Feed aggregator

When an extreme weather event occurs, the probability or risk of other events can often increase, leading to what researchers call "cascading" hazards.

Scientists have identified what could be the oldest rocks on Earth from a rock formation in Canada.

At this year's Living Planet Symposium, attendees heard how ESA's Next Generation Gravity Mission could provide the first opportunity to directly track a vital ocean circulation system that warms our planet—but is now weakening, risking a possible collapse with far-reaching consequences.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

Deep earthquakes are still a mystery that has been debated for a long time, but no consensus has been made so far. They originate at depths of 500 to 700 kilometers where there are extreme pressure and temperature conditions that should prevent the failure mechanisms that generate shallow earthquakes. Despite decades of observations and various proposed theories, a coherent mechanism that accounts for deep earthquake magnitudes has yet to be identified.

Jia et al. [2025] present an unprecedented analysis of 40 deep earthquakes worldwide with large magnitudes. They find that most of them are governed by a common mechanism facilitated by shear thermal runaway, ultimately allowing earthquakes to grow larger and release more energy. This explanation applies to deep earthquakes across diverse environments, from the coldest slabs such as Tonga, to the warmest, including those beneath South America.

Citation: Jia, Z., Fan, W., Mao, W., Shearer, P. M., & May, D. A. (2025). Dual mechanism transition controls rupture development of large deep earthquakes. AGU Advances, 6, e2025AV001701. https://doi.org/10.1029/2025AV001701

—Alberto Montanari, Editor-in-Chief, AGU Advances

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.

Scientists for the first time have detected a slow slip earthquake in motion during the act of releasing tectonic pressure on a major fault zone at the bottom of the ocean.

A new review published in Advances in Atmospheric Sciences sheds light on one of climate science's enduring puzzles: how the patterns of tropical ocean warming influence the behavior of tropical cyclones (TCs) in a warming world. An international team of scientists synthesizes decades of observational evidence and climate modeling advances to chart a path forward for more reliable TC projections.

As wildfires increasingly threaten lives, landscapes, and air quality across the U.S., a Stanford-led study published in AGU Advances finds that prescribed burns can help reduce risks.

A new study challenges the idea that climate change is behind the erratic wintertime behavior of the polar jet stream, the massive current of Arctic air that regulates weather for much of the Northern Hemisphere.

Lake Tahoe’s sparkling, clear water is a point of pride among locals and a draw for tourists. Although the water clarity—measured by how deep visible light can penetrate—has decreased since measurements began in 1968, conservation efforts over the past 2 decades have stabilized it.

However, a new study published last month in Limnology and Oceanography Letters shows that ultraviolet (UV) light tells a different story. The depths to which UV radiation reaches in Lake Tahoe vary dramatically between extreme wet and dry years. Because UV radiation can affect chemical and biological processes, shifting underwater light environments between years could have significant implications for Lake Tahoe’s ecosystem.

A Question of Clarity

To measure water clarity in Lake Tahoe, a 1,645-foot-deep (594-meter-deep) freshwater lake straddling the border of California and Nevada in the Sierra Nevada Mountains, scientists drop a white disk into the water and record how deep they can see it. They use a similar approach to measure UV light, but because it’s invisible to our eyes, they drop a sensor that measures different wavelengths of UV light as it sinks.

Eighteen years ago, scientists at the University of California, Davis Tahoe Environmental Research Center began collecting UV data from the lake every 2 to 3 weeks, creating a long-term record rare for lakes anywhere in the world.

“You can use satellites to look at long-term trends in water clarity, and people have done that all over the U.S. and around the world,” said Kevin Rose, a freshwater ecologist at Rensselaer Polytechnic Institute in New York, but “a multidecade record of UV radiation is a unique asset.” Rose was not involved in the study.

“We found a huge fluctuation in UV transparency year to year.”

Several studies have used data from the record, but limnologist Shohei Watanabe at the Tahoe Environmental Research Center and his colleagues wanted to do a comprehensive analysis of whether Lake Tahoe was experiencing changes in the penetration of UV light between 2006 and 2023.

Watanabe initially expected to see a gradual decrease in UV penetration over the study period, mirroring the trend in visible light. “Instead, we found a huge fluctuation in UV transparency year to year,” he said.

