EOS

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Advances in Modeling Earth Systems

What determines whether a cloud produces rain? This question has been challenging atmospheric scientists for decades due to difficulties in validation with real-world observations alone.

Chen et al. [2025] used the Pi Cloud Chamber at Michigan Technological University to provide steady, repeatable laboratory measurements for a range of aerosol injection rates. The scientists tested high-resolution numerical models of varying complexity, from a one-dimensional turbulence model to 3D large-eddy-simulations. Each model simulated how rapidly injected aerosols activate into droplets, grow, and fall out within the turbulent, moist chamber.

All models exhibited similar trends in droplet number concentration and mean droplet size in response to variations in the aerosol injection rates, but the exact values for a given injection rate differed greatly. These differences arose from how models represented processes such as droplet formation, particle loss through chamber’s bottom and sidewalls, near-wall moisture exchange, and turbulence properties. Despite these disparities, the models agreed on key scaling relationships between aerosol injection rates and droplet properties, consistent with both chamber measurements and theory.

The results highlight the unique value of laboratory facilities for benchmarking and improving cloud microphysics in models and point to priorities for future work to better constrain models and reduce uncertainty. More broadly, this first-of-its-kind model intercomparison demonstrates how laboratory measurements can inform and improve model representation of cloud-aerosol interactions.

Citation: Chen, S., Krueger, S. K., Dziekan, P., Enokido, K., MacMillan, T., Richter, D., et al. (2025). A model intercomparison study of aerosol-cloud-turbulence interactions in a cloud chamber: 1. Model results. Journal of Advances in Modeling Earth Systems, 17, e2024MS004562. https://doi.org/10.1029/2024MS004562

—Jiwen Fan, Editor, JAMES

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: Global Biogeochemical Cycles

Throughout the first half of 2020, average monthly temperatures in Siberia reached 6°C above the norm. The situation climaxed on 20 June, when the temperature in the town of Verkhoyansk climbed to 38°C (100.4°F), the highest temperature ever recorded north of the Arctic Circle. With the extreme heat came wildfires, insect outbreaks, and thawing permafrost.

Now Kwon et al. suggest that the effects of the 2020 heat wave were still detectable the following year in the form of warmer- and wetter-than-usual soils.

The researchers obtained data on temperatures, precipitation, and other climatic factors from the European Centre for Medium-Range Weather Forecasts and incorporated them into a model of high-latitude ecosystems. To capture the effect of the 2020 Siberian heat wave, they replaced data from 2020 with data from each of the previous 5 years (2015 to 2019), which provided five estimates of what regional ecosystems might have looked like in 2021 had the heat wave not occurred.

The analysis indicated that the high heat caused soil temperature to remain roughly 1.2°C, or about 150%, warmer in 2021 than it would have been without the heat wave, even though air temperatures had returned to normal. The warmer temperatures also melted soil ice, resulting in wetter soil than usual. Root zone soil water availability, a measure of how much water soil can hold in the rooting depth of plants, increased by 10.9% in forests in 2021 and by 9.3% in grasslands. However, some of this meltwater left the soil via runoff.

In response to warmer, wetter soil, microbes proliferated and caused the soil ecosystem to emit more carbon dioxide than usual, the modeling indicated. In forests, this effect was largely offset by an increase in photosynthesis as plants flourished under the new conditions. In grasslands, on the other hand, photosynthesis initially increased during the heat wave event but then quickly decreased until 2021 as plants used up the available water and died off. As a result of the 2020 heat wave, the researchers reported, forests gained an additional 6 grams of carbon per square meter in the first half of 2021, whereas grasslands lost 10.9 grams of carbon per square meter. (Global Biogeochemical Cycles, https://doi.org/10.1029/2025GB008607, 2025)

—Saima May Sidik (@saimamay.bsky.social), Science Writer

Citation: Sidik, S. M. (2025), In the Arctic, consequences of heat waves linger, Eos, 106, https://doi.org/10.1029/2025EO250313. Published on 22 August 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.

It took only 1.3 seconds for the Sagaing Fault to open a gash in Earth’s surface and shift it by 2.5 meters during the magnitude 7.7 Myanmar earthquake earlier this year. When video surveillance some 120 kilometers south of the earthquake’s epicenter caught the moment, the footage sent a shock wave of excitement through the global seismology community.

At first, Jesse Kearse, a geophysicist at Kyoto University, was simply in awe of the tectonic forces, but as he rewatched the video, he soon realized its scientific value. “Of all the instrument records we have of earthquakes from the past 100 years, most are from far away,” he said. This was the first real-time observation of a major rupture close to a fault.

Kearse and Yoshihiro Kaneko analyzed the video frame by frame using a technique called pixel cross correlation. Their findings, published in The Seismic Record, revealed the pulse-like nature of major earthquake propagation and the curvature of fault slip.

How Earthquakes Move Along a Fault

Seismologists have long understood that a fault doesn’t rupture all at once. Instead, it experiences a traveling, localized zone of slip, said David Wald, a geophysicist at the U.S. Geological Survey in Golden, Colo., who was not involved in the new research.

Wald’s work on the 1992 magnitude 7.2 Landers earthquake in California helped to establish that earthquakes propagate in pulses. But this work was “always a step removed from reality, modeling the rupture propagation process” as opposed to watching it in real time, he said.

“Seeing is believing.”

“Seeing is believing,” Wald said of the Myanmar footage. “We were all blown away by the video, which confirms how a short slip duration, large slip, and thus high slip velocity produce a large pulse of ground shaking.”

Analysis of the Myanmar earthquake video showed that the traveling slip zone was only several kilometers wide, even though the earthquake ultimately ruptured a more than 400-kilometer-long section of the fault. Pulse-like rupture is a more efficient way to move Earth’s massive crust, Kaneko noted. “This video provides the first visual confirmation of it occurring in real time.”

Although crumpled landscapes left by earthquakes have shown that seismic ruptures can cause permanent offsets of many meters, until now it wasn’t clear whether that movement happens within 1 or 2 seconds. “The historic record shows the offset but not how quickly that happened,” Kearse said. “It’s becoming clear that these pulse-like ground motions are really large amplitude, meters per second of ground velocity. For large buildings, that’s very difficult to engineer for.”

Curved Slip Movement along the Kekerengu Fault, which ruptured during the 2016 Kaikōura earthquake in New Zealand, left slickenlines on the wall of an outcrop. Credit: Kate Clark, Earth Sciences New Zealand

The video analysis was challenging because ground shaking caused the camera to tilt and wobble. But Kearse and Kaneko managed to isolate the fault motion by systematically analyzing stationary targets in the footage. To their surprise, they watched the slip curve before it settled into horizontal motion.

Geologists know that earthquakes leave curved scratch marks known as slickenlines on fault surfaces. In a previous study, Kearse and his colleagues described these grooves on exposed surfaces of the Kekerengu Fault, one of several that ruptured in New Zealand’s 2016 magnitude 7.8 Kaikōura earthquake. When they fed those data into a model, the team found a link between the curvature of slickenlines and the direction that a fault ruptured.

The analysis of the Myanmar earthquake footage delivered real-time evidence of this connection between slip curve and rupture direction. “What our new study contributes is a quantitative analysis of both the speed and direction of the curved slip while the rupture is actively unfolding,” Kaneko said.

The research “fortifies the slickenline story.”

The research “fortifies the slickenline story” and may help seismologists better anticipate the ground shaking likely to occur in future events, said John Vidale, an Earth scientist at the University of Southern California. This understanding is particularly important for faults with the potential to rupture in massive earthquakes, including California’s San Andreas Fault and New Zealand’s Alpine Fault. Such earthquakes would affect major population centers differently, depending on the direction in which the earthquake traveled.

The Myanmar video also highlights the potential of autonomous cameras as tools in seismology, according to Haiyang Kehoe, an Earth scientist who will be joining the University of Oregon in December. “The proliferation of home security systems and traffic cameras increases the likelihood that some portions of future earthquake ruptures will be recorded with a similar amount of clarity.”

For Laura Wallace, a geodetic scientist at the University of Texas and the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, the work opens new potential for using slickenlines from paleoearthquakes to investigate whether a particular fault has a tendency to rupture in one direction or another. “Such insights would provide important information for future seismic hazard forecasts.”

—Veronika Meduna (@veronikameduna.bsky.social), Science Writer

Citation: Meduna, V. (2025), Video shows pulsing and curving fault behavior, Eos, 106, https://doi.org/10.1029/2025EO250307. Published on 21 August 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.

Editors’ Vox is a blog from AGU’s Publications Department.

