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The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.

In the last few days, two really interesting and useful updates have been published covering the 3-4 October 2023 GLOF in the Teesta Valley in India and the 26 August 2026 landslide in Nepal and Tibet.

Regarding the 3-4 October GLOF in the Teesta Valley in India, the ever-impressive Praful Rao has posted an article on the Save The Hills blog that uses satellite imagery to chronicle the impact of the flood. As Praful puts it:

“…these images provide an important historical record of the largest GLOF in the Himalayas. When juxtaposed with earlier images of the same areas from 2022, they reveal the extraordinary scale and humongous power of nature as the GLOF swept down the Teesta Valley.”

To give you an idea of the scale of this piece of work, here is one of the image pairs that Praful has posted:-

Before and after image of the 2023 Teesta Valley GLOF, posted to the Save The Hills blog by Praful Rao.

And here is a photo, also posted by Praful, of the aftermath of the GLOF in that town, Chungthang:-

The aftermath of the 2023 Teesta Valley GLOF in Chungthang, posted to the Save The Hills blog by Praful Rao.

Turning now to the 26 August 2026 landslide in Nepal and Tibet, the Youth Innovation Lab in Nepal has posted a very interesting review of the event – the document is here as a PDF.

This reports on a workshop convened a couple of weeks after the event by the Youth Innovation Lab with the Red Cross Red Crescent Climate Centre, Kathmandu University and the University of Twente, with the Ministry of Energy, Water Resources and Irrigation. It included local and international experts and it examines the event itself, the response and early lessons learnt.

For example, it provides an initial analysis of the range of parameters involved in the landslide, debris flow and debris flood provided by different analyses:-

The range of parameters involved in the 26 August 2026 landslide, debris flow and debris flood in Nepal and Tibet, from the Youth Innovation Lab report.

There is a huge range of information in this report, including an examination of the potential role of the rapidly changing climate in these high elevation Himalayan regions. It is well worth a read.

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Eighty years ago, a massive tsunami devastated parts of Hawaii, Alaska, Washington and Oregon following an earthquake off the coast of Alaska. A Michigan State University team is launching a project to study the underwater fault system where it originated—and whether it still poses a risk today.

SummaryReciprocal measurements are standard for data quality control in electrical resistivity surveys, but their potential as an interpretation tool is rarely exploited. Under the assumption of linear subsurface behaviour, normal and reciprocal readings should yield the same results, but when a systematic offset is present it can be indicative for additional processes. Here we present a time-domain induced polarization (TDIP) dataset from a volcanic hydrothermal system (Reykjanes, Iceland) where a strong, systematic offset between normal and reciprocal measurements is observed. The discrepancy is present as a positive shift of the reciprocal decay curves (>100 mV/V). While both normal and reciprocal inversions resolve a strong IP anomaly in the southern part of the profile, a substantial offset exists between the two ( >20 mS/m). The offset is spatially confined and persistent over 100 consecutive days, the anomaly itself coincides with a strong IP response attributed to the mutual occurrence of clay minerals and disseminated iron sulphides and oxides. Besides random noise, we evaluate four possible mechanisms for the offset: (1) polarization of the electrodes, (2) inherent sensitivity differences between normal and reciprocal configurations, (3) stray currents from the nearby powerplant and (4) nonlinear IP effects where the response depends on the current density. Given the geological context and the localized nature of anomaly, a non-linear effect is plausible but the ambiguity between systematic noise and a genuine subsurface signal cannot be fully resolved with field data alone. This study demonstrates that the systematic analysis of normal-reciprocal misfit in TDIP can serve as a widely accessible tool for identifying signals that, whether geologic, or anthropogenic in origin, are overlooked by standard data quality workflows.

Have you ever wondered what Earth observation satellites see when they look down at the deep ocean or a dense tropical forest during the dead of night? The answer, for the most part, is nothing. Standard optical sensors require a steady stream of light to function, and in these photon-limited regions, they hit a hard physical boundary. But what if we could rewrite the rules of optical imaging? By borrowing techniques from quantum photonics, we can push beyond these classical limits and unlock a fundamentally new way to observe the darkest and most hidden environments on our planet.