In drought years, such as 2014–2015, UV radiation penetrated deeper than in exceptionally wet years such as 2017, when the Sierra Nevada received its second-highest amount of precipitation since 1910.

“It’s an amazing difference,” Watanabe said. The most dramatic differences occurred during the spring and early summer, when solar radiation is at its strongest. UV radiation was 100 times stronger 10 meters (32 feet) below the surface and reached up to nearly 4 times deeper in summers during drought years.

Shohei Watanabe and other scientists have been collecting data on UV radiation in Lake Tahoe for 18 years. Credit: Karin Higgins

The phenomenon occurs because wet years wash more particulates and dissolved organic matter off the slopes of the surrounding mountains and into the lake, which blocks the UV radiation.

Visible light showed only a twofold difference in how deep it penetrated the lake between wet and dry years because the longer wavelengths of visible light are not as easily blocked by dissolved organic matter in the water. To the naked eye, visitors might notice some changes in the water clarity between years, “but it’s not like a 100-fold difference,” Watanabe said.

A Sunburn on the Ecosystem

The balance of UV light and visible light is crucial in freshwater ecosystems. UV radiation breaks down dissolved organic matter, releasing carbon dioxide into the atmosphere. Just like UV light can give us a sunburn, it can harm freshwater organisms by damaging DNA and inhibiting photosynthesis. It can also affect zooplankton behavior—these organisms actively avoid harmful UV light by migrating deeper during the day.

For the most biologically damaging UV wavelengths, including 305 and 320 nanometers, the differences from year to year in Lake Tahoe were most pronounced.

UV radiation isn’t always harmful to the ecosystem, however. Rose noted previous research showing that it prevents invasive fish, such as bluegill, from successfully reproducing in Lake Tahoe’s clear waters because larvae don’t survive high UV exposure. The fish become restricted to murky nearshore areas such as marinas.

“I really want to stress the importance of long-term monitoring for this kind of environmental study.”

Drastic shifts in UV penetration between wet and dry years therefore imply big changes in the ecosystems in the lake—and those swings could get more intense with human-caused climate change. “When we think about Lake Tahoe, now, going through precipitation cycles, that also means potential biological damage,” Rose said. Fully understanding how these communities will react will require continued monitoring.

Similar UV cycles might also occur in other clear mountain lakes worldwide, but each lake system has unique characteristics that would influence light patterns. “I really want to stress the importance of long-term monitoring for this kind of environmental study,” Watanabe said.

Watanabe and his colleagues are now planning and performing studies to determine how these UV variations affect Lake Tahoe’s carbon cycle, primary productivity, and other biological processes. “That’s the next step,” he said.

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

Citation: Chapman, A. (2025), Precipitation extremes drive swings in Lake Tahoe’s UV exposure, Eos, 106, https://doi.org/10.1029/2025EO250234. Published on 26 June 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.

Every summer, typhoons threatening the Korean Peninsula draw their energy from the warm waters of the Northwest Pacific Ocean. In recent years, the frequency and intensity of extreme weather events—such as heat waves, droughts, and heavy rains—have been increasingly linked to rising sea surface temperatures (SST).

Author(s): Ting-yu Yao, Ji-xu Gao, Miao Tian, Shun-xin Zhang, Fu-cheng Liu, Bao-quan Ai, Yan Feng, and Ya-feng He

It is demonstrated experimentally that the effective separation of bidispersed microspheres (dust particles) in the underdamped and strongly coupled regime is realized using a designed dusty plasma ratchet. Experimental findings reveal that these dust particles can undergo directional transport at v…

[Phys. Rev. E 111, 065216] Published Thu Jun 26, 2025

A major landslide has occurred in the vicinity of Altos de Oriente and Manantiales, near to Medellín and Bello, in Colombia. It is believed that about 25 people died.

On 24 June 2025 at 3:20 am, a large landslide occurred in the vicinity of Altos de Oriente and Manantiales, near to Granizal in Colombia. At the time of writing, 13 bodies have been recovered and a further 12 are missing. In total, 50 houses were destroyed.