Stemflow, or the flow of water along the surface of a plant’s stem, has been a subject of inquiry in forest hydrology since the latter half of the 1800s given its relevance to water balance studies. The consequences of stemflow to ecological and soil biogeochemical processes led to an influx of research in subsequent years.

Today, stemflow is a burgeoning research area for diverse groups of people because it sits at the nexus of the geosphere, atmosphere, and hydrosphere. Recent interest in the topic stems from an engineering and urban planning perspective as, despite its long history of study, research has not focused on the physics of how water moves down the stem and what forces control these actions.

A new article in Reviews of Geophysics takes the first step in exploring and defining the hydrodynamics of stemflow. Here, we asked the authors to give an overview of stemflow hydrodynamics, how scientists have applied established theory in new ways to explore this broadening field, and potential future research directions.

In simple terms, what is stemflow?

Stemflow is the aboveground flow of water along the exterior surface of a plant stem.

Stemflow is the aboveground flow of water along the exterior surface of a plant stem. It is initiated after precipitation intercepted by leaves and branches drains from outlying parts of the plant crown down the stem/trunk to the soil surface around the plant base. Unlike raindrops that pass unhindered through a plant canopy or penetrate it by dripping or splashing from vegetative surfaces (known as throughfall), stemflow experiences longer contact time with the surface of the stem.

On trees, this lengthened exposure of stemflow-bark interactions enables higher nutrient leaching and subsequent delivery of concentrated nutrients and water to roots. The funneling of enriched waters to the tree base is the primary reason that stemflow is a main contributor to what is termed ‘hot spots’ and ‘hot moments’ in biogeochemical cycling of near-trunk soils. This indicates that the input of water, solutes, particulates, and other matter are uneven in space and time with soils near tree trunks representing an area of disproportionately high rates of biogeochemical cycling.

What role does stemflow play in the broader environment?

Stemflow connects the atmosphere, biosphere, and geosphere. It links the canopy of a tree to the soil and acts as a pathway that delivers water and the substances it carries down the trunk to the ground. Along this path, water interacts with the bark and the organisms living on or within it, including fungi, bacteria, lichens, mosses, metazoans, and insects. For these reasons, stemflow has been traditionally studied in forest hydrology and forest ecology circles, but there is now elevated interest within the engineering and urban planning communities to quantify it.

For example, with respect to pollutant cycling, stemflow can account for some differences in the spatial patterning of radiocesium, a radioactive form of the element cesium, in near-trunk soils. In urban planning and stormwater design, for instance, stemflow could exacerbate stormwater runoff in areas without favorable soil conditions (i.e., paved areas, areas with compacted soils) where water could infiltrate. The role of trees in meeting different ecosystem services within broader green infrastructure plans is still being explored.

(a) Fluid movement on an inclined smooth plane showing how an initially uniform advancing front breaks down into zones of fast-moving regions (or fingering). The goal of hydrodynamics is to predict the conditions that lead to such instabilities based on force imbalances (here between gravitational effects and surface tension). (b) Similar network features to panel (a) of connected instabilities along a vertical concrete wall in a parking garage after a rainfall event. (c) Preferential paths of water movement along a vertical stem. (d) Water bubbling due to leaching of solutes as water moves along the stem. Such bubbling impacts how water properties (viscosity, surface tension, density) and the forces that depend on them are formulated. (e) The physics of water movement inside the stem (xylem and phloem) has been uncovered well before stemflow despite the fact that stemflow can be observed by the naked eye and its observation commenced well before those associated with the xylem and phloem. The complexity of the physics required for describing water movement along the exterior surface of the plant is one of the main reasons for this ‘knowledge lag.’ Credit: Katul et al. [2025], Figure 1

How do scientists observe and measure stemflow?

The first stemflow measurements were conducted by Karl Eduard Ney in 1870.  Later, in 1881, W. Riegler established a link between the arrangement of branches and leaves and the amount of water flowing down the tree trunk. Riegler’s work paved the way to a line of inquiry common in ecology: exploring relations between structure (in this case tree architecture, bark properties, etc.) and function (amount and chemical composition of water in stemflow, sustenance of life dwelling on bark surfaces, etc.).

Measuring stemflow is based on capturing the volume of water that flows down a tree stem or trunk during and after a rainfall event.

Measuring stemflow is based on capturing the volume of water that flows down a tree stem or trunk during and after a rainfall event. The water capturing mechanism involves attaching collars or gutters around the tree trunk. These capturing mechanisms direct water into a nearby collection system. The collection system is usually formed by a container or containers where changes in water volume within the container can be measured over time, which allows the calculations of flow rates and relate them to rainfall data.

The instrumentation used to record the changes in volume of water with time varies in time scale. Tipping-bucket gages and containers with automated pressure recording devices as well as optical methods have all been employed in field studies to track the volume of water changes in time. These devices enable determination of stemflow on time scales of a few minutes to multiple years. Stemflow measurements are certainly an area that can benefit from rapid advancements in instrumentation and dedicated facilities. Stemflow hydrodynamics, once completed, may also enable ‘in-silico’ (or computer modeling) studies addressing relations between ‘structure’ and ‘function.’

What is stemflow hydrodynamics?

Hydrodynamics is a branch of fluid mechanics concerned with the motion of fluids (especially water) and the forces acting upon them. The other key branch of fluid mechanics is hydrostatics, which deals with forces acting on fluids when the fluid is at rest (as may be the case for water behind a dam). Stemflow hydrodynamics is a subset of hydrodynamics that seeks to explore fundamental connections between water depth, velocity, and flow rates on stems in relation to the governing forces.

Stemflow hydrodynamics deals with three conservation laws: water mass (left), scalar mass (middle), and momentum (right). These conservation laws consider a small element repeated across the three panels featuring each conservation law.  For the conservation of mass, there is a certain mass per unit area (perpendicular to the flow direction) per unit time (known as flux) that enters and leaves (indicated by qin and qout), and the bark itself absorbs water (indicated by a sink Sw). The imbalance between these fluxes and sinks impacts the water depth (h) variation along the stem and in time as well as the velocity. The middle and right panels repeat such balances for scalars (where Sc represents leaching) and forces (wall friction, gravitational force and surface tension at the contact line between the waterfront, the atmosphere, and the bark surface). Credit: Katul et al. [2025], Figure 3

At any point on the stem where water flows, these forces are primarily classified as body forces (gravitational), surface forces (friction), and line forces (surface tension). Any imbalance between these forces cause water to accelerate when the driving forces (gravity) exceed the resistive forces or to decelerate when resistive forces exceed the driving forces. Describing the resulting flow rate and the forces acting on water as it traverses the stem remains a daunting challenge to be confronted by stemflow hydrodynamics. The force imbalance and the resulting acceleration/deceleration is mathematically expressed as a conservation of momentum equation much like Newton’s second law that states the net force imbalance per mass determines the acceleration of a solid object having a fixed mass.  

What is thin film theory and how can it apply to stemflow hydrodynamics?

Thin film theory is a branch of fluid mechanics that describes the depth and velocity of a thin layer of fluid moving over a surface. Its name derives from certain approximations to the conservation laws of mass and linear momentum when the film’s thickness is much smaller than the length or width of the domain (e.g. trunk height). It was utilized to find approximate solutions for seemingly intractable engineering problems that were otherwise difficult to solve, such as coating processes in industry (e.g., paint, polymer films), lubrication layers between surfaces, mucus transport in lungs and airways, tear films on eyes, microfluidics and lab-on-a-chip devices, among others. The theory also has an extensive history and usage in hydraulics and hydrology where it is referred to as the shallow water equations.

These equations were originally proposed in the 19th century by Adhémar Jean Claude Barré de Saint-Venant. The significance of these equations cannot be overstated as Saint-Venant was one of the 72notable French scientists and engineers whose names are inscribed on the Eiffel Tower in Paris (France). In hydrology and hydraulics, the shallow water equations are routinely used to describe unsteady flow in streams and rivers, flood routing, flood waves following a dam break, overland flow on hillslopes, estuarine and tidal modeling, among others. All these flow types are based on the so-called small slope approximation and do not account for line forces or surface tension. Stemflow, however, occurs on almost vertical stems and therefore does not satisfy the small slope approximation. Moreover, surface tension can play a role in the force balance as water traverses the stem. These factors may have played a role in why the Saint-Venant equations were overlooked in the study of stemflow.

What are the major unsolved or unresolved questions and where are additional research, data, or modeling efforts needed? 