Explosive volcanic eruptions can be as destructive as they are difficult to predict, launching pyroclasts—the fragments of magma and rock blasted from a volcano—into the air and surrounding areas. These particles can have wide-ranging impacts, as seen during this summer's eruption of Mount Etna in Italy, when ash fell over the nearby city of Catania and closed its international airport for weeks. The size of erupted pyroclasts helps determine how far they travel and the hazards they pose. However, exactly how and where they form has remained poorly understood.

Microplastics are a modern environmental menace and a potential threat to human health. These tiny pieces of plastic, measuring from 1 to 5,000 micrometers, come mainly from larger plastics as well as sources such as paints and cosmetics. They are found in almost every corner of the planet, and a new study published in Science suggests rivers may be carrying far more of them into the ocean than previously thought.

Researchers have shown how dramatic sea-level rise over a 5,000-year period profoundly changed the coasts of northern Italy, Slovenia and northern Croatia. Successive shaping and reshaping of coastal features influenced the lives of Mesolithic and Neolithic people and the development of local communities. Land that hunter-gatherers once roamed and farmers later tended now lies deep beneath the sea.

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

15 September: The EPA announced the repeal of power plant carbon dioxide limits that had been finalized in 2024 and proposed to repeal all remaining greenhouse gas emissions standards for power plants at the G20 Energy Abundance Ministerial on 14 September in Houston, Texas.

In the announcement, the EPA stated that “models continue to show that [greenhouse gas] emissions from power plants have no material impact on global climate change,” and that “if all carbon dioxides were eliminated tomorrow, there would be no meaningful climate impact.” Power plant greenhouse gas emissions are the United States’ second-largest source of climate pollution and contributed 5% of total worldwide greenhouse gas emissions from 1990-2022.

14 September: Today, the EPA will announce the repeal of federal limits on power plant carbon dioxide emissions, finalizing a proposed rule that the agency has been considering since last spring. 

The repeal means that coal-, oil-, and gas-powered electricity plants in the United States will no longer need to limit their carbon dioxide emissions in accordance with regulations set in 2024. Those rules required existing coal-powered and new gas-powered plants to control 90% of their carbon pollution. At the time, the Biden administration estimated that the rules would result in tens of billions of dollars’ worth of public health benefits. 

The agency is also expected to announce a separate proposal to eliminate all greenhouse gas standards from power plants beyond the Biden-era regulations by arguing that it lacks the authority to create such regulations under the Clean Air Act and that such emissions do not pose a public health threat.

“Leaving this pollution unchecked ignores the Supreme Court, puts the public at risk, and flagrantly violates EPA’s legal responsibilities.”

Lee Zeldin, EPA administrator, is expected to announce the news at a summit of energy administrators today in Houston, Texas, according to Bloomberg News.

Last year, the agency justified the repeal of the 2024 regulations by arguing that carbon emissions are “global in nature,” and that any public health harms to U.S. residents could not be attributed to U.S. emissions alone. But the U.S. power sector contributes a large fraction of global greenhouse gas emissions: If it were its own country, it would be the fifth-biggest greenhouse gas emitter in the world, according to 2022 data. 

In a public comment on the proposal last year, lawyers and scholars at the New York University School of Law’s Institute for Policy Integrity wrote that the proposed repeal was “not supported by the law or the facts.”

In the comment, authors pointed out that the proposal ignored the climate impacts of such a repeal, such as an estimated $225 billion in global health damages. In 2024, the Biden administration estimated that the regulations would have prevented up to 1,200 premature deaths, 360,000 cases of asthma symptoms, 48,000 school absence days, and 57,000 lost work days in 2035 alone. 

The repeal and the new proposal are expected to face challenges in court. “The Supreme Court has made clear that EPA has an obligation to control greenhouse gas emissions from power plants under the Clean Air Act,” Dena Adler, a senior attorney at the Institute for Policy Integrity, wrote in a statement about today’s announcement. “Leaving this pollution unchecked ignores the Supreme Court, puts the public at risk, and flagrantly violates EPA’s legal responsibilities.”

