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

Climate change reshapes landscapes by altering rainfall, the primary driver of erosion in coupled mountain–basin systems. Yet more rainfall does not necessarily translate into more erosion. Using a two-dimensional numerical model that integrates hillslope processes, river incision, and sedimentation, Luo et al. [2025] reveal a previously underappreciated phenomenon: erosion saturation. When the duration of climate variability exceeds the intrinsic response time of the landscape, the system reaches a state in which additional rainfall fails to amplify erosion. Instead, sedimentation increasingly regulates the system, dampening sediment flux despite continued climatic forcing.

By explicitly comparing the period of climate forcing (P) with the landscape response time (τ), the study introduces a simple and transferable framework for understanding how climatic signals are filtered before being archived in sedimentary records. This mechanism helps explain why some long-period climate oscillations, including those linked to Milankovitch cycles, may leave muted or phase-shifted signatures in downstream deposits. Importantly, erosion saturation is not limited to strictly periodic forcing and may also emerge under prolonged or stepwise climate changes.

These findings bridge a longstanding gap in source–sink research by emphasizing that mountains and basins function as a dynamically coupled system rather than independent sediment producers and receivers. The work also highlights the need to incorporate additional controls—such as spatially variable uplift and vegetation dynamics—into future models of landscape evolution under climate change.

Citation: Luo, T., Yuan, X., Guerit, L., & Shen, X. (2025). Erosion saturation of mountain-basin system in response to rainfall variation. Journal of Geophysical Research: Earth Surface, 130, e2025JF008649. https://doi.org/10.1029/2025JF008649

­­­­­­­­­­­­­­­­­­—Dongfeng Li, Associate Editor, JGR: Earth Surface

Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Source: GeoHealth

West Nile virus is the most common mosquito-borne illness in the continental United States and can in rare cases lead to a much more serious disease with an approximately 10% fatality rate. West Nile virus neuroinvasive disease (WNND) has resulted in around 3,000 deaths since its introduction to the country in 1999, but to date no national forecast for the disease exists.

Harp et al. developed a climate-informed, regionally determined forecast method for WNND cases across the United States that outperforms current benchmarks. Key to their success was aggregating historically low county-level caseloads to the regional level, the authors say. Their work highlights key climatic factors and how their regional variation affects WNND rates.

Both mosquitoes and passerine birds (a group that includes more than half of all bird species) are vectors for West Nile virus, meaning caseloads are contingent on the environmental factors affecting these species. The authors picked the most relevant climatic factors as model inputs for each region. They found that drought and temperature are most strongly linked to WNND cases overall, and precipitation is linked in some regions. The central United States saw the most consistent correlation with drought and WNND cases, whereas the northern parts of the country saw the strongest link between WNND and warmer winter and spring temperatures.

The authors compared their climate-driven model with previous benchmark models, including a simple historical caseload model and an ensemble model from a 2022 competition. They found their model consistently outperformed others across regions. Nationally, a version of their model that included both primary and secondary climate factors (such as temperature and soil moisture) offered a prediction improvement of 21.8% over the historical model.

While the advancement represents a building block toward operational West Nile virus forecasts, the authors recommend that future work focus on enhancing county-level forecasting, which would provide authorities with more actionable information to prepare for fluctuations in WNND caseloads. Future WNND forecast models may also need to overcome the issue of climate data latency to offer real-time predictions, the authors say. One option could be to incorporate weather and climate forecasts into modeling, allowing disease forecasts to look further ahead. (GeoHealth, https://doi.org/10.1029/2025GH001657, 2026)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2026), New method could improve U.S. forecasting of West Nile virus, Eos, 107, https://doi.org/10.1029/2026EO260065. Published on 20 February 2026. Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

The climate crisis is warming Antarctica fast, with potentially disastrous consequences. Now scientists have modeled the best- and worst-case scenarios for climate change in Antarctica, demonstrating just how high the stakes are—but also how much harm can still be prevented.