I don’t yet have the precise location of this landslide tied down. A map on the El Colombiano news site places it at [6.30905, -75.53277], but this is yet to be confirmed.

There is very good aerial footage of it in a news report posted to Youtube by Cubrinet:-

At around 1 minute 45 seconds into this footage, this image is captured-

The 25 June 2025 landslide at Granizal in Colombia. Still from a video posted to Youtube by Cubrinet.

This image shows the crown of the landslide:-

The crown of the 25 June 2025 landslide at Granizal in Colombia. Still from a video posted to Youtube by Cubrinet.

The failure has occurred in deeply weathered regolith. It is a debris slide, with the main portion being comparatively deep-seated. It is notable that there is a considerable volume of water visible in the images:-

The upper portion of the 25 June 2025 landslide at Granizal in Colombia. Still from a video posted to Youtube by Cubrinet.

Some news sites note that a water pipe has ruptured in the landslide. The failure occurred during a period of very heavy rainfall – the El Colombiano site quotes a local resident as saying:-

“It was raining all day and all night. About 10:00 p.m. there was a downpour that cleared before 2:00 a.m. When it wasn’t even raining, we heard the noise and when we found out, we realized that the mountain had come and covered the entire neighborhood”.

Sometimes, a small failure associated with heavy rainfall can rupture a water pipe, which feeds water into the slope, triggering a much larger landslide.

Low down in the track of the landslide, it has spread and bifurcated, controlled by the topography:-

The main body of the 25 June 2025 landslide at Granizal in Colombia. Still from a video posted to Youtube by Cubrinet.

Thee are concerns about a further landslide at this site, imperiling the teams charged with recovering the victims.

Return to The Landslide Blog homepage Text © 2023. 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.

AbstractIn recent years, offshore tsunami observation networks equipped with ocean bottom pressure gauges (OBPGs), such as S-net, DONET, and N-net, have been deployed around Japan, enabling real-time collection of high-quality tsunami data near the source. These networks make it possible to estimate the spatiotemporal variation of the tsunami wavefield using a data assimilation approach, and to predict coastal tsunamis from the initial or current tsunami wavefield. This study proposes a novel tsunami data assimilation method that uses physics-informed neural networks (PINNs) to estimate tsunami wavefields from the observed OBPG data. The neural network was optimised by minimising the sum of the data loss, which quantifies discrepancies from the tsunami data, and the physical loss, which quantifies the satisfaction of the linear long wave equation. This was performed to ensure that the estimated results are consistent with both the observed data and the physics of tsunami propagation, even when there are limited observational data and significant noise. We first validated the effectiveness of the proposed method using synthetic S-net OBPG data from the 2011 Tohoku-oki earthquake (Mw 9.0) tsunami. The results confirmed that by using both data and physical constraints in the PINN optimisation, the PINN could adequately assimilate the spatiotemporal distribution of the tsunami wavefield from OBPG data, even for predictions outside the network coverage area. The predicted tsunami waveforms at the coastal stations, computed from the estimated initial wavefield, showed good agreement with the actual waveforms. Next, we conducted an experiment using actual S-net OBPG data from the 2016 Fukushima-oki earthquake (Mw 6.9) tsunami. The initial tsunami source estimated by PINN was in good agreement with other studies based on waveform inversion, although the maximum source amplitude and maximum coastal tsunami heights were underestimated. We also conducted an experiment using N-net OBPG data from the 2024 Hyuganada earthquake (Mw 7.0) tsunami. The PINN could accurately estimate the initial tsunami source, even though the tsunami source of this event was located outside the N-net coverage area. Finally, we have shown that incorporating tsunami observations over time into the iterative optimisation of the PINN model allows for accurate and efficient tsunami data assimilation.