 
Related

•  Read the EPA Announcement
•  E.P.A Expected to Erase Limits on Climate Pollution From Power Plants
•  EPA Proposes Removal of Carbon Dioxide Limits on Power Plants
•  The State of the Science 1 Year On: Climate Change and Energy
•  Get Involved: AGU Science Policy Action Center
 

If the Trump administration prevails, the rationale that the EPA lacks the authority to regulate emissions could make it difficult for future administrations to revisit similar regulations.

The announcement comes during a presidential term in which the Trump administration has loosened emissions regulations for other pollutants, taken action to sustain a declining coal industry, and sowed doubts about the science of climate change.

In February, the administration announced that coal-powered plants would now be able to emit more than twice as much mercury and revoked the 2009 scientific determination that provided a legal underpinning for major U.S. climate rules. The Trump administration has also ordered aging coal plants in five states to stay open, actions that have been repeatedly challenged in court.

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2026. AGU. 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 January 2025 Los Angeles wildfires, fueled by prolonged drought and extreme Santa Ana winds, rapidly spread across the region, destroying thousands of structures, causing widespread evacuations and fatalities, and becoming one of the most destructive and costly wildfire disasters in California’s history.

Rolla et al. [2026] highlight how satellite and airborne observations provided by NASA supported situational awareness throughout the disaster, even as the Eaton Fire forced the temporary closure of the Jet Propulsion Laboratory. These observations also proved essential for damage assessment, air quality monitoring, infrastructure evaluation, and debris-flow forecasting. By examining both the value of these remote sensing products and the operational challenges encountered during the Los Angeles wildfires, the study identifies priorities for improving wildfire risk mitigation. It further concludes that upcoming missions, including the NASA-ISRO Synthetic Aperture Radar (NISAR) and Surface Biology and Geology (SBG) missions, will further enhance the ability to transform Earth observations into actionable information for disaster response and management.

Eaton Fire burn severity map derived from the differenced Normalized Burn Ratio (dNBR) computed per pixel from pre-fire (September 5, 2024) and post-fire (January 16, 2025) remotely sensed observation. Colors denote estimated burn severity: green – unburned or very low change; yellow – low; orange – moderate; red – high. Credit: Rolla et al. [2026], Figure 1

Citation: Rolla, J., Miner, K., Elder, C., Howard, E., Milton, J., & Spangler, N. (2026). Remote sensing during the 2025 Los Angeles wildfires. AGU Advances, 7, e2025AV002092. https://doi.org/10.1029/2025AV002092

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

Text © 2026. The authors. CC BY-NC-ND 3.0
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Snails carry weather records on their backs that could be used to map prehistoric cyclones, a University of Queensland study has shown. The project led by School of the Environment researchers examined the rings on the shell of a Biggenden Banded Snail (Figuladra bayensis) collected from Coalstoun Lakes National Park in southeast Queensland.

Source: AGU Advances

In May 2024, Earth experienced its most intense geomagnetic storm since the Halloween storms of 2003. This “superstorm” filled night skies in many parts of the world with colorful aurorae, and it disrupted some infrastructure, such as GPS signals used by agricultural equipment.

Satellite observations revealed that during the storm, Earth’s outer Van Allen radiation belt underwent a sudden, dramatic loss of highly energetic electrons. Lyu et al. now report the first comprehensive analysis of how this rapid electron transport occurred, with key implications for future space weather forecasting.

The Van Allen radiation belts are donut-shaped rings that encircle our planet and harbor energetic electrons and protons—mostly from the solar wind—trapped by Earth’s magnetosphere. Geomagnetic storms can reconfigure the magnetosphere, causing sudden changes to electron dynamics in the outer radiation belt, which may be hazardous to satellites.

Despite decades of research on these risks, the dynamics of rapid electron transport in the radiation belts during particularly extreme storms has so far been unclear. The May 2024 superstorm presented a rare opportunity to study this phenomenon.

The researchers analyzed data from the Japan Aerospace Exploration Agency’s (JAXA) Arase satellite, quantifying the dramatic depletion of electrons from the outer radiation belt during the superstorm. To explore the physical processes behind the rapid loss, they simulated the event using the Versatile Electron Radiation Belt (VERB) model, which is designed to reproduce radiation belt dynamics.

