelling event 18,000 years ago.

Unusual Upwelling

During his graduate studies at Rutgers University, Glaubke and his fellow researchers collected sediment cores from the seafloor. Sediment cores are long, thin cylinders of mud with successive layers that reflect periods in Earth’s history.

Normally, when scientists collect sediment cores, they use them to learn about past conditions near the ocean’s surface. Single-celled creatures called foraminifera (or forams, for short) live and build their shells near the ocean’s surface. When these creatures die and sink to the ocean floor, their shells become part of the seafloor sediment and provide a record of the composition of the upper ocean.

This team, however, gathered sediment cores from an unusual site on the boundary of the Indian and Southern oceans. In this spot, off the coast of Western Australia, waters from deep in the ocean upwell to the surface.

“It’s really hard to look at the bottom of the ocean from the surface,” said Liz Sikes, a paleoceanographer at Rutgers, a coauthor of the paper, and Glaubke’s former Ph.D. adviser. “But the thing is, these planktic forams are in a place in the ocean where the water that’s at the surface has just returned to the surface and it still retains most of its deep-water qualities.”

Gathering sediment cores from this location meant the scientists could gain an understanding not just of how the upper ocean changed in the past but of how the waters that rose from the bottom of the ocean had also changed.

“What we found, rising from the deep ocean to the surface, was not only this geochemical fingerprint for old carbon that remained at the bottom of the ocean, but at the exact same time, we see this increase in upper ocean salinity by around 2 parts per thousand, which is a very large scale change,” Glaubke said. “That is one of the really important contributions of this paper, I think, which is that it provides this support for this ‘salty blob’ kind of retention mechanism.”

From Glacial to Interglacial

Patrick Rafter, a chemical oceanographer who did not contribute to this paper but was involved with measuring the radiocarbon levels in the collected sediment cores, said he was already convinced that salinity must play an important role in the rate of global ocean overturning, so the results were “not surprising” to him. He noted that the study was rigorous and careful, in that the researchers replicated their anomalous findings with multiple planktic species.

“It’s like any kind of mystery: The more evidence you get supporting it, the more likely you are to think maybe it’s real.”

“It’s like any kind of mystery: The more evidence you get supporting it, the more likely you are to think maybe it’s real,” he said. “So far, the evidence that exists suggests this is a solid finding that we should consider when trying to explain glacial-interglacial climate change.”

Furthermore, the upwelling waters of the Southern Ocean help sustain a global conveyor belt of currents, including the Atlantic Meridional Overturning Circulation. During an ice age, these currents tend to be more sluggish. The strengthening of these currents is an important piece in moving the planet out of an ice age.

“We make the argument that not only is this water mass releasing carbon to the atmosphere and kind of warming the planet, but the salt that then gets entrained in the global conveyor belt probably played a really important role in flipping that switch from glacial mode to interglacial mode,” Glaubke said. “So there’s this dual contribution that the salty blob might be making to ending the last ice age.”

—Emily Gardner (@emfurd.bsky.social), Associate Editor

Citation: Gardner, E. (2026), How the rise of a salty blob led to the fall of the last ice age, Eos, 107, https://doi.org/10.1029/2026EO260044. Published on 2 February 2026. Text © 2026. 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.