There are numerous challenges that need to be addressed before a complete description of the governing equations of stemflow hydrodynamics can be declared. These challenges begin by expressing frictional and line forces as a function of velocity and depth, as well as formulating water losses to the bark interior as water travels across its surface. Below is a partial list of just three unresolved issues related to forces characterization and their connection to the local bark properties: 

Fluid Properties: The addition of surfactants due to plant residue (e.g., acids), dust particles (e.g., salt), or exuded sap (e.g., resin) can create foam or soap‐like flow to occur along the stem. These surfactants can alter water properties such as viscosity and surface tension in ways that await exploration. They can also introduce spatial gradients in interfacial properties such as surface tension that may lead to unbalanced planar stresses at the air-water interface that induce motion within the film.

Surface Tension: Much of the thin film theories represent surface tension as a static balance of all forces along the contact line between the bark surface, the moving waterfront, and the ambient air. However, in the case of an accelerating or decelerating water movement, additional terms disrupt the force balance along the contact line due to unsteadiness, inertia, and friction. These effects have not been quantified for bark surfaces. Surface tension also plays a key role in controlling the spatiotemporal evolution of traveling waves on the falling water sheet. It will be a challenging task to understand the effect of capillary forces on such nonlinear waves that are traveling on complex, nonstandard, and multiscale geometries such as a tree bark.

Breakdown of Sheet Flow: Thin film theory treats water movement as a sheet. However, protrusions and cavities within the bark disrupt the sheet flow representation. There are instances where water piles up in fissures and cracks – and is then suddenly released (jetting) or drips out, to contribute to stemflow volume elsewhere on the bark surface. The breakdown of the sheet flow approximation and what physics becomes appropriate when this breakdown occurs is not settled.

Breakdown of sheet flow due to the imbalance between surface tension (holding the water in cavities along the bark) and the weight of water piling up in cavities (pushing the water out). When the pile up force (or weight) exceeds the holding force (surface tension), the water can ‘drip’ or ‘jet’ out of cavities. When it jets out of cavities, the jetting water column may still break down into droplets whose size is larger than the holding cavity size. Credit: Katul et al. [2025], Figure 6

—Gabriel G. Katul (gaby@duke.edu; 0000-0001-9768-3693), Duke University, USA; Bavand Keshavarz (0000-0002-1988-8500), Duke University, USA; Amirreza Meydani (0000-0002-7932-1477), University of Delaware, USA; and Delphis F. Levia (0000-0002-7443-6523), University of Delaware, USA

Editor’s Note: It is the policy of AGU Publications to invite the authors of articles published in Reviews of Geophysics to write a summary for Eos Editors’ Vox.

Citation: Katul, G. G., B. Keshavarz, A. Meydani, and D. F. Levia (2025), Waterworks on tree stems: the wonders of stemflow, Eos, 106, https://doi.org/10.1029/2025EO255027. Published on 21 August 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). 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.

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

Cold regions with mountainous terrain can host a multitude of landslide hazards, including rock-ice avalanches. These mass movements are particularly dangerous, as the presence of ice can amplify the potential for the flow to travel exceptional distances. A better understanding of rock-ice avalanche mobility necessitates consideration of how the flow interacts with the material (e.g., snow, ice, and rock) that is encountered as it travels downslope.

Peng et al. [2025] develop a unique suite of small-scale physical experiments that consider variations in the ice content of the initial gravel-ice flow mixture, the slope angle along which the flow travels, and the type of erodible material that the flow overrides. The authors find that the flows exhibit higher mobility when overriding snow and ice is present compared to gravel and that, regardless of the erodible material type that the flows override, higher flow erosion rates correspond to higher flow mobility. This study highlights that the entrainment of snow, ice, and rock can significantly affect the mobility of rock-ice avalanches and is likely an important mechanism to consider when developing frameworks for hazard assessment.

Citation: Peng, C., Li, X., Yuan, C., & Huang, Y. (2025). Insights into the dynamics of rock-ice avalanches from small-scale experiments with erodible beds. Journal of Geophysical Research: Earth Surface, 130, e2025JF008303. https://doi.org/10.1029/2025JF008303

—Matthew A. Thomas, Editor, JGR: Earth Surface

Text © 2025. The authors. CC BY-NC-ND 3.0
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Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: AGU Advances

The degree to which global warming will affect atmospheric dynamics and, therefore, extreme weather is still uncertain. Broadman et al. [2025] find a clever way to reconstruct the history of one dynamical pattern that occurs when the jet stream forms five peaks and troughs around the Northern Hemisphere (referred to as a wave5 pattern). When this pattern occurs and persists during May-June-July there is a higher likelihood of co-occurring compound climate events — for example combined heat and drought in the southeastern United States, China, and southern Europe, but wetter than normal in Northwest Canada and Spain.

The authors combine multiple lines of evidence, tree ring records, climate reanalyses and models, to reconstruct variations in the strength of the early summer wave5 pattern and extend them over the past millennium. They find decadal variations but no significant trends in the occurrence of wave5 related climate extremes. However, a demonstrated link between La Niña conditions the preceding winter could potentially help in predicting the potential in some regions for extreme weather the following summer.

Citation: Broadman, E., Kornhuber, K., Dorado-Liñán, I., Xu, G., & Trouet, V. (2025). A millennium of ENSO influence on jet stream driven summer climate extremes. AGU Advances, 6, e2024AV001621. https://doi.org/10.1029/2024AV001621

—Susan Trumbore, Editor, AGU Advances

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Source: Earth’s Future

Federal lands—which make up about 640 million acres, or 28%, of U.S. soil—are used for many purposes, including conservation, recreation, and extraction of resources such as coal. Greenhouse gas emissions are released throughout the life cycle of coal use, including during its mining, transport, and combustion.

Merrill et al. estimated the amount of coal production and coal-related greenhouse gas emissions from federal lands from 2024 to 2051. Specifically, they focused on emissions of carbon dioxide, methane, and nitrous oxide from 30 existing mines on federal lands (excluding Native American lands) in six states.

Active mines, and some abandoned mines, generate fugitive emissions, or unintended emission leaks, via venting and drainage. To calculate fugitive greenhouse gas emissions of underground mines, the team used average emissions data from the five most recent years available (2016–2020). The researchers calculated emissions from surface mines using a method developed by the U.S. EPA.

To estimate transportation-related emissions, they turned to resources such as power plant coal receipts and coal mine news releases to find information about how far and by what means coal was transported. The team used information about coal composition and mine characteristics, along with public reports, to estimate the most likely end uses of coal, such as cement production, conversion into coke (a fuel used in iron ore smelting and blacksmithing), or, most commonly, combustion.

From their analysis, the researchers estimated that between 2024 and 2051, coal production from federal lands will decline to 14.2% of 2023 production levels. The fastest rates of decline will occur between 2037 and 2048 because of the anticipated closure of a number of coal power plants. In the same time period, greenhouse gas emissions from coal mining on federal lands are projected to decrease 86% from 2024 estimates. Most of this reduction, roughly 95%, would come from reducing end point combustion of coal.

The team noted that their work was based on information that existed at the beginning of 2024 and that their findings are subject to possible changes in land management decisions. They suggest that these estimations can be helpful as part of domestic and global decisionmaking around greenhouse gas emissions and the future use of coal. (Earth’s Future, https://doi.org/10.1029/2024EF005735, 2025)

—Sarah Derouin (@sarahderouin.com), Science Writer

Citation: Derouin, S. (2025), By 2051, emissions from coal mining on federal lands could drop by 86%, Eos, 106, https://doi.org/10.1029/2025EO250305. Published on 20 August 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’ Vox is a blog from AGU’s Publications Department.

By the middle stage of a scientist’s career, expertise and reputation have been established, creating space to test out fresh opportunities and expand one’s comfort zone. For three scientists who wrote or edited books as mid-career researchers, this professional stage was very much a “happy medium.” They describe honing their research interests, gaining more autonomy to mold their work life, and finding joy in new roles within and beyond academia. Among these new undertakings was writing or editing a book. In the second installment of three articles, scientists contemplate why a book project was the perfect addition to the dynamic mid-career stage of their professional journeys.

Gaye Bayrakci coedited Noisy Oceans: Monitoring Seismic and Acoustic Signals in the Marine Environment, a comprehensive review of the sources and impacts of different types of marine noise. Bethany Hinga authored Earth’s Natural Hazards and Disasters, a textbook about the science behind natural events and how to prepare for disasters. Tamie Jovanelly authored Iceland: Tectonics, Volcanics, and Glacial Features, which explores the dramatic forces that have shaped the Icelandic landscape. We asked these researchers what developments shaped their mid-career stage, how a book fit in with their other goals and responsibilities, and to what extent their books influenced their next steps.

How would you describe the middle stage of a scientist’s career?

It’s a stage where you’re trusted with responsibility, but you also have the freedom to shape your role.