They found that two previously studied processes were the primary drivers of the electron loss: magnetopause shadowing, which transported electrons outward and released them into space, and local wave scattering, which moved electrons inward into Earth’s upper atmosphere. The relative dominance of each process differed in different regions of Earth’s magnetic field.

Importantly, for the simulations to accurately reproduce the real-world extreme electron loss, the onset of sudden, outward electron transport associated with magnetopause shadowing had to occur nearly simultaneously with a strong compression of Earth’s magnetosphere that occurred during the superstorm. This compression was followed by local wave scattering.

Standard models of electron transport commonly used in space weather forecasting do not accurately capture the tightly coupled timing of superstorm dynamics and electron transport processes revealed in this study. The new findings could help guide development of better models, which could lead to more accurate superstorm forecasting and risk assessment. (AGU Advances, https://doi.org/10.1029/2026AV002476, 2026)

—Sarah Stanley, Science Writer

Citation: Stanley, S. (2026), How the 2024 solar superstorm drained Earth’s radiation belt, Eos, 107, https://doi.org/10.1029/2026EO260289. Published on 14 September 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.

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

In celebration of Peer Review Week 2026, American Geophysical Union (AGU) Publications recognizes 244 outstanding reviewers for their work in 2025, as selected by the editors of each journal.

Peer review—the practice of having knowledgeable, experienced colleagues provide authentic, independent, and valuable feedback on scientific manuscripts to help promote clarity and accuracy in the scientific record—is fundamental to the scientific process. This system of peer review, coupled with a culture of transparent and open data, promotes greater understanding and trust in science. Reviewers are central to a culture of shared science stewardship and are increasingly important to retain in the age of artificial intelligence (Santos et al., 2026). When there are so many formats for sharing and consuming ideas and research, a healthy and thriving system of peer review ensures that we encourage clear communication and maintain the highest integrity and trust in our scientific publications.

At AGU, the peer review process is conducted by scientists, starting with the journal editors. It is then the peer reviewers who take time away from their own research to volunteer time and expertise to help others in our scientific community improve their articles and aid publication decisions. The work of these colleagues ensures that thousands of articles each year receive independent feedback as part of a robust process of evaluation and consideration for publication. We are thankful for their efforts to make the work of our Earth and space science community better.

Peer review ensures that we encourage clear communication and maintain the highest integrity and trust in our scientific publications.

Advances in the Earth and space sciences rely on ever more complex approaches and datasets as reflected in the papers that present their results. Peer reviewers share their substantial expertise to evaluate detailed and intricate science conducted by individuals and most often teams of researchers large and small. To provide robust feedback, reviewers assess insights gleaned from studies utilizing new techniques, data, and simulations that increase in scale and scope each year. Thus, both the value and challenge of peer reviewing keeps growing. We all benefit from the practice of peer review because it sharpens the focus and increases the value and trust in the scientific work published in AGU journals.

The outstanding reviewers listed here have provided in-depth, valuable, and timely feedback and evaluations, often through multiple revisions, and multiple manuscripts, that have led to clearer and greatly improved final published papers. Their contributions helped raise the quality of submissions received from around the world, delivering valuable feedback that makes for better scientific discourse.

Many Reviewers: A Key Part of AGU Journals

In all, more than 20,000 reviewers completed 43,804 reviews in 2025.

While we recognize these few outstanding reviewers, we also acknowledge the incredible service to the community by all the researchers who have conducted reviews to help ensure the quality, timeliness, and reputation of AGU journals. We also welcome new and first-time reviewers who have joined the family of community servants who act as integrity stewards and have been providing authors with valuable feedback to improve their science and communication. In 2025, AGU received more than 24,000 submissions, which was a significant increase from 2024, and published 8,870 articles, which is an increase of more than 1,300 from the previous year. Most submissions were reviewed multiple times—in all, more than 20,000 reviewers completed 43,804 reviews in 2025.

