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Author(s): Feiyu Li, Seth Dorfman, and Xiangrong Fu

The parametric decay instability (PDI) of Alfvén waves—where a pump Alfvén wave decays into a backward-propagating child Alfvén wave and a forward ion acoustic wave—is a fundamental nonlinear wave-wave interaction and holds significant implications for space and laboratory plasmas. However, to date …

[Phys. Rev. E 112, 025206] Published Thu Aug 14, 2025

The Mediterranean Sea is particularly susceptible to marine heat waves—such as the record-breaking 2022 heat wave, which was characterized by anomalously high sea surface temperatures—due to the interplay of air-sea heat fluxes and local oceanographic processes, leading to significant impacts on marine ecosystems and coastal communities.

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
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

SummaryDetecting marsquakes is crucial for understanding the interior structure of Mars. However, the detection and analysis of such seismic events is challenging due to the strong background noise and low signal-to-noise ratios (SNR) of marsquake seismograms. Moreover, the volume of the seismic data needed to create an efficient method to detect marsquakes, and the required amplitudes of such events is limited by the low energy of the seismic. Here, we develop a new deep learning-based detection algorithm, MarsConvNet (MANet), which can fully exploit the latent information of seismic sequences by upsampling and downsampling for detecting marsquakes in the continuous seismic records. Our approach is to construct a deep encoder structure and nonlinear mapping relationship between seismic signals and arrival times of P and S waves by training on the STanford EArthquake Dataset (STEAD) from Earth. Application to the continuous waveform data from the InSight seismic data from 2019 to 2022 shows that the algorithm can detect marsquakes with weak amplitude in addition to reproducing all events detected manually by the Marsquake Service (MQS). Using our method, we detected 67 previously undetected marsquakes.

SummaryA new approach for the parallel forward modelling of transient electromagnetic (TEM) fields is presented. It is based on a family of uniform-in-time rational approximants to the matrix exponential that share a common denominator independent of the evaluation time points. The partial fraction decomposition of this family is exploited to devise a fast solver with high parallel efficiency. The number of shifted linear systems that need to be solved in parallel does not depend on the number of required time channels nor the spatial discretization. We also argue that similar parallel efficiency gains can be expected when solving the inverse TEM problem.

As human activity across the world's oceans expands, scientists are zeroing in on shifts in atmospheric composition—particularly ozone, a key player in marine atmospheric chemistry. In a new study, researchers have completed China's first shipborne ozone-sounding campaign in the South China Sea, yielding high-resolution data that addresses a gap in understanding oceanic ozone dynamics.

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

The Mendenhall River in Juneau, Alaska, reached a record-breaking crest Wednesday morning thanks to a glacial outburst flood (GLOF) from Suicide Basin. At 16.65 feet, the crest exceeded the previous record flood stage of 15.99 feet in 2024.

Image created for the National Weather Service webpage monitoring Suicide Basin, www.weather.gov/ajk/suicidebasin

As glaciers melt, they leave behind lakes that rest in valleys. The melting of the Suicide Glacier has created a glacial lake in Suicide Basin, which lies above the Mendenhall Glacier. The Mendenhall Glacier, about 12 miles (19 kilometers) north of Juneau, acts as an ice dam for the lake. But, when enough snowmelt and precipitation occur, the lake drains through and over the glacier into Mendenhall Lake and the Mendenhall River.

The basin has filled and drained at least 39 times since July 2011, according to the National Weather Service.

During the crest on Wednesday morning, a gauge at Mendenhall Lake recorded a peak streamflow of 47,700 cubic feet per second (1,350 cubic meters per second), according to USGS data. In August 2023, the same gauge recorded a streamflow of 25,200 cubic feet per second (714 cubic meters per second), which Andrew Park, a meteorologist at NWS Juneau, called “historic”  at the time. The highest recorded streamflow before that was 16,300 cubic feet per second (462 cubic meters per second), in 2016. During the 2023 event, Rick Thoman, Alaska Climate Specialist at the Alaska Center for Climate Assessment and Policy, also told Climate.gov that “Decades worth of erosion happened in one weekend.”

The City and Borough of Juneau installed barriers provided by the United States Army Corps of Engineers earlier in 2025. According to the city and borough’s website, the barriers are intended to be an “interim solution,” but are designed to protect against GLOFs up to 18 feet high (5.4 meters). According to USA Today, the barriers seem to have successfully held back most of the water.

 
Related

•  Suicide Basin Monitoring and Current Conditions
•  Juneau Glacial Flood Dashboard
•  National Weather Service Flood Statement
•  Update: Mendenhall River crests, levels now falling
 

A flood statement issued by the National Weather Service in Juneau urged residents to heed road closures and local emergency management team guidance.