SummaryModeling crustal deformation induced by fault slip is a fundamental problem in structural geology and seismology. However, the challenges of data sparsity and spatial discontinuity impose significant limitations on conventional forward and inverse methods, often resulting in low computational efficiency and limited accuracy. Although AI-based approaches such as Physics-Informed Neural Networks (PINNs) and Physics-Encoded Finite Element Networks (PEFEN) offer new solutions for sparse-data problems governed by physical laws, their underlying assumption of spatial continuity conflicts with the inherent displacement discontinuities of fault-slip fields. To address this limitation, we propose a novel method—the Split-Node Physics-Encoded Finite Element Network (SN-PEFEN)—which integrates the node-splitting mechanism into the PEFEN framework. By explicitly encoding spatial discontinuities into the nodal topology during mesh preprocessing, SN-PEFEN not only overcomes the theoretical limitations of existing PEFEN models in handling discontinuous fields but also maintains physical consistency. We apply SN-PEFEN to perform forward and inverse modeling of deformation fields induced by complex fault slip in both 2D and 3D heterogeneous media. For a model with over one million degrees of freedom, the forward simulation achieves over 40× speedup compared to traditional FEM (∼1,800 s vs. 42 s), while maintaining comparable accuracy. In inverse modeling, the solution converges within only 100 iterations, with a total runtime of approximately 2,000 s, demonstrating high computational efficiency. This method establishes a new high-efficiency paradigm for analyzing complex discontinuous deformation in geomechanics, offering promising applications in multi-fault system analysis and fault-slip inversion. Furthermore, SN-PEFEN facilitates rapid, physics-based assessments for emergency seismic response and disaster management, while laying the groundwork for next-generation data-driven regional earthquake early warning systems.

Forest loss does more than reduce tree cover. A new global study involving UBC Okanagan researchers shows it can fundamentally change how watersheds hold and release water. The research, published in the Proceedings of the National Academy of Sciences, analyzed data from 657 watersheds across six continents.

Researchers have identified a "tipping point" about 2.7 million years ago when global climate conditions switched from being relatively warm and stable to cold and chaotic, as continental ice sheets expanded in the Northern Hemisphere. Following this transition, Earth's climate began swinging back and forth between warm interglacial periods and frigid ice ages, linked to slow, cyclic changes in Earth's orbit. However, glacial periods after this tipping point became far more variable, with large swings in temperature over relatively short timescales of roughly a thousand years.

Each year, the world's leading climate scientists evaluate the most critical evidence on how our planet is changing. Their assessments draw heavily on data from Earth-observing satellites—and the latest report delivers a stark warning: the planet's energy balance is drifting further out of alignment, ocean warming is now accelerating, and the land's capacity to absorb carbon is declining, along with other troubling trends.

In a world-first use of medical imaging technology, scientists have revealed the earthquake-generating potential of faults in the Hamilton and Hauraki areas. The study shows that hidden geological faults in Hamilton city and newly studied faults in the Hauraki district are capable of generating moderate to large earthquakes, and have done so in the past 15,700 years.

One way scientists search for Earth-like planets is the transit method, which involves observing a slight dimming in starlight when a planet passes in front of its star. Transits cause very small decreases in flux: A planet the size of Jupiter might block 1% of the light from a Sun-sized star, and an Earth-sized planet might block only 0.01%.

A study recently published in The Astrophysical Journal Letters suggests that an intriguing signal from the star HD 137010 comes from the transit of a planet about the size of Earth with a similar orbit. Astronomers detected the faint signal using data from NASA’s K2 mission.

HD 137010 is dimmer than the Sun, and the new planet candidate, HD 137010 b, likely lies near the outer edge of the star’s habitable zone. As a result of these factors, HD 137010 b receives far less energy from its star than the Earth receives from the Sun.

Detecting Single-Transit Events

HD 137010 b is the smallest potential planet to be detected from a single transit around a Sun-like star.

“Detecting single transit events is computationally difficult, so it’s sometimes actually easier for a human to pick out these events from the data—as was the case here,” Alexander Venner, an astrophysicist at the Max Planck Institute for Astronomy and lead author of the study, wrote in an email to Eos.

Data came from the K2 mission, which itself relied on the Kepler mission, NASA’s primary mission to find Earth-like planets orbiting Sun-like stars. After the Kepler spacecraft lost some functions, the K2 mission reused Kepler’s telescope to study brighter stars with high precision. Though each of K2’s observation campaigns lasted only about 80 days, too short to catch transiting planets with longer orbital periods, the mission still managed to discover planets from single-transit events.

“I knew there was something to it as soon as I saw it.”