With so many geopolitical factors shifting around the globe, having robust international representation among peer reviewers and editors is increasing in importance. And the challenges of maintaining the peer review system remain elevated. Volunteer reviewers in Europe and the United States receive more invitations than they can accept, while research output in China is now the highest of any country. AGU journals continue to make progress in balancing the efforts of colleagues serving our community via conducting peer reviews even as they often struggle to invite a proportional number of reviewers across the globe. Likewise, early career researchers request training and seek opportunities to enter the peer review system. AGU is committed to building further entrance points to peer reviewing including its co-reviewing program and early career editorial training programs in individual journals.

Amidst these challenges, each AGU journal works to maintain low time frames from submission to first decision and publication, and consistently maintains industry-leading standards. Reviewers play a central role in the rapid feedback and publishing of new science that is at the heart of advancing the Earth and space sciences.

Editorials in each journal express our appreciation, along with reviewer recognition lists. Our thanks are a small acknowledgment of the large service that reviewers bear in improving our science and its role in society.

Additional Thanks

In addition, we are working to highlight the valuable role of reviewers through events at AGU’s Annual Meeting and other meetings.

We will continue to work with the Open Researcher and Contributor ID (ORCID) network to provide official recognition of reviewers’ efforts, so that reviewers receive formal credit there. In 2025, 6,286 of the more than 20,000 reviewers linked their review activity to their ORCID, taking the opportunity to receive formal recognition for their peer review efforts. Separately, as of July 7, 2026, 132,522 users in our system have an ORCID associated with their account.

Getting Your Feedback

We value your feedback, including ideas about how we can recognize your efforts even more, improve your experience, and increase your input into the science. Feel free to send your comments to publications@agu.org. We look forward to hearing from you!

Once again: Thanks to our Outstanding Reviewers of 2025!

—Matt Giampoala (mgiampoala@agu.org, 0000-0002-0208-2738), Vice President, Publications, American Geophysical Union; and Steven A. Hauck II (0000-0001-8245-146X), Chair, AGU Publications Committee

Citation: Giampoala, M., and S. A. Hauck II (2026), In appreciation of AGU’s outstanding reviewers of 2025, Eos, 107, https://doi.org/10.1029/2026EO265037. Published on 14 September 2026. 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 © 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.

A guest post by Serge Leroueil and Luciano Picarelli

A new book, Understanding Landslides Through Case Studies by Serge Leroueil and Luciano Picarelli seeks to report and summarise contemporary knowledge on slope movements and mechanisms.

As is well-known on this Blog, landslides are a major natural hazard in many countries of the world. The annual loss of human lives and the damage to structures and infrastructure is severe, and in many cases is higher than those caused by other natural hazards. Since extreme weather events are a major trigger, in the near future climate change will play a key role whose impact cannot be fully predicted today.

A new book, Understanding Landslides Through Case Studies that we have written and edited seeks to report and summarise contemporary knowledge on slope movements and mechanisms, putting experience in the centre. To this end the authors/editors have involved a number of renowned experts in the domains of geotechnical engineering and geology, asking them to bring their own experience and ideas to highlight specific aspects. The book mostly focuses on landslides in soils.

Understanding Landslides Through Case Studies

This book, which is particularly suitable for graduate students, researchers and professionals, consists of two parts. The first part summarises the present knowledge, from the pre-failure to the post-failure stage including landslide reactivation and active slope movements. The second part is a collection of 28 papers written by experts from all over the world reporting and interpreting specific case studies.

The first part of the book consists of the following six chapters that frame the problem touching the main causes of slope movement, the mechanisms and the mechanics of slope failure and of post-failure landslide evolution, and thus the basic types of movement (classification):

Chapter 1. Slope formation from a geotechnical perspective. This chapter discusses the formation and the evolution of slopes in different geological and climatic contexts.

Chapter 2. Slope movements. It examines in detail the mechanical aspects of slope failure from the pre-failure to the post-failure stage and the modes of landslide formation and evolution. The updated version of the Varnes classification (Hungr et al. 2014) is the basis for description of landslide evolution and thus of the mechanics of slope movements that is behind.

Chapter 3. Behaviour and properties of soils in the context of slopes. An in depth discussion about the hydraulic and mechanical properties of both saturated and unsaturated soils is the starting point of Chapter 3. Key parameters that govern soil behaviour including some often disregarded factors such as time, temperature, fluid chemistry and even gas that may be present are examined in detail.