GB: Mid-career is genuinely exciting. I’m no longer dealing with early-career uncertainty, but I’m still actively thinking about what I want to focus on in the years ahead. It’s a stage where you’re trusted with responsibility, but you also have the freedom to shape your role, whether that’s through supervision, strategic planning, or external engagement. That sense of possibility is one of the best parts of this stage. It is also when you begin to think more about legacy, considering the kind of contribution you want to make in the long run, and that adds meaning and motivation to the work.

BH: I think for a lot of scientists this is the time when research programs and professional relationships are well cemented, and they have a growing bench of graduate students they’ve trained and are moving out into the world to do great things. My experience was different. Ten years post-PhD, I was in higher education administration and starting to branch out into other areas of expertise related to that administrative work.

Why did you decide to complete a book project? Why at that point in your career?

TJ: I decided to write a book after leading a field studies course in Iceland for over a decade. Throughout this time, I noticed a significant gap in the textbook market. While several publications touched on Iceland’s volcanology at a basic level, none provided a comprehensive overview of the island’s tectonics, volcanics, and glacial features. Recognizing this need, I felt compelled to contribute a resource that would serve both educators and students in the field of geology. My prior course preparation not only solidified my understanding of Iceland’s unique geological landscape but also allowed me to organize this knowledge effectively.

It was a chance to do something creative rooted in my scientific discipline.

BH: I had a twelve-month position in Academic Affairs at my university and the students and faculty were only on campus for nine months. I had three months of the year with time on my hands and a deep desire to start on a book that had been simmering in my head for years. I also had incredibly talented colleagues who were willing to write chapters in areas I felt were important to include in the book, but I didn’t have the expertise or comfort level to write myself. It was a chance to do something creative rooted in my scientific discipline, and it was a welcome change of gears from my job during the academic year, which had nothing to do with my discipline.

GB: The idea came when someone in my professional network, Frauke Klingelhoefer, was invited by AGU to propose a book on short-duration or non-earthquake seafloor signals. She contacted me, and we quickly realized that a broader book on ocean noise would be more valuable. It is a timely topic, relevant to biology, climate, defense, and offshore infrastructure, yet still underrepresented in the literature. Frauke, being very busy, suggested we co-edit and encouraged me to take the lead. It felt like the right moment to take on a creative, community-focused project.

What were some benefits of doing a book as a mid-career researcher?

It helped me see connections across disciplines and engage with researchers I might not have otherwise worked with.

GB: Editing the book gave me a much broader view of how scientists use pressure and sound to study both the water column and the shallow subsurface. It helped me see connections across disciplines and engage with researchers I might not have otherwise worked with. It was also a chance to step back, reflect on my own work, and rethink my scientific direction. I’ve since started new collaborations and found ways to apply similar techniques in my projects. The process confirmed that there’s still so much space to grow at mid-career.

TJ: Writing a book as a mid-career researcher offers several significant benefits. First, at this stage in my career, I had successfully navigated key responsibilities toward earning promotion and tenure. With these milestones behind me, I had the freedom to pursue projects that genuinely interested me making the writing process very enjoyable. Second, after years of publishing scientific journal articles, I had honed essential skills in conducting literature searches, synthesizing scientific arguments, and formulating key questions. These competencies not only streamline the writing process but also bolstered my confidence as an author. I felt capable of presenting complex ideas in a manner that is accessible to a broader audience. Third, writing a book allowed me to establish myself as a thought-leader in my field. By compiling my insights and research findings into a cohesive monograph, I have solidified my reputation as an expert on specific topics. This has led to greater visibility within the academic community, opened doors with new collaborators, and presented countless speaking engagements and other professional opportunities.

What advice would you give to mid-career researchers who are considering writing or editing a book?

Writing a book is an excellent way for a mid-career researcher to fall in love with science again.

TJ: My advice for any mid-career researcher considering writing a book is to realize that you are not an expert before you write the book; you are an expert after you write the book. Tackling a book project with this mentality automatically provides you with some grace when you are asking questions that you don’t yet have the answers to. Writing a book is an excellent way for a mid-career researcher to fall in love with science again, and it will make you a better classroom teacher and science communicator as a result.

BH: This is really the perfect time in your career to take on a project of this type!

—Gaye Bayrakci (g.bayrakci@noc.ac.uk, 0000-0003-1851-5021), National Oceanography Centre, UK; Bethany Hinga (Beth.Hinga@Newberry.edu, 0000-0003-0694-5331), Newberry College, USA; and Tamie Jovanelly (tamiejovanelly@gmail.com, 0000-0002-4374-0266), Adventure Geology Tours, USA

This post is the second in a set of three. Learn about leading a book project as an early-career researcher. Stay tuned for the third installment.

Citation: Bayrakci, G., B. Hinga, and T. Jovanelly (2025), Mid-career book publishing: bridging experience with discovery, Eos, 106, https://doi.org/10.1029/2025EO255026. Published on 20 August 2025. This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s). 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.

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

The prevailing view of mammal activity in ecosystems is that they have marginal impacts to services like greenhouse gas emissions. However, that is not always the case, especially with large, feral ungulates. In northern Australia, the indigenous Yolŋu peoples connect and rely on coastal wetlands for spiritual connection, tourism, fisheries, and crocodile egg harvesting. These wetlands, however, suffer damage from invasive pigs and buffalo. The Yirralka Rangers of the region attempt to control these from the air.

Crameri et al. [2025] partnered with the local community to evaluate the impact of these feral ungulates on wetland greenhouse gas emissions and carbon stocks, an ecosystem service growing in value for climate change mitigation. Fenced enclosures allowed the authors to reveal a fourfold increase in carbon dioxide and methane emissions in unfenced areas, while fenced areas increased in belowground biomass with limited impact on soil organic carbon. The work demonstrates how research partnerships with local communities, as documented in the article’s Inclusion in Global Research statement, can support local land stewardship and contribute to global conservation and climate mitigation efforts.

Citation: Crameri, N. J., Mununggurr, L., Rangers, Y., Gore, D. B., Ralph, T. J., Pearse, A. L., et al. (2025). Feral ungulate impacts on carbon cycling in a coastal floodplain wetland in tropical northern Australia. Journal of Geophysical Research: Biogeosciences, 130, e2025JG009056. https://doi.org/10.1029/2025JG009056

—Ankur Desai, Associate Editor, JGR: Biogeosciences

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.

Water ice molecules are among the most common in the cosmos and influence the interior and exterior of many planetary bodies in our solar system. Glaciers shape parts of Earth’s surface, and dwarf planet Pluto, along with moons such as Europa, Ganymede, Titan, and Enceladus, have whole landscapes made up of ice alone, including boulders, mountains, and even volcanoes.

Under high-pressure or very low temperature conditions, ice forms different crystal structures than those that occur naturally on Earth. Identifying and measuring those structures on worlds such as Ganymede would provide unique data on the interiors of these celestial bodies, in the same way studying mantle rocks pushed to the surface on Earth reveals our planet’s deep geology.

In the lab, researchers can bombard ice with X-rays or neutrons to understand its structure. But such instruments aren’t practical to fly on spacecraft.

“The ices that we prepare in the lab only occur naturally in space.”

Now, new experiments conducted by Christina Tonauer and her colleagues at Universität Innsbruck in Austria show how to distinguish between ice structures using infrared spectroscopy. The analyses, published in Physical Review Letters earlier this summer, can be done using observations from NASA’s James Webb Space Telescope (JWST) or the European Space Agency’s JUICE (Jupiter Icy Moons Explorer) mission currently en route to Jupiter.

“The ices that we prepare in the lab only occur naturally in space,” said Tonauer, whose work combines her field of physical chemistry with her love for planets. “I’m also really interested in astronomy, and this is what hooked me to water ice.”

During Tonauer’s Ph.D. work in the early 2020s, JWST was still to be launched, but it was clear the infrared observatory would open avenues for studying the ice-covered moons of the outer solar system. When she and her collaborators delved into the literature, they realized that a lot of spectroscopic work on ice—research that largely predated the leaps in understanding gained from the Voyager and Cassini missions—considered infrared (IR) wavelengths longer than those JWST could measure.

It seemed fruitful to Tonauer and her colleagues to study the shorter-wavelength IR spectrum (near-IR) emitted by ice on these distant worlds.

Ice Maker, Ice Maker, Make Me Some Ice

As of 2025, 21 different phases of ice have been identified in laboratory experiments, although only one form exists under normal conditions on Earth. That form is called ice Ih (pronounced “ice one aitch”), where “h” refers to the hexagonal pattern the molecule’s oxygen atoms take when viewed from one direction.