The team noticed a 10-hour transit across the bright star HD 137010 in 2017. The telescope was precise enough to see the star clearly, even though its light dimmed only slightly, by 225 parts per million. Venner said some planetary scientists compare the effect to a moth passing in front of a lighthouse.

Still, Venner said the transit signal was significant enough that “I knew there was something to it as soon as I saw it.”

Even though Venner and the team were confident that the signal was significant, they still had to make sure the signal wasn’t a false alarm caused by background stars or quirks in the data.

To rule this out, the team carefully checked for any stars close to HD 137010. Radial velocity data, Hipparcos and Gaia astrometry, archival images, and high-resolution imaging showed no signs of stars falling within the K2 photometric aperture. Because only one transit was seen, astronomers can’t yet be certain it was caused by a planet, but the candidate was designated HD 137010 b.

Planetary Properties and Habitability

The new analysis suggests the radius of HD 137010 is about the same as Earth’s, and its orbital period is about 365 days. Using the planet’s orbit and the star’s brightness, the team estimated that HD 137010 b receives only about 0.3 times the amount of sunlight as Earth.

HD 137010 b is one of the coldest Earth-sized planets seen crossing a Sun-like star. Its surface may be as cold as −68°C (−90°F), even colder than Mars, which averages about −65°C (−85°F).

“Whether its surface is at all ‘Earth-like’ depends on the properties of its atmosphere, which we just can’t constrain from the current data,” Venner said. “A thick warming atmosphere might allow for a warm wet surface, but a thin atmosphere might result in a completely frozen surface colder than Mars.”

Future Prospects

This “represents a milestone in the search for worlds that might one day be considered truly Earth-like.”

“This is, indeed, an exciting result. It represents a milestone in the search for worlds that might one day be considered truly Earth-like,” Jon Jenkins, who served as the coinvestigator for data analysis on the original K2 mission but was not part of the research, wrote in an email to Eos.

“It will be extremely interesting if future observations give us information on the atmosphere or surface properties of HD 137010 b,” Venner said. “These scenarios could be distinguished if we’re able to observe the spectrum of HD 137010 b.”

—Pranjal Malewar (@PranjalMalewar), Science Writer

Citation: Malewar, P. (2026), This potential exoplanet is Earth sized but may be colder than Mars, Eos, 107, https://doi.org/10.1029/2026EO260062. Published on 19 February 2026. Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Despite decades of industrial deposition, nitrogen availability in the boreal forest is steadily declining. In a new study published in Nature, researchers from the Swedish University of Agricultural Sciences using decades of unique, stored data have found that atmospheric CO₂ is the main driver.

Western Australian hydrothermal and magmatic deposits that formed several hundred kilometers apart more than two and half billion years ago share more commonalities than previously thought.

Western Australia's jarrah forests were unevenly impacted by the record-breaking 2023–2024 heat wave and subsequent drought, with some areas experiencing more severe tree die-off than others, according to a new study.

To date, 42 landslides have been identified on Mauao (Mount Manganui) in New Zealand following the 22 January 2026 rainfall event.

The extreme rainfall event that affected parts of the North Island of New Zealand triggered two fatal landslides, of which the major failure at the Mount Maunganui Beachside Holiday Park on the flanks of Mauao was the most severe. In total, six people were killed in this failure, an unusually high total for a landslide in New Zealand.

As the clear up continues, work is underway to understand the scale of the problem on Mauao (Mount Managanui), the 232 m high lava dome that sits on the edge of the Bay of Plenty. Tauranga City council has a webpage providing updates on its ongoing work at Mauao, which includes an update published today. This highlights that 42 landslides have been identified on the walking tracks of Mauao, twelve of which are considered to be “severe” for which the impacts “generally involve high complexity, higher cost, longer timeframes, and often require staged or multi-disciplinary interventions.”

The Council has released this image showing some of the impacts:-

Landslides on Mauao following the 22 January 2026 rainfall event. Image from Tauranga City council.

This Planet Labs image, captured with their standard PlanetScope instrument on 15 January 2026, shows Mauao before the landslides:-

Satellite image of Mauao before the 22 January 2026 rainfall event. Image copyright Planet Labs, used with permission, captured on 15 January 2026.

And here is an image from five days after the 22 January 2026 event:-

Satellite image of Mauao after the 22 January 2026 rainfall event. Image copyright Planet Labs, used with permission, captured on 27 January 2026.