Chapter 4. Slope movements induced by changes in boundary stress conditions. Besides the effects of well-known static and dynamic loading and unloading processes, the possible consequences of phenomena and processes such as rapid drawdown, storm waves, blasting and pile driving are also considered.

Chapter 5. Slope movements induced by changes in hydraulic or physico-thermo-chemical conditions. This chapter examines the effects of infiltration and evapo-transpiration, of soil deterioration, of thermal effects and of the presence of gas, free, dissolved or in the form of hydrate.

Chapter 6. From pre-failure to post-failure (including reactivation). A room is finally given to macroscopic landslide mechanisms, and thus types of movement (classification), which affect landslide analysis. Special movements such as flowslides in sensitive clays and earthflows (often mudslides in the British literature) are also described in this chapter.

As mentioned above, the second part of the book presents a number of case studies from all over the world, illustrating mechanisms described in the first part and providing a panorama of situations whose knowledge may be a useful reference for readers. The examined cases form six chapters following the same rationale as the book.

Chapter 7. Hydro-mechanical pre-failure processes

• 7.1 Introduction
• 7.2 The Saint-Hilaire Case Study by J. Lafleur, S. Leroueil & J.-F. Laflamme
• 7.3 The London Heathrow Airport’s Terminal 5 Case Study by D.W. Hight, N. Kovacevic & D.M. Potts
• 7.4 The Bukit Batok Case Study by H. Rahardjo, E.C. Leong & R.B. Rezaur
• 7.5 The Lavini di Marco Case Study by P. Tommasi, L. Verrucci & P. Campedel
• 7.6 The Randa Case Study by E. Eberhardt, H. Willenberg, S. Loew & D. Stead
• 7.7 Concluding remarks

Chapter 8. First-time landslides

• 8.1 Introduction
• 8.2 The Warden Point Case Study by E.N. Bromhead & N. Dixon
• 8.3 The Aznalcollar Case Study by A. Gens & E.E. Alonso
• 8.4 The Saint-Liguori Case Study by S. Leroueil, L. Ouehb, D. Demers, G. Grondin & J. Locat
• 8.5 The Baie-des-Anges Case Study by S. Garziglia, N. Sultan, S. Stegmann & A. Kopf
• 8.6 The Três Barras Case Study by W. A. Lacerda, A.P. Fonseca Becker, L. De Bona Becker & A.L. Coelho Netto
• 8.7 Case studies in Chinese loess deposits by Z. Lin & Z. Xu
• 8.8 Concluding remarks

Chapter 9. Active and reactivated landslides

• 9.1 Introduction
• 9.2 The Sallèdes Case Study by P. Pouget
• 9.3 The Vallcebre Case Study by J. Corominas, A. Ledesma, J. Moya, D.A. Gonzàlez, J.A. Gili, A. LLoret & M. Hürlimann
• 9.4 The Cortes de Pallas Case Study by N.M. Pinyol, E.E. Alonso & M. Maglia
• 9.5 The Rosone Case Study by M. Castelli & C. Scavia
• 9.6 The Clapière Case Study by J.-L. Durville, J.-L. Perez & J.-F. Serratrice
• 9.7 Concluding remarks

Ch. 10. Flow-like landslides in cohesive soils

• 10.1 Introduction
• 10.2 The Masseria Marino Case Study by L. Picarelli, L. Comegna & G. Urciuoli
• 10.3 The Super-Sauze Case Study by J.-P. Malet, O. Maquaire, Th.W.J. van Asch & T.A. Bogaard
• 10.4 The Saint-Jean-Vianney Case Study by J. Potvin, D. Demers, D. Robitaille & S. Leroueil
• 10.5 The Pointe-du-Fort Case Study by J. Locat, P. Locat, S. Leroueil & A. Locat
• 10.6 The Storegga Case Study by F. Nadim & T.J. Kvalstad
• 10.7 Concluding remarks