Water levels above 15 feet are considered the “major flood stage.” Zoe Kaplan, a meteorologist at the National Weather Service in Juneau, said the office predicts levels will drop to moderate flood stage (below 12 feet) by early afternoon, and to minor flood stage (below 10 feet) by late afternoon.

GLOFs could grow more common as rising temperatures increase glacier melt around the world. A 2020 study found that the number, total volume, and total area of glacial lakes have each increased by about 50% between 1990 and 2018. And, according to the Environmental Protection Agency, Alaska has warmed faster than any other U.S. state, and faster than the global average, over the past 100 years.

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

These updates are made possible through information from the scientific community. Do you have a story idea about science or scientists? We’re listening! Send us a tip at eos@agu.org. Text © 2025. AGU. CC BY-NC-ND 3.0
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A new wave of climate research is sounding a stark warning: Human activity may be driving drought more intensely—and more directly—than previously understood.

An international team of researchers led by the University of Massachusetts Amherst has tracked changes in more than 114,000 rivers in High Mountain Asia over a 15-year period. The paper, published in AGU Advances, reported that nearly 10% of these rivers saw an increase in flow, with an increasing proportion of that water coming from glacial ice melt compared to precipitation.

Extreme rainfall in New Zealand from future cyclones could rise by up to 35%. New high-resolution modeling predicts that rainfall from tropical cyclones will significantly increase under global warming.

Researchers at The University of Alabama in Huntsville (UAH) have published a paper in Communications Earth & Environment that demonstrates for the first time that using data gathered on atmospheric particles from Chinese megacities to characterize air quality for U.S. urban centers leads to significant inaccuracies.

An international study led by Prof. Tamar Guy-Haim and Dr. Ximena Velasquez from the Israel Oceanographic and Limnological Research (IOLR) has revealed that tiny planktonic crustaceans carry a unique microbial signature that better reflects ocean currents and environmental gradients than microbes found freely in seawater.

As glaciers melt, huge chunks of ice break free and splash into the sea, generating tsunami-sized waves and leaving behind a powerful wake as they drift away. This process, called calving, is important for researchers to understand. But the front of a glacier is a dangerous place for data collection.

On May 12, 2008, the magnitude 7.9 Wenchuan earthquake shook central China, its destructive tremors spreading from the flank of the Longmen Shan, or Dragon's Gate Mountains, along the eastern margin of the Tibetan Plateau.

In the journal Nature, 21 leading scientists prescribe ways to use food systems to halt and reverse land degradation, underlining that doing so must become a top global priority to mitigate climate change and stop biodiversity loss.

For more than 50 years, scientists have debated whether a massive ice shelf—up to 1 kilometer thick—covered the entire Arctic Ocean during past ice ages, transforming the frigid water into a solid icy surface similar to Antarctica’s Ross Ice Shelf.

The hypothesis dates to the 1970s, when British glaciologist John Mercer and others proposed that during extremely cold periods, continental ice sheets would have extended far into the Arctic Ocean. It gained support in the 1990s when researchers began finding evidence of scouring on the seafloor, indicative of large, kilometer-thick ice running aground.

“We found out that even close to the Norwegian coast, there was still open water, which completely contradicts the hypothesis of a big ice shelf covering the Arctic Ocean.”

But new data published in Science Advances add evidence against such a “pan-Arctic” ice shelf, instead suggesting that seasonal sea ice, rather than a continuous ice shelf, dominated parts of the Arctic Ocean over the past 750,000 years.

“We found out that even close to the Norwegian coast, there was still open water, which completely contradicts the hypothesis of a big ice shelf covering the Arctic Ocean,” said coauthor Gerrit Lohmann, a climate modeler from the Alfred-Wegener-Institut in Germany. However, some experts argue that the results alter merely the timing and location of Arctic ice shelves.

Reading Ancient Algae

Instead of analyzing seafloor scars, the study’s authors looked at what was living in ancient seafloor sediment. They analyzed two sediment cores drilled from the Arctic Ocean between Europe and Greenland, searching for molecules produced by marine algae such as diatoms and dinoflagellates before the organisms died and sank to the seafloor.

Some species of alga grow on the underside of seasonal sea ice, and others thrive in open water. Their presence or absence within sediment deposited at a given time signals whether sea ice was present when they were living. Levels of calcium in the sediment can also indicate the production of marine organisms in surface waters.

By searching for organisms’ unique chemical signatures in dated sections of the cores, the scientists could conclude whether and when a solid ice shelf completely covered the ocean surface.

The results showed evidence of both seasonal sea ice and open water over the past 750,000 years, with one exception, around 676,000 years ago, when the chemical signature of the key marine life decreased for roughly 55,000 years.