The conditions that allow researchers to study other ice phases in the lab exist naturally on other planets and moons, however, and scientists have concluded the phases might exist there.

Ganymede and other worlds in the outer solar system likely have something akin to mantle dynamics, for example, but with ice instead of silicate minerals.

Ganymede’s mantle could be 800 kilometers thick and consist of several forms of ice that are known only from laboratory experiments on Earth. Tonauer and her collaborators selected ice V and ice XIII for their study, because they form under the high pressures and low temperatures present inside Ganymede and other moons. These phases have the same arrangement of oxygen atoms, but different orientations of hydrogen atoms: In ice V, hydrogen is jumbled around, whereas hydrogen in ice XIII is structured.

Making these types of ice in the lab requires cooling liquid water with liquid nitrogen under about 5,000 atmospheres (500 megapascals) of pressure. As long as the samples are kept cold after forming, Tonauer noted, they don’t require high pressure to remain stable because the atoms move so slowly.

However, that slow motion still stretches the bonds between molecules, a vibration that produces IR signals. Using spectroscopy to interpret the emissions, Tonauer and her colleagues discovered that these signals are different for ice V and ice XIII. That difference provided the first experimental demonstration of using IR to distinguish hydrogen configurations within different phases of ice. It also highlighted a way to identify them remotely.

The researchers used a JWST simulator to show that a few hours of observation would be enough to distinguish between these ice phases on Ganymede.

A Peek at Deep Ice

The stability of these ice phases is key to understanding their potential presence on the surface of Ganymede: The phases require high pressure to form, but if brought to the lower-pressure surface, they can maintain their exotic crystal structure indefinitely. In that way, the presence of ice V or XIII would provide details about the icy mantle that would otherwise be inaccessible.

Past and present missions to the Jovian system have clearly indicated that Ganymede’s interior contains a liquid water ocean sandwiched between ice layers, but the ices’ crystalline structures, as well as how the layers move and evolve, have not been verified by empirical data. According to models of icy moon interiors, the high-pressure environment should produce ice V, which phenomena such as the tidal force from Jupiter might bring to the surface.

“We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return.”

These new infrared spectroscopy analyses show how to distinguish between ice Ih, ice V, and ice XIII—not to mention amorphous ice, which lacks a clear crystal structure—without having to return samples to Earth for laboratory analysis (a prohibitively expensive proposition). The method could provide an observational way to verify or refute models of interior ice dynamics, sharpen our picture of Ganymede’s internal structure, and help us understand how different flavors of ice behave and interact with each other in a natural environment.

“We can now potentially detect subtle structural differences on icy moons without needing a lander or sample return,” said Danna Qasim, a laboratory astrophysicist at the Southwest Research Institute in Texas who was not involved with the new study.

Qasim pointed out that if the grains of these ices are small and jumbled together, it might be difficult to extract their IR signature. As other recent research has shown, amorphous ice in space likely contains chunks of crystalline ice joined together at odd angles, which also might make identification more difficult.

However, the new method seems promising and could well answer vital questions about the internal structure of icy moons.

“We invest billions of dollars in these spectacular space missions,” Qasim said. “If we want to truly understand what the data is telling us about these enigmatic beautiful worlds, it is absolutely necessary to have laboratory experiments like the ones performed here.”

—Matthew R. Francis (@BowlerHatScience.org), Science Writer

Citation: Francis, M. R. (2025), Infrared instruments could spot exotic ice on other worlds, Eos, 106, https://doi.org/10.1029/2025EO250303. Published on 19 August 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.

This is an authorized translation of an Eos article. Esta es una traducción al español autorizada de un artículo de Eos.

No hace mucho, en un día de verano, 10 personas se reunieron para comer queso en nombre de la ciencia. Degustaron pequeñas porciones de Cantal, un queso firme de leche de vaca producido históricamente en el centro-sur de Francia, y evaluaron más de 25 atributos que incluyeron el color, el olor, el sabor, el aroma y la textura. La degustación era sólo uno de los componentes de un estudio más amplio sobre los efectos del cambio de la dieta de las vacas, del pasto al maíz, debido a la industrialización y el cambio climático. Los nuevos resultados subrayan la importancia de mantener al menos parte de la hierba en la dieta de las vacas. Los nuevos hallazgos resaltan la importancia de mantener al menos algo de pastos en la dieta de las vacas.

“Su fisiología y tracto digestivo están hechos para digerir pasto”.

Las vacas, con sus cuatro bolsas estomacales, están preparadas evolutivamente para consumir pastos y extraer todos los nutrientes posibles de ese forraje. “Las vacas son herbívoras”, afirma Elisa Manzocchi, investigadora láctea de Agroscope en Posieux (Suiza), que no participó en la investigación. (Agroscope es una organización gubernamental suiza dedicada a la investigación agrícola). “Su fisiología y tracto digestivo están hechos para digerir pasto”.

Pero en todo el mundo, los bovinos se alimentan cada vez más con un dieta basada en maíz a medida que prolifera la ganadería a escala industrial – a menudo es más fácil, más eficiente y escalable alimentar a las vacas con un comedero en lugar de permitirles forrajear en un pastizal.

El cambio climático también está impulsando este cambio. Incluso en regiones en las que por bastante tiempo han llevado a las vacas a pastizales verdes, los ganaderos se enfrentan a la escasez de pasto en verano debido a las sequías. Así ocurre en Marcenat, lugar donde se encuentra una granja experimental del Instituto Nacional de Investigación para la Agricultura, la Alimentación y el Medio Ambiente (INRAE), explicó Matthieu Bouchon, científico especializado en cría de animales de ahí. El verano hace más calor que antes, pero sigue lloviendo mucho en primavera, afirmó. “Las condiciones son perfectas para el cultivo de maíz”.

Ver campos de maíz en Marcenat, una región montañosa del centro-sur de Francia a una altitud de 1,000 metros, es desconcertante, dijo Bouchon. “No es algo a lo que estamos acostumbrados”.

Bouchon y sus colegas del INRAE, dirigidos por la microbióloga Céline Delbès, investigaron recientemente cómo la modificación de la dieta de las vacas tiene efectos secundarios en la cantidad, la calidad, el valor nutricional, y el sabor de su leche y el queso resultante. En trabajos anteriores se habían comparado los resultados de dietas a base de pasto y maíz, dijo Manzocchi, pero esta investigación es particularmente exhaustiva. “Es uno de los primeros estudios en los que se analizaron muchos parámetros”.

Del suelo al pasto, del pasto a la vaca, y de ahí a la leche y al queso

El equipo se centró en 40 vacas Prim’Holstein y Montbéliarde, dividiéndolas en dos grupos: uno alimentado con una dieta basada principalmente en pastos y otro con una dieta basada en el maíz con cierto acceso a pastar forraje. Después de dos meses, la mitad de las vacas del primer grupo comenzó a recibir una dieta con menos pasto, y a la mitad de las vacas del segundo grupo se les negó por completo el acceso al pasto. El resultado fue una cohorte de cuatro grupos de bovinos que, durante casi tres meses más, comieron aproximadamente un 75 %, 50 %, 25 % y 0 % de pasto, respectivamente.

A lo largo del experimento, Delbès y sus colaboradores recogieron muestras de leche dos veces por semana (las vacas se ordeñaban dos veces al día), muestras de suelo de los pastizales e incluso muestras de las ubres de las vacas. El objetivo era comprender mejor cómo un cambio en la dieta inducido por el cambio climático se traduce en cambios en los atributos de la leche de un rebaño y, en última instancia, en el queso. “Había muchas cosas en este experimento”, dijo Bouchon.

Los investigadores solicitaron la ayuda de una quesería cercana a la granja para producir pequeñas rondas de queso Cantal, de aproximadamente medio kilogramo cada uno, utilizando leche de las vacas de cada uno de los cuatro grupos. Los quesos se maduraron durante 9 semanas antes de ser servidos a un panel de catadores entrenados en la degustación de quesos tipo Cantal.

Conservar el pasto

En consonancia con hallazgos anteriores, los investigadores descubrieron que el queso elaborado con leche de vacas alimentadas principalmente con pastos era más sabroso y tenía niveles más altos de ciertos ácidos grasos en comparación con los quesos producidos a partir de vacas alimentadas principalmente con maíz. Sin embargo, las vacas alimentadas con dietas con una mayor proporción de pastos también producían menos leche en relación con la cantidad de alimento que consumían, señaló el equipo.

En general, Delbès y sus colaboradores descubrieron que el cambio de una dieta con un 25% de pasto forrajeado a una con un 0% de pasto forrajeado era más perjudicial para la calidad nutricional y sensorial del queso, que el cambio de una dieta con un 75% de pasto forrajeado a una dieta con un 50% de pasto forrajeado.