Ch. 11. Flow-like landslides in cohesionless soils

• 11.1 Introduction
• 11.2 The Cervinara Case Study by L. Olivares, E. Damiano & L. Picarelli
• 11.3 The Sau Mau Ping Case Study by K.K.S. Ho & H.W. Sun
• 11.4 The Aberfan Case Study by H.J. Siddle & J.N. Hutchinson
• 11.5 The Charles Creek Case Study by O. Hungr & P. Wilson
• 11.6 Concluding remarks

Ch. 12. Spreads

• 12.1 Introduction
• 12.2 The Bisaccia Case Study by L. Picarelli, L. Olivares, G. Urciuoli & F. Silvestri
• 12.3 The Thompson River Valley at Ashcroft Case Study by A. Eshraghian, C.D. Martin & N.R. Morgenstern
• 12.4 The Saint-Barnabé Case Study by A. Locat, S. Leroueil, D. Demers & J. Locat
• 12.5 Concluding remarks

Reference

Hungr, O., Leroueil, S. & Picarelli, L. 2014. Varnes classification of landslide types, an update. Landslides, 11(2), 167-194.

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AbstractTomographic reconstruction involves fundamental trade-offs between resolution, data coverage, and parameterisation. Conventional approaches commonly rely on regularised pixel-wise or cell-based parameterisations. These regularisations are valuable and can themselves be geology-informed when their assumptions match the target setting. However, they often encode structural information only indirectly through generic penalty terms and regularisation weights. As a result, they can be less suited to questions in which the objective is to test a specific structural hypothesis. We develop a Bayesian framework for tomographic reconstruction and uncertainty quantification that formulates such hypotheses explicitly and assesses them through posterior uncertainty. As an illustrative application of the framework, we consider ambient noise tomography. The phase velocity reconstruction is reformulated to address a targeted geological hypothesis by introducing a parameterised structural prior. The prior is constructed from a Whittle–Matérn latent Gaussian field, combined with spectral dimensional reduction via a truncated Karhunen–Loève expansion and a differentiable nonlinear pushforward mapping that promotes approximately piecewise-constant velocity structures. The prior parameters, including the correlation length, smoothness, pushforward slope, and velocity bounds, provide interpretable hyperparameters related to expected lateral scale, structural regularity, transition sharpness, and plausible phase-velocity contrasts. In this formulation, the prior is used as a parameterised structural assumption informed by geological context, rather than as hard geological knowledge. The resulting parameterisation substantially reduces dimensionality, making both maximum a posteriori estimation and Hamiltonian Monte Carlo sampling computationally feasible for the synthetic and observed datasets considered here. Synthetic experiments demonstrate accurate recovery of prescribed velocity contrasts and show that posterior uncertainty patterns reflect acquisition geometry and data coverage. Application to a ∼1000-sensor dense array dataset produces structures consistent with the imposed geology-informed prior assumptions, while providing spatially resolved uncertainty estimates that identify regions of robust inference and remaining ambiguity. The framework offers a proof-of-concept formulation for goal-oriented, uncertainty-aware seismic tomography when prior information supports an explicit structural hypothesis that can be encoded through the proposed Whittle–Matérn latent-field parameterisation.

Plans to limit the global temperature rise to 1.5°C above preindustrial levels depend on reaching net-zero emissions and, in many cases, actively removing carbon dioxide (CO2) from the air. While this helps limit extreme weather, sea level rise, ecosystem loss and the risk of triggering irreversible climate tipping points, a new study, published in Science Advances, finds that reducing CO2 levels may have an unexpected effect. Climate simulations used in the study suggest that the Southern Ocean around Antarctica may switch from being an important carbon sink to being a prolific source of carbon.