On a train home after a funding interview, the study’s first author, Jochen Knies, was discussing the sediment core findings with Lohmann, who immediately recognized that the computational climate model he worked on, the high-resolution AWI Earth System Model, might offer additional data on the sea ice conditions during that time. “We discussed it for hours, maybe disturbing others on the train,” Lohmann said.

After some testing, he found that the model independently predicted that the same regions covered by the core samples would have had open water and seasonal sea ice instead of a continuous ice shelf, even during the coldest periods. “I was fascinated to see that in the time slices that [Knies] was interested in, the sea ice was even partly absent in summer,” Lohmann said of the modeling results. “It was completely the opposite of other hypotheses.”

“I would have assumed that where they found open water, there should have been times when this Arctic Ocean ice shelf moved into the area, and apparently it didn’t,” said Johan Nilsson, a paleoceanographer at Stockholm University in Sweden who was not involved in the new study but has published seafloor evidence of an Arctic Ocean ice shelf.

The Debate Continues

To Nilsson, the results don’t completely refute the possibility of large Arctic Ocean ice shelves; instead, they redefine their possible boundaries. “I think for me, it pushes back the edge of Arctic Ocean ice shelves a bit further north of Svalbard,” Nilsson said.

The authors of the new study “don’t see ice shelves in the Norwegian-Greenland sea, but that doesn’t mean that they didn’t exist in the Arctic.”

Leonid Polyak, a retired paleoceanographer at the Ohio State University who was not involved in the research, said the new study reveals “a very strong set of data.” He noted, however, that the evidence for Arctic ice shelves is strong, and the debate over whether they came together into one pan-Arctic ice shelf is “a bit overblown.”

“Pretty much everyone agrees that there have been ice shelves in the Arctic Ocean. The question is, When exactly did they exist, for how long, and where?” Polyak said. The authors of the new study “don’t see ice shelves in the Norwegian-Greenland sea, but that doesn’t mean that they didn’t exist in the Arctic.”

Lohmann acknowledged that mysteries remain in the Arctic and that the pan-Arctic ice shelf debate may not be settled. “I feel the final word hasn’t been spoken,” he said.

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

Citation: Chapman, A. (2025), Arctic ice shelf theory challenged by ancient algae, Eos, 106, https://doi.org/10.1029/2025EO250298. Published on 13 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: AGU Advances

What do many baked goods and the planet Mercury have in common? They shrink as they cool.

Evidence suggests that since it formed about 4.5 billion years ago, Mercury has continuously contracted as it has lost heat. And somewhat like a fresh-baked cookie or cheesecake, Mercury also cracks as it cools: Thrust faults cut through the planet’s rocky surface to accommodate the ongoing shrinking.

By observing how faults have uplifted parts of Mercury’s surface, researchers can begin to estimate how much Mercury has contracted since it formed. However, prior estimates have varied widely, suggesting that thanks to faulting resulting from cooling, Mercury’s radius has shrunk by anywhere from about 1 to 7 kilometers.

To resolve this discrepancy, Loveless and Klimczak employed an alternative method for estimating shrinkage caused by cooling-induced faulting on Mercury.

Prior estimates all relied on a method that incorporates the length and vertical relief of uplifted landforms, but that produces different shrinkage estimates depending on the number of faults included in the dataset. In contrast, the new method’s calculations are not reliant upon the number of faults. Rather, it measures how much the largest fault in the dataset accommodates shrinkage, then scales that effect to estimate the total shrinkage.

The researchers used the new approach to analyze three different fault datasets: one including 5,934 faults, one including 653 faults, and one including just 100 faults. They found that no matter which dataset was used, their method estimated about 2 to 3.5 kilometers of shrinkage. Combining their results with prior estimates of additional shrinkage that may have been caused by cooling-induced processes other than faulting, the researchers concluded that since Mercury’s formation, the planet’s radius may have shrunk by a total of 2.7 to 5.6 kilometers.

The new estimates could help deepen the understanding of the long-term thermal history of Mercury. Meanwhile, the authors suggest, the same methodology could be used to investigate the tectonics of other planetary bodies, like Mars, that feature faults. (AGU Advances, https://doi.org/10.1029/2025AV001715, 2025)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2025), How much has Mercury shrunk?, Eos, 106, https://doi.org/10.1029/2025EO250301. Published on 13 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: Geophysical Research Letters

The Pacific Decadal Oscillation (PDO) is a slowly evolving pattern of ocean temperature anomalies in the North Pacific that can influence climate and ecosystems across the globe. The climate science community and stakeholders are increasingly interested in how well we can predict the PDO from months to years in advance, but such predictions are not equally reliable at all times of year. As the PDO is part of a coupled ocean-atmosphere system, such simulations are very resource intensive.