“Es sorprendente que sólo una cuarta parte de la dieta pueda [influir] tanto en la calidad sensorial del queso”.

El hallazgo sugiere que mantener al menos una mínima cantidad de hierba fresca es fundamental para garantizar la calidad del queso, afirmó Delbès.

“Es sorprendente que sólo una cuarta parte de la dieta pueda [influir] tanto en la calidad sensorial del queso”, dijo Manzocchi. Pero tal vez ese hallazgo debería tranquilizar a los productores de queso tradicionales que ya no pueden alimentar a sus rebaños con una dieta basada principalmente en pasto, agregó. “Quizás sea una buena noticia”.

Delbès y su equipo aún no han terminado con sus rebaños Prim’Holstein y Montbéliarde. El trabajo futuro se centrará en examinar cómo los microbios presentes en el suelo y las zonas de descanso de las vacas, por ejemplo, se correlacionan con los microbios presentes en el intestino humano después del consumo de queso.

—Katherine Kornei (@KatherineKornei), Escritora de ciencia

This translation by translator Stephanie Segura (@StephSeg_05) was made possible by a partnership with Planeteando y GeoLatinas. Esta traducción fue posible gracias a una asociación con Planeteando and GeoLatinas.

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.

Following the passage Typhoon Podul, the lake created by this massive landslide has now grown considerably. Overtopping is expected in October, although could occur sooner if further heavy rainfall occurs.

The landslide-dammed lake behind the the enormous 21 July 2025 rock avalanche in the Matia’an valley, in Wanrong township in eastern Taiwan continues to fill. Meanwhile, the landslide itself is evolving with time. This is a Planet Labs image of the site soon after the main rock avalanche occurred:-

Planet Labs image showing the site of the 21 July 2025 landslide in the Matia’an valley in Wanrong township, Taiwan. Satellite image copyright Planet Labs , used with permission. Image dated 25 July 2025.

Whilst this is the most recent satellite image (note that the right hand side is the older image):-

Recent Planet Labs image showing the site of the 21 July 2025 landslide in the Matia’an valley in Wanrong township, Taiwan. Satellite image copyright Planet Labs, used with permission. Image dated 18 August 2025.

And here is a slider so that you can compare the two images:-

Image copyright Planet Labs.

This area received very heavy rainfall as a result of the passage of Typhoon Podul. This has driven a number of changes. Perhaps most obviously, the lake is now very considerably larger. This will continue to grow over the coming weeks until overtopping occurs.

Second, as I noted in my original post, the landslide generated a large volume of dust which had settled around the deposit, especially to the south. This has now been washed away.

Thirdly, there have been more failures from the rear scarp of the landslide, so the landslide deposit has evolved.

And finally, the heavy rainfall has driven some erosion of the finer-grained portions of the landslide deposit.

It is also worth noting that a few other, smaller, lakes have now formed on the landslide. The largest of these is about 250 x 200 metres, so not insignificant.

On 14 August 2025, etaiwan.news posted an article in Mandarin about the landslide. It noted that the Taiwan Government has authorised funding to “develop disaster mitigation, monitoring, evacuation, and engineering plans”. This includes the development of an evacuation plan, but also “evaluation and planning, excavation of spillways, construction of embankments, bed consolidation, etc., to reduce the risk of dam collapse and protect downstream areas”.

The Hualien Branch of the Forestry and Conservation Department has released these two images of the lake at the site of the in the Matia’an valley:-

The deposit of the 21 July 2025 landslide in the Matai’an valley in Wanrong township, Taiwan. Image by provided by Hualien Branch of the Forestry and Conservation Department/Wang Zhiwei Hualien Fax.

The deposit of the landslide is well-captured, with the lake in the background. This is the same site from the lake looking towards the toe:-

The lake formed by the 21 July 2025 landslide in the Matai’an valley in Wanrong township, Taiwan. Image by provided by Hualien Branch of the Forestry and Conservation Department/Wang Zhiwei Hualien Fax.

Immediately after the typhoon, the lake had reached 43% of its storage capacity with a freeboard of 55 metres. Assuming that no further typhoons affect this area, and in the absence of the construction of a spillway, overtopping is likely to occur in October.

Reference

Planet Team 2025. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

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.

Source: Journal of Geophysical Research: Solid Earth

Around 1.1 billion years ago, the oldest and most tectonically stable part of North America—called Laurentia—was rapidly heading south toward the equator. Laurentia eventually slammed into Earth’s other landmasses during the Grenville orogeny to form the supercontinent Rodinia.

Laurentia’s path during that period is known, thanks to paleomagnetism. By tracing the orientation and magnetism of rocks in the lithosphere, scientists can approximate the relative position and movement of Laurentia leading up to Rodinia’s formation.

The rocks along Lake Superior in northern Wisconsin and Michigan are especially important for tracing Laurentia’s movement. These rocks—dominated by red sandstones, siltstones, and minor conglomerates—were deposited during extensive sedimentation caused by the North American Midcontinent Rift and are rife with iron oxides like hematite. Hematite can acquire magnetization when it is deposited, which records where the rock was in relation to Earth’s poles at the time.

Unfortunately, the existing paleomagnetic record is marred by a gap between 1,075 million and 900 million years ago, limiting our understanding of how, when, and where Rodinia formed.

To fill this data gap, Fuentes et al. collected new samples from the Freda Formation near Lake Superior, which formed in floodplain environments an estimated 1,045 million years ago. The authors combined these data with stratigraphic age modeling to estimate a new, sedimentary paleopole, or the position of the geomagnetic pole at a particular time in the past.

Previous studies indicate that for 30 million years, sometime between 1,110 million and 1,080 million years ago, Laurentia moved from about 60°N to 5°N at a rate of 30 centimeters (12 inches) per year—faster than the Indian plate’s collision with Eurasia pushing up the Himalayas. This study showed that over the following 30 million years, Laurentia’s progress slowed to 2.4 centimeters (1 inch) per year as it crossed the equator.

The paleocontinent’s slowdown during Freda Formation deposition coincides with the onset of the Grenville orogeny. The results confirm that a stagnant single-lid regime—in which the lithosphere behaves as a single, continuous plate rather than multiple independent plates—was not in effect during this interval. (Journal of Geophysical Research: Solid Earth, https://doi.org/10.1029/2025JB031794, 2025)

—Aaron Sidder, Science Writer

Citation: Sidder, A. (2025), Lakeside sandstones hold key to ancient continent’s movement, Eos, 106, https://doi.org/10.1029/2025EO250304. Published on 18 August 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: Tectonics

How do we detect past fault slip in slowly deforming regions like the Eastern Alps, where modern earthquakes are infrequent and geologic markers of seismicity are subtle or absent?

Prince et al. [2025] tackle this challenge using two innovative dating techniques: optically stimulated luminescence (OSL) and electron spin resonance (ESR). These “trapped charge” methods harness electrons that are caught in crystal defects or impurities in quartz or feldspar grains but can be released by stimuli such as light or heat. Here, the authors target quartz and feldspar in crushed fault rocks, or fault gouge. During an earthquake, work done to overcome the frictional strength of fault rocks is given off in the form of heat that may “reset” the OSL and ESR systems.

The authors compare ESR and OSL signals from fault gouges from three faults in the Eastern Alps: the Šoštanj, Periadriatic, and Lavanttal faults. They also quantify the ESR signal saturation, which gauges how close the trapped electron system is to its maximum capacity. Their results indicate that the Periadriatic and Šoštanj faults were active during the Quaternary period (the past about 2.6 million years). The Šoštanj fault shows evidence for the most recent activity, with OSL dates as young as about 30,000 years and low ESR saturation levels suggesting repeated signal resetting. In contrast, the Lavanttal fault gouge exhibits saturated ESR signals with dates ranging from about 860,000 to over 2 million years. These results imply the Lavanttal fault was seismically quiescent during the Quaternary, or the conditions of fault slip did not yield sufficient temperatures to reset the trapped charge systems.

This study spotlights the growing utility of trapped charge dating for documenting the slip histories of faults with or without historical seismicity. The analytical uncertainty of any trapped charge date (see figure above) far exceeds an individual or multiple earthquakes, and fault-slip temperatures at shallow depths can be insufficient to completely reset these systems, so it is challenging to fingerprint individual earthquakes with this approach. However, by harnessing the complementary strengths of OSL and ESR together with ESR saturation levels, the authors are able to reconstruct a fuller picture of the timing and distribution of shallow fault slip, which is critical for understanding regional tectonics and assessing seismic hazard.