AbstractUnderstanding processes in the Critical Zone requires reliable information about the vadose-zone aquifer, its geometry, and spatial variability. Commonly, such information is obtained from boreholes, yet large areas might render their application prohibitively expensive. Additionally, limited geological a-priori information might bias the interpretation due to lateral geological changes smaller than the borehole sampling scale. The transient electromagnetic method (TEM) has emerged in the last decades as a well-suited method to efficiently investigate the subsurface, as required for many hydrogeological applications. The interpretation of TEM measurements relies mainly on deterministic inversions, offering only a limited insight on the uncertainty of the subsurface model. Uncertainty quantification, however, is essential for integrating TEM results into hydrogeological models. Hence, we propose a combined approach using both deterministic and stochastic inversion of TEM soundings to investigate the uncertainty of shallow (< 40 m) aquifers. Current stochastic approaches for TEM data rely on Markov chain Monte Carlo algorithms, which have to be run from scratch for each individual sounding. Alternatively, machine learning approaches, such as Bayesian Evidential Learning (BEL), can be much faster because they do not require retraining for every new data set. Hence, we investigate, in particular, the application of a single, common prior model space instead of multiple, individual prior model spaces to directly estimate the uncertainty of multiple TEM soundings. To this end, we combine forward modelling routines with the stochastic inversion approach BEL1D and assess our approach using both field data and numerical experiments.

SUMMARYThe Fennoscandian earthquake catalogue (FENCAT) assembles data on the natural seismicity in Fennoscandia, Northern Europe. We present an updated and standardized version of the catalogue originally published in the early 1990s. New instrumental data are recorded by the seismic networks of Denmark, Estonia, Finland, Norway, and Sweden, and analyzed by the Geological Survey of Denmark and Greenland, the Geological Survey of Estonia, the University of Helsinki in Finland, the University of Bergen and the NORSAR research foundation in Norway, and Uppsala University in Sweden. The updated catalogue provides the available earthquake parameters in a brief, user-friendly version: origin time, source coordinates, focal depth, macroseismic data (maximum intensity and radius of the area of perceptibility), up to three observed magnitudes, seismic moment estimate, and a standardized moment-related magnitude, mW(HEL), for each event. The standardized magnitude is defined in this paper and its relation to other magnitude scales is provided. Suspected non-earthquakes (e.g. frost events, explosions, human-induced events) have been removed. The standardized event magnitudes range from mW(HEL) -1.0 to 6.2. To enable the usage of earthquake data in a large variety of seismological, geological and earthquake engineering investigations, the data are not truncated at the low magnitude end.The updated catalogue, FENCAT (2021), contains about 23 000 earthquakes for the period 1467–2021 in an area bounded by 54–75°N latitudes and 0–45°E longitudes. The completeness and quality of the earthquake solutions is best within the areal coverage of the above-mentioned networks.

AbstractWhile modern thermal convection in rocky planets is controlled by a slow solid-state creep flow, the earliest stages of terrestrial planets likely experienced turbulent flow during which their silicate envelope was fully molten, usually called magma ocean. The main parameter separating the two regimes is the Prandtl number (Pr), which is so high for mantle convection to be usually assumed infinite, whereas magma oceans are characterized by Pr on the order of 1. We compared the results of isoviscous convection simulations performed with three codes: (GAIA, TLBM, StreamV). These codes are based on different numerical formulations and were used for modeling convection with Pr ranging from 1 to 1000, while exploring different convection intensity by varying the Rayleigh number (Ra) from 104 to 106. GAIA (Generic Automaton for planetary Interior Analysis) is a Finite Volume fluid flow and energy solver for the Navier-Stokes equations across arbitrary geometries. TLBM (Thermal Lattice Boltzmann Method) solves the mesocale momentum and energy distribution densities for colliding particles on a discrete lattice. StreamV is a Eulerian-Lagrangian Finite Volume code that solves the Navier-Stokes equations under the Boussinesq approximation. The codes are compared over 24 different simulation setups, analogue to the classical Blankenbach infinite Pr benchmark (Blankenbach et al., 1989a), but extending it to finite Pr and to two types of boundary conditions, free-slip and no-slip. We show that the results of the three codes are generally in good agreement, and discuss differences. Finite Pr solutions show a much richer dynamics varying from stable steady-state solutions, to oscillatory and chaotic ones, and converging to infinite Prandtl number solution for increasing values of Pr for larger Ra: Pr ≥ 100 is sufficient for Ra = 105 but Pr ≥ 1000 is required for Ra = 106. Our results offer a robust set of solutions useful for testing future finite Prandtl number convection codes.