Meeker et al. [2025] use the Seasonal to Multi Year Large Ensemble (SMYLE)—a large ensemble of initialized decadal hindcast simulations with the fully coupled Community Earth System Model 2 (CESM2)—to show that while the PDO is predictable up to one year in advance, skill drops off most rapidly during late fall and spring, a seasonal pattern that mirrors known challenges in forecasting El Niño events in the tropical Pacific. Using a simple statistical model, the authors further show that much of the PDO’s predictability comes from persistence—the ocean’s tendency to stay in the same state for a while—but atmospheric teleconnections from the tropical Pacific also play an important role.

The results highlight that when El Niño is hard to predict, so is the PDO. Understanding when and why these prediction skill drops happen is important for improving seasonal forecasts that support fisheries, agriculture and water management. This work also shows how relatively simple linear models can help diagnose behavior in more complex models of the coupled climate system, enabling benchmarking and improvement of more advanced forecasting systems.

Citation: Meeker, E. D., Maroon, E. A., Deppenmeier, A. L., Thompson, L. A., Vimont, D. J., & Yeager, S. G. (2025). Seasonality of pacific decadal oscillation prediction skill. Geophysical Research Letters, 52, e2025GL116122. https://doi.org/10.1029/2025GL116122

—Kristopher B. Karnauskas, Editor-in-Chief, Geophysical Research Letters

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.

The location of this major event has now been identified. It was a major rock slope failure that ran out across the South Sawyer Glacier.

The Alaska Earthquake Center has now provided a detailed update about the 10 August 2025 landslide that occurred in the area of Tracy Arm. This work has been led by Ezgi Karasözen, one of the Earthquake Center’s research scientists, so the credit must go to them.

They have posted a very informative page that describes the seismic detection of the landslide, provides eyewitness accounts of the damage that it caused and outlines how they have gone about finding the landslide. This is unusually good public communication about a large event – so well done to them.

They have also published some imagery from their initial reconnaissance of the landslide. Meanwhile, they have also posted to Facebook a short video of the landslide itself – Wordpress won’t allow me to embed this, so this is the link:-

https://www.facebook.com/reel/2164841844024421

The footage was captured by LT Chip Baucom and CDR PJ Johansen of the U.S. Coast Guard. There are two stills that are very helpful in providing an initial view of this landslide. First, this is view of the scar and the deposit – note that the landslide has failed onto the  South Sawyer Glacier.

An initial view of the 10 August 2025 landslide onto the South Sawyer Glacier. Image from a video collected by the US Coast Guard, posted to Facebook by the Alaska Earthquake Center.

This appears to be a large, joint-controlled rock slope failure, with the appearance of a wedge (or several wedges, perhaps).

Second, the video captures the track of the landslide down the glacier towards the fjord:-

An initial view of the track of the 10 August 2025 landslide over the South Sawyer Glacier. Image from a video collected by the US Coast Guard, posted to Facebook by the Alaska Earthquake Center.

This appears to have been a landslide with high mobility – probably the consequence of a large volume and the movement over a low friction surface (ice).

The Alaska Earthquake Center highlights that the seismic instruments detected about 100 small events in the hours leading up to the final collapse. This will be a rich dataset to understand the failure process.

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.

AbstractDesert strata consist of dune and interdune deposits, and they have different magnetic properties. Contrasting magnetic properties of these two types of strata is a foundation for extracting paleoclimate information from dune-interdune strata in these eco-fragile regions, but few have done so. Here we compared magnetic properties between dune and interdune strata from the late Miocene desert deposits in the northwestern Tarim Basin. We found that interdune strata displayed enhanced magnetic properties mainly due to content increase of stable single-domain (SSD) and small pseudo single-domain magnetite (PSD) within chlorite layers. But magnetic enhancement in interdune strata does not correspond with content increase of superparamagnetic (SP) ferrimagnetic minerals. Our high-resolution transmission electron microscope results suggest pedogenic SSD and small PSD magnetite form within chlorite layers, and we propose weathering of chlorites resulted in high concentration of Fe (II) and Fe (III) ions within layers, facilitating the formation of SSD and small PSD magnetite. By contrast, dry climate in the Tarim Basin results in micropore spaces between mineral particles having limited concentration of Fe (II) and Fe (III) ions, inhibiting SP magnetite formation. This pattern is different from Chinese loess-paleosols sequence, where magnetic enhancement is accompanied with content increase of both SP and SSD or small PSD ferrimagnetic mineral content. Therefore, magnetic enhancement pattern differences (whether magnetic enhancement is accompanied with SP magnetite formation) may inform climate conditions. To infer environmental variations in arid regions using magnetic parameters, reliance on proxies that indicate the relative content of ferrimagnetic grains or content of magnetic grains with stable remanence is essential.