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Thicker sediments under Salt Lake could result in more intense ground shaking

Phys.org: Earth science - Wed, 06/04/2025 - 11:11
The sediments underlying the Salt Lake Valley are thicker in places than previously thought, indicating that current seismic hazard models likely underestimate the amount of shaking Utah's population center could experience in future earthquakes, according to new research led by University of Utah seismologists.

Generation and transport of fast electrons under a nonuniform magnetic field produced by a coil target

Physical Review E (Plasma physics) - Wed, 06/04/2025 - 10:00

Author(s): Zhi-Wei Wang, Tie-Huai Zhang, and Wei-Min Wang

We investigate with particle-in-cell simulation the transport of fast electrons of MeV under a kT-level magnetic field produced by a circular coil target, where the fast electrons are generated by a picosecond laser pulse with typical intensity of 5×1019W/cm2 adopted in fast ignition. The fast elect…


[Phys. Rev. E 111, 065204] Published Wed Jun 04, 2025

Ban high-seas fishing, mining 'forever': Experts

Phys.org: Earth science - Wed, 06/04/2025 - 09:00
Governments should ban all mining and fishing in the high seas "forever" to protect ocean biodiversity, climate stability—and humanity, climate and ocean experts said Wednesday.

The 1 June 2025 landslide at Muta township in Tibet

EOS - Wed, 06/04/2025 - 06:09
What’s Next for Science? .wp-block-newspack-blocks-homepage-articles article .entry-title { font-size: 1.2em; } .wp-block-newspack-blocks-homepage-articles .entry-meta { display: flex; flex-wrap: wrap; align-items: center; margin-top: 0.5em; } .wp-block-newspack-blocks-homepage-articles article .entry-meta { font-size: 0.8em; } .wp-block-newspack-blocks-homepage-articles article .avatar { height: 25px; width: 25px; } .wp-block-newspack-blocks-homepage-articles .post-thumbnail{ margin: 0; margin-bottom