Citation: Prince, E., Tsukamoto, S., Grützner, C., Bülhoff, M., & Ustaszewski, K. (2025).  Deciphering Pleistocene fault activity in the Eastern Alps: Dating fault gouges with electron spin resonance and optically stimulated luminescence. Tectonics, 44, e2024TC008662. https://doi.org/10.1029/2024TC008662

—Alexis Ault, Associate Editor, Tectonics

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.

At least 43 people were killed in devastating landslides and debris flows in northern China. Planet Labs images provide an insight into this disaster.

It is extremely challenging to keep up with the landslides occurring around the world at the moment. There has been a lot of attention paid to the remarkable rock slope failure and tsunami in Alaska. I feel that others are better placed to write about that (although I will probably continue to highlight updates via my BlueSky account), but if you get a chance please take a look at the images on the Alaska News Source website.

There have also been a devastating set of debris flows in northern Pakistan and parts of India and Nepal. At this stage, it is a little unclear to me as to the full extent of these events (especially in Pakistan) – I am likely to return to this theme.

Often the best way to understand an event is to piece together the news reports with satellite images when they become available. And so, let’s take a look at reported “floods” or “flash floods” (actually landslides and channelised debris flows) that occurred in Yuzhong County in Gansu Province in China on 7 August 2025. The BBC has a good report of the aftermath, whilst Al Jazeera reports 10 dead and 33 missing from this event. We must take reports of losses in China with a large pinch of salt.

The location of the source of this event is [35.71498, 104.02436]. So here is a Planet Labs image, dated 30 July 2025, showing the area affected. The marker is at the location highlighted above:-

Planet Labs image of the source of the 7 August 2025 landslides and debris flows in Yuzhong County, Gansu Province. Image copyright Planet Labs, used with permission. Image dated 30 July 2025.

And here is the same location after the event:-

Planet Labs image of the aftermath of the 7 August 2025 landslides and debris flows in Yuzhong County, Gansu Province. Image copyright Planet Labs, used with permission. Image dated 13 August 2025.

And here is a slider to allow you to compare the images:-

Images copyright Planet Labs.

This is a closer look at this area of intense landslides:-

Planet Labs image of the aftermath of the 7 August 2025 landslides and debris flows in Yuzhong County, Gansu Province. Image copyright Planet Labs, used with permission. Image dated 13 August 2025.

What we see here is literally hundreds of shallow failures that will have occurred almost simultaneously, and then combined to form devastating channelised debris flows. There are many failures on the slopes to the southwest, but the greatest concentration is to the northwest is an area that is densely vegetated.

This is indicative of extremely high rainfall intensities, but this storm was highly localised. The area of intense landslides is only about 9 km x 5 km.

The downstream impacts were terrible. These are the settlements immediately to the east of the landslides:-

Planet Labs image of the downstream area affected by the 7 August 2025 landslides and debris flows in Yuzhong County, Gansu Province. Image copyright Planet Labs, used with permission. Image dated 30 July 2025.

And here is the same area after the landslides:-

Planet Labs image of the downstream area affected by the 7 August 2025 landslides and debris flows in Yuzhong County, Gansu Province. Image copyright Planet Labs, used with permission. Image dated 13 August 2025.

And again, here is a slider to allow the images to be compared:-

Images copyright Planet Labs.

There is a large number of destroyed buildings in this imagery. The devastation extended for a considerable distance.

Reference

Planet Team 2025. Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. https://www.planet.com/

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.

Regions known as large low shear velocity provinces—more memorably known as “big lower-mantle basal structures,” or BLOBs—have long been known to seismologists because seismic waves generated by earthquakes slow down when they pass through them.

One BLOB is under Africa, and the other sits below the Pacific Ocean. They are thousands of kilometers wide and may be more than a thousand kilometers high, containing up to 8% of Earth’s total volume.

The origin of the BLOBs is not certain, nor is it clear what they are made of. Many researchers think the BLOBs formed from subducting oceanic crust at ancient plate boundaries, while another hypothesis suggests they are remnants of the asteroid impact that threw up the material that became the Moon.

BLOBs are hotter than the surrounding mantle and perhaps compositionally distinct. While some research predicts they are denser than the mantle rock that houses them, other models have found the opposite.

Plume Factories

In the early 2000s, a group of scientists led by Trond Torsvik of the University of Oslo suspected a link between the BLOBs and volcanic activity at Earth’s surface. To test this theory, they mapped the location of large igneous provinces (LIPs) and kimberlites—diamond-bearing volcanic rocks that originate deep in Earth’s interior. The researchers then rewound the clock on these emplacements, restoring them to their position on Earth’s surface when the eruptions occurred.

The results, published in 2006, revealed that most of the eruptions occurred at the edges of one of the BLOBs. These findings supported the idea that large mantle plumes at BLOB edges hurl heat energy toward the surface and create LIPs. Activity at LIPs can trigger supervolcanoes, rip supercontinents apart, and release vast amounts of greenhouse gases. LIPs have even been implicated in some of Earth’s major mass extinctions.

The neat fit between eruptions and the position of the BLOBs, researchers claimed, showed that the BLOBs were immobile; tectonic plates moved relative to them, but the BLOBS themselves stayed where they were.

Not So Fast…

Nicolas Flament, a geophysicist and geodynamicist with the University of Wollongong (UOW) in Australia, said the idea of fixed BLOBs was initially attractive to researchers because it promised to fill a knowledge gap in the paleomagnetic history of Earth.

Geologists trace the movement of tectonic plates using paleomagnetic evidence, written by Earth’s magnetic field on volcanic rocks as they cool and solidify. These data can reveal the latitudinal position of an eruption on Earth’s surface, but they cannot reveal anything about longitude.

“Everything moves.”

If BLOBs are fixed in one spot, Flament said, ancient eruptions could be linked to the edges of the BLOBs, providing a much-needed reference for paleolongitude.

As a geodynamicist, however, Flament inhabits a world where, he said, “everything moves.” The concept of fixed BLOBs didn’t sit well with him. In 2022, he and some colleagues ran models that rewound Earth’s clock back a billion years. These models showed that the position of volcanic materials at the surface could be explained just as well if the BLOBs moved.

Flament and his team contend that subducting slabs disrupt the BLOBs, and they regularly break apart and remeld just like continents do at the surface. But by Flament’s own admission, there is a weakness in these findings. Like the Torsvik-led research, it “assumed that there was a link between the BLOBs and the eruptions…We didn’t actually check” to confirm that the link was there.

Bridging the Gap

Now a team led by UOW Ph.D. student Annalise Cucchiaro that includes Flament has shown through statistical modeling that large volcanic eruptions are, indeed, connected to the BLOBs. The team mapped volcanic deposits against billion-year reconstructions of mantle movement. The research was published in Communications Earth and Environment.

The scientists found a significant link between volcanic deposits and the mantle plumes that models predicted, “essentially filling that gap,” Flament said.

The researchers found no significant relationship between mantle paths and the BLOB edges, however—mantle plumes could originate from anywhere on the BLOB, not just the edge. As plumes rise through Earth’s interior, they encounter “mantle wind”—lateral movement of semisolid rock that may cause the plumes to tilt by as much as 5° from vertical. This tilting, the research showed, could account for many of the volcanic eruptions that were not directly over a BLOB.

The research also suggested that the BLOBs are slightly denser and less viscous than the surrounding mantle. Rather than being completely static, the BLOBs likely move around at a rate of about 1 centimeter per year.

Qian Yuan, a geophysicist with Texas A&M University who was not involved in the study, called the findings “very reasonable.” Yuan was the author of the asteroid origin theory of BLOB formation.

“The subducting slab is the strongest driving force of the manual convection,” he said, “so in all our models, we show the BLOBs will move around.”

Big Bottoms

Fred Richards, a geodynamicist at Imperial College London who was not involved in the study, has researched BLOBs extensively, looking for a model that accommodates everything known about them from seismological and geophysical data.

The UOW research, he said, adds to a growing body of evidence that the lower parts of the BLOBs are dense, but not too dense to prevent them from moving around. Linking a dense, viscous base to the eruption record, he said, is “something that hasn’t been clearly shown before.”

—Bill Morris, Science Writer

Citation: Morris, B. (2025), Blame it on the BLOBs, Eos, 106, https://doi.org/10.1029/2025EO250302. Published on 15 August 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

Off the southern coast of Chile, three tectonic plates meet at a point known as the Chile Triple Junction. Two are oceanic plates, the Nazca and the Antarctic, which are separating in an active spreading center, creating a mid-ocean ridge between them. At the same time, both plates—spreading ridge included—are sliding into the mantle beneath a third plate, the South American. The Chile Triple Junction is the only place on Earth where an active spreading center is subducting under a continental plate.