SummarySubterranean rock masses are in true triaxial stress (TTS) fields, which can preferentially close internal microcracks, thereby inducing elastic anisotropy. However, the seismic response under TTS is poorly understood. Here, an analytical PP-wave reflection coefficient for triaxial stress-induced anisotropic media modelled by microcrack closure mechanism is proposed for seismic inversion. Considering a micromechanical model in which microcracks are represented by stress-dependent compliances, the stress magnitude and orientation are firstly incorporated to account for the elastic anisotropy resulting from triaxial stress-induced microcrack closure. A good agreement is obtained between the model predictions and the existing laboratory measurements. Based on weak anisotropy assumption, we then deduce the effective stiffness tensor of the triaxial stress-induced anisotropic media. Three sets of stress-related anisotropy indicators (SRAIs) are introduced to quantify the microcrack closure effect and anisotropy magnitude induced by triaxial stress. Furthermore, a linearized PP-wave reflection coefficient equation for triaxially stressed isotropic media is derived using the scattering theory. Numerical results validate the feasibility and accuracy of the proposed formula, and reveal the influence of TTS on the PP-wave amplitude variation with angle and azimuth (AVAz). Finally, due to the highly ill-conditioned AVAz inverse problem in triaxial stress-induced anisotropic media, a model and data driven inversion approach is proposed through building on a convolutional neural network. We stepwise estimate the isotropic elastic parameters and SRAIs based on azimuthal seismic amplitude difference inversion strategy. Tests on both synthetic and real seismic data indicate that the nonlinear AVAz inversion framework outperforms conventional approaches in terms of stability and accuracy. Our study allows the construction of elastic properties in triaxial stress-induced anisotropic media, and may provide new insights into determining in-situ stress from seismic data.

SummaryBy leveraging a significantly expanded GNSS dataset (997 vectors, 335 new), we construct a high-resolution crustal strain rate model for the Southeastern Tibetan Plateau (SETP) that approximately doubles the resolution of previous studies. Our model delineates a prominent J-shaped high-strain zone that follows the Xianshuihe-Xiaojiang fault system (XXFS) and extends ∼600 km southwestward. This feature, combined with unsupervised Euler pole clustering (EPC) machine learning results, provides further evidence for a mid-to-lower crustal linkage between the XXFS and faults southwest of the Red River fault (RRF), suggesting the active XXFS is propagating across this ancient boundary (RRF) at depth. Within the SETP interior, our model reveals widespread extensional deformation characterized by a systematic clockwise rotation of its principal axes from north to south, alongside discrete rotational domains partitioned by major faults. Shear strain patterns within the SETP indicate that major strike-slip faults, predominantly sinistral, drive regional strain localization. Moreover, the close association between modeled high-strain zones and historical M ≥ 6 earthquakes suggests that our high-resolution model can serve as a refined, physically-based perspective for regional seismic hazard assessment.

SummaryWhile Bayesian inference is widely applied to magnetotelluric, seismic, and magnetic datasets, its application to gravity anomalies remains relatively unexplored. To address this, we introduce InDIA (Inversion of Density Interface and its Application), a Python-based Bayesian inference framework utilizing a structural Gaussian process. InDIA is developed to estimate discretized subsurface layer depths and densities while explicitly quantifying uncertainty. Unlike previous techniques restricted to continuous depth profiles and localized issues, InDIA integrates diverse prior information to effectively resolve both local and regional gravity anomalies. This approach successfully mitigates the multi-parameter challenges and convergence issues common in local gradient-based optimization techniques, such as Adam. The superiority of this algorithm has been validated through various synthetic models (involving multi-prism configurations, two-layer models with lateral density variations, heterogenous subsurface model with lateral and vertical density variation along with faulted dipping models) featuring both constant and variable density distributions—whether lateral, vertical (prior-constrained), or both—incorporating Gaussian noise, Random-walk noise, Systematic noise and Salt and Pepper noise to replicate real conditions. Furthermore, the framework’s field applicability is demonstrated using two real gravity datasets. First, it tackles multi-layered subsurface profiling in the West Korea Basin. Second, it simultaneously resolves depth and prior-constrained vertical density variations in the Godavari Basin, India. In both field applications, the inverted parameters are geologically viable and closely align with previously established models, confirming InDIA as a reliable tool for gravity data inversion.

Loose fibers from functional clothing, discarded PET bottles or abandoned packaging: When such plastic materials enter the environment, they often persist there for a long time. UV radiation, precipitation and ozone cause them to become brittle—and over time, mechanical forces break them down into increasingly smaller particles. Swirled up by the wind, they are carried farther through the atmosphere. Until now, it was unclear how much microplastic ends up back in Swiss soil and water bodies through this process.

When will the glacier in your valley disappear? Will the glacier you visited as a child still exist in 2050? And how much difference would limiting global warming make?