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

Images by Planet Labs:- https://www.planet.com/

The fatal landslide occurred on the eastern side of Mauao just below the 3 o’clock position – this is clearly visible. But other landslides can be seen on the eastern side at the end of the beach and further to the north, and on the southwestern side too. In some cases, the impact of the landslides on the walking tracks is clear.

Resolving these landslides will be time consuming and expensive, yet another burden on a large country with a comparatively small population. Tom Robinson of the University of Canterbury has a very nice article about the impact of landslides on New Zealand, noting that they have claimed 1,800 lives over the last two centuries, twice the number killed by volcanoes and earthquakes combined. As extreme rainfall events increase in frequency and severity, the challenges for New Zealands are intensifying.

Acknowledgement

Many thanks to the wonderful people at Planet Labs for providing access to the satellite imagery.

Return to The Landslide Blog homepage Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

SummaryUltralow velocity zones (ULVZs) at the Earth’s core-mantle boundary (CMB) are marked by substantial reductions in seismic velocities. They are often associated with significant increases in density, providing important insights into deep Earth composition and dynamics. In this study, we investigate ULVZs beneath eastern and southern Asia, regions associated with long-term subduction, by analyzing high-frequency (~1 Hz) ScP waveforms recorded at the small-aperture KZ array. After correcting for attenuation along the ScP path, we perform a grid search to match the observed waveform complexities with synthetics generated for a comprehensive suite of 1D ULVZ models. The best-fitting models for each event constrain ULVZ thickness, P- and S-wave velocity reductions, and density anomalies, revealing widespread but laterally variable ULVZ structures, although the influence of finite ULVZ geometry cannot be entirely excluded. The correlations among these parameters point to iron-rich chemical heterogeneity as the dominant origin of the imaged ULVZs, likely reflecting iron enrichment associated with long-term subduction processes.

SummaryWe introduce Virtual Seismic Arrays, which predict full array recordings from a single reference station, eliminating the need for continuous deployment of all stations for continued array operation. This innovation can reduce costs and address logistical challenges while maintaining multi-station functionality. We implement a Virtual Seismic Array using a deep learning encoder-decoder approach to predict the transfer of the seismic wavefield between stations. We train on recordings of secondary ocean microseisms from the Gräfenberg array in Germany to retrieve predictive models for each array station, which together form the Virtual Seismic Array. To evaluate its performance, we beamform original and predicted waveforms to detect the dominant secondary microseism sources. We assess three source regime scenarios: one where only a single dominant source regime is present in both the training and test dataset, another with two different regimes in the training data but only one in the test data, and a third where the training data does not contain the dominant source regime observed in the test data. Our results show strong agreement between predicted and original beamforming results in cases where the observed source regime was part of the training, demonstrating the feasibility of Virtual Seismic Arrays.

A new study published in the Journal of Climate reveals how surface warming in Antarctica, particularly over the Antarctic Peninsula, is significantly altering the stability of the lowest layers of the atmosphere.

An earthquake typically sets off ruptures that ripple out from its underground origins. But on rare occasions, seismologists have observed quakes that reverse course, further shaking up areas that they passed through only seconds before. These "boomerang" earthquakes often occur in regions with complex fault systems. But a new study by MIT researchers predicts that such ricochet ruptures can occur even along simple faults.

The Antarctic ice sheet does not behave as one single tipping element, but as a set of interacting basins with different critical thresholds. This is the finding of a new study by the Potsdam Institute for Climate Impact Research (PIK) and the Max Planck Institute of Geoanthropology (MPI-GEA). With today's warming, about 40% of the ice stored in West Antarctica may already be committed to long-term loss, while parts of East Antarctica could cross thresholds at moderate levels of warming between 2 to 3°C compared to pre-industrial levels, contributing significantly to global long-term sea-level rise.

About 56 million years ago, Europe and North America began pulling apart to form what became the ever-expanding North Atlantic Ocean. Vast amounts of molten rock from Earth's mantle reached the ocean floor as the crust stretched and thinned, creating a volcanic, rifted margin between Norway and Greenland, a marine feature that has intrigued scientists for decades.

In the whole history of Earth's climate, few events are as extreme as those that geologists call "Snowball Earth."