SUMMARYOur viewpoint highlights the challenges faced by women in the Induced Polarization (IP) community (and elsewhere), particularly the persistent gender imbalance in scientific workshops. This underrepresentation in leadership roles, presentations, and discussions reflects broader systemic biases in academia. By sharing the experience of the 7th IP workshop, where the organizing team made deliberate efforts to prioritize gender and diversity in organizing committees, recruitment, and session formats, we demonstrate how intentional actions can create a more inclusive, gender-balanced environment. This approach is crucial not only for the IP community but for all research communities. Emphasizing diversity and inclusion fosters a welcoming atmosphere that encourages participation from all individuals, regardless their background. In turn, this enriches the research process by incorporating diverse perspectives, driving innovation, and improving scientific outcomes. We aim to inspire other academic communities to actively promote diversity and inclusivity, recognizing that such efforts not only benefit underrepresented groups but elevate the success and relevance of science as a whole.

Taking carbon out of the atmosphere is essential for slowing global warming—and a team of Cornell University researchers has estimated "huge" potential for carbon capture using a method that is low-tech, sustainable and relatively simple: burying wood, especially the debris from managed forests.

A recent study by The Hong Kong University of Science and Technology (HKUST) reveals a looming climate crisis: the world could face heightened risks of "precipitation whiplashes"—violent swings between extreme droughts and floods—as early as 2028.

body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

Staff at the National Science Foundation (NSF) were notified on 25 June that the agency’s office space, located in Alexandria, Va., will be taken over by Department of Housing and Urban Development (HUD) staff, raising the question of where more than 1,800 NSF employees will work. 

One NSF employee told E&E News that they had “literally zero idea” the news was coming until word spread among staff the previous evening. Many NSF employees had relocated to Northern Virginia on short notice when return-to-work orders were issued in January. NSF only moved into the newly constructed building in 2017 from its prior location in Arlington, Va.

In front of a banner reading “The New Golden Age of HUD” at a 25 June press conference, HUD Secretary Scott Turner announced that a “staggered and thoughtful” relocation process would take place. The relocation will move forward “as quickly as possible,” Michael Peters, commissioner of the Public Buildings Service for the U.S. General Services Administration, said at the press conference.

On 24 June, Jesus Soriano, president of the American Federation of Government Employees (AGFE) Local 3403, a union representing NSF staff, sent an alert to union members informing them that “HUD will take over the NSF building” and that NSF had not been involved in the decision, according to E&E News.

Speakers at the press conference did not provide details about HUD’s plans for the space. In a statement, AGFE Local 3403 indicated that the union was told that plans would include an executive suite for Turner, the construction of a new executive dining room, exclusive use of one elevator for Turner, and a gym for Turner and his family.

 
Related

•  Press Conference: The New Golden Age of HUD
•  American Federation of Government Employees Local 3403 Statement
•  Science Agency Staff Brace for HQ Takeover
•  Get Involved: AGU Science Policy Action Center
 

“While Secretary Turner and his staff are busy enjoying private dining and a custom gym, NSF employees are being displaced with no plan, no communication, and no respect,” AGFE Local 3403 wrote in the statement.

Turner rebuked the idea that the move was about personal perks. “This is not about Scott Turner. I didn’t come to government to get nice things,” Turner said. “This is about the HUD employees.”

Turner added that unsafe working conditions at the current HUD office space in Washington, D.C. were the reason for the move. “I would hope that no leader in government or otherwise would expect staff to work in an atmosphere where the air quality is questionable, leaks are nearly unstoppable, and the HVAC is almost unworkable. It’s time for a change.”

Addressing the coming transition for NSF, Peters said, “We are going to continue to support the National Science Foundation as we support every agency across the federal government to identify space that allows them to continue to fulfill their mission.” 

In its statement, AGFE Local 3403 pointedly questioned the merit of the relocation plan: “At a time when they claim to be cutting government waste, it is unbelievable that government funding is being redirected to build a palace-like office for the Secretary of Housing and Urban Development. The hypocrisy is truly dumbfounding.”

—Grace van Deelen (@gvd.bsky.social), Staff Writer

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. 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.