Just to the east of the triple junction, beneath South America’s Patagonia region, a gap known as a slab window exists between the subducting oceanic plates. Caused by the subduction of the spreading center, the window exposes the overriding South American plate to hot mantle material from below.

Knowing the size and geometry of this opening is key for parsing out the area’s complex geology. However, limited offshore observations have left researchers unsure of where the slab window begins.

Recently, a new array of seismic stations deployed on the ocean floor off of Chile’s coast has boosted opportunities for observation. According to Azúa et al., the new seismic data help to pinpoint the beginning of the Patagonian slab window to just south of the Chile Triple Junction.

The seismic data captured shallow tectonic tremors, a type of “slow earthquake” that releases energy more gradually than conventional quakes—often over the course of several days. Slow earthquakes are increasingly being studied to enhance understanding of plate boundaries.

Using nearly 2 years’ worth of the new ocean bottom seismic data, the research team detected about 500 shallow tremors near the Chile Triple Junction. When they compared the locations of these tremors with the locations of previously detected conventional earthquakes, they noticed a distinct gap between where the two types of events occur.

The researchers interpret the gap in seismic activity as evidence of the youngest part of the Patagonian slab window, formed within the past 300,000 years.

Although further research will be needed to confirm and build on these findings, this work represents the first direct evidence of the offshore edge of this hole between the two subducting plates. (Geophysical Research Letters, https://doi.org/10.1029/2025GL115019, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), Finding the gap: Seismology offers slab window insights, Eos, 106, https://doi.org/10.1029/2025EO250299. Published on [DAY MONTH] 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.

Parts of Greater New Orleans are sinking by millimeters per year, increasing their vulnerability to floods and storm surges.

Flood protection infrastructure put in place in the months and years following Hurricane Katrina in 2005 could lose effectiveness more quickly than expected.

Though most of the city is stable, areas near the Louis Armstrong New Orleans International Airport, sections of flood protection walls, and certain industrial sites and wetlands are losing elevation, researchers reported in Science Advances earlier this summer. The rate and scale of these losses vary because rates of subsidence are affected by multiple factors, including groundwater pumping, wetland drainage, construction and urban development, and natural soil compaction.

Coupled with rising sea levels, the rapid subsidence could mean that without regular upgrades, flood protection infrastructure put in place in the months and years following Hurricane Katrina in 2005 could lose effectiveness more quickly than expected.

Spotting Subsidence from Above

As part of the new research, remote sensing expert Simone Fiaschi and his colleagues used interferometric synthetic aperture radar, or InSAR, to map subsidence across the city in 2002–2007 and 2016–2020. InSAR measures the distance between a satellite orbiting Earth and the planet’s surface. When averaged over measurements taken at different times, the satellite data can be used to detect millimeter-scale changes in elevation.

Knowing where and how quickly subsidence is occurring can clue scientists in to potential causes, said Fiaschi, who now works at the InSAR company TRE ALTAMIRA. “And that’s, of course, necessary if you want to intervene or…make adjustments to protect the city.”

During both periods, research showed that much of Greater New Orleans was stable, sinking or rising by less than 2 millimeters per year.

But a few hot spots revealed larger changes. For example, the area in and around the Louis Armstrong International Airport sank by up to 27 millimeters per year between 2016 and 2020, likely because of construction of a new terminal during that time.

Areas of concrete floodwall near the airport and along sections of the Mississippi River, built as part of the city’s $15 billion Hurricane and Storm Damage Risk Reduction System, also sank by more than 10 millimeters per year as the floodwalls settled.

Identifying Problem Areas

About half of New Orleans is already below sea level; even a small change in elevation raises the risk of flooding.

The city’s infrastructure may already be showing the effects of subsidence, said Krista Jankowski, a geoscientist at the consulting firm Arcadis who lives in New Orleans but did not participate in the new research. Filled potholes become artificial high spots as the land around them continues to sink, and fire hydrant collars that used to be level with surrounding lawns now sit several inches higher.

Wetlands within and beyond the floodwalls are sinking, too. Both natural erosion and human-driven water removal could be contributing to this subsidence.

“It’s an existential consideration for people who live in New Orleans.”

Other areas are even gaining elevation in response to human activity—or lack thereof. The Michoud neighborhood, in the city’s Ninth Ward, rose by up to 6 millimeters per year between 2016 and 2020. Until 2016, groundwater extraction by a local power plant caused Michoud to sink. But when the plant was decommissioned and pumping stopped in 2016, the water table started to recover and the land began to rebound. That finding showed that at least some of the subsidence can be fixed.

“I think that’s a nice aspect of the study, that it updates earlier studies and documents what parts have been fixed and what parts are still a problem,” said Tim Dixon, a geologist at the University of South Florida who was not involved in the new research.

Monitoring and managing subsidence is “an existential consideration for people who live in New Orleans,” Jankowski said. Having a better understanding of where subsidence is concentrated and how quickly those areas are sinking, she explained, will help “make sure we’re paying attention to places where there may be issues.”

—Skyler Ware (@skylerdware.bsky.social), Science Writer

Citation: Ware, S. (2025), Parts of New Orleans are sinking, Eos, 106, https://doi.org/10.1029/2025EO250300. Published on 14 August 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.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Earth and Space Science

Measurements of bathymetry, the underwater depth of the ocean floor, are typically done for shallow coastal waters from boats with echosounders or from aircraft using green-wavelength lidar. However, these methods can be expensive to field, hard to update, and cannot access all locations.

NASA’s Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) mission has introduced a new satellite-derived shallow water bathymetry product that will provide free, easy-to-access, and ready-to-use measurements for the world’s shallow coastal waters. This information is of value for navigational safety, in particular for measurements in very shallow water or close to shore where boats cannot safely operate. Scientists can also use the data to study coral reefs and near-shore aquatic habitats.

The shallow water bathymetry product is derived using data from the ICESat-2 green-wavelength Advanced Topographic Laser Altimeter System (ATLAS) lidar, which operates from an orbit about 500 kilometers above the Earth’s surface.

Parrish et al. [2025] present their results of the first processing of the ICESat-2 archive, providing bathymetric measurements from approximately 0.5 to 21.5 meters depth for 13.7 million kilometers of coastal waters. This initial data set has been validated against high accuracy airborne bathymetry data acquired over eight locations in the eastern United States and the Caribbean islands. The products will be regularly updated as ICESat-2 acquires new data, filling in areas not initially measured because of rough seas or cloud cover and updating earlier measurements over time.

 ​Citation: Parrish, C. E., Magruder, L. A., Perry, J., Holwill, M., Swinski, J. P., & Kief, K. (2025). Analysis and accuracy assessment of a new global nearshore ICESat-2 bathymetric data product. Earth and Space Science, 12, e2025EA004391. https://doi.org/10.1029/2025EA004391

—Cathleen Jones, Editor, Earth and Space Science

Text © 2025. The authors. CC BY-NC-ND 3.0
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The 200,000 cubic metre collapse of a rock pillar has destroyed two extremely challenging climbing routes.

At a time when there is a great deal going on in the landslide world, another really interesting event has almost passed me by. Thanks to loyal reader Scott for highlighting another remarkable event.

Overnight on 1 – 2 August 2025, a large rock pillar collapsed at Carne Wall in the Blue Mountains of New South Wales in Australia. This has destroyed a series of famously challenging climbing routes. ABC News has a really good article about the landslide – they estimate that the volume was about 200,000 m3.

This collapse at Carne Wall is located at [-33.65233, 150.33885].

On Facebook, Monty Curtis has posted a nice before and after image pair:-

Before and after images of the 1-2 August 2025 rockfall at Carne wall in the Blue Mountains of Australia. Images by Monty Curtis.

And there is a really fantastic before and after drone video posted to Youtube by Simmo:-

Failures of this type would normally be via a topple, but I wonder if the debris field supports that interpretation? An alternative might be that the toe of the pillar failed and collapsed, with the subsequent pillar failure involving more vertical movement. This still from Simmo’s video shows that the pillar had a remarkably narrow base, which would have been under a high compressive load.

A still from a drone video collected a week before the 1-2 August 2025 rockfall at Carne wall in the Blue Mountains of Australia. Video posted to Youtube by Simmo.

Perhaps the base of the pillar underwent progressive failure, leading to the collapse of the mass?

Either way, it was fortunate that there were no climbers on the pillar when it failed.

Return to The Landslide Blog homepage Text © 2023. The authors. CC BY-NC-ND 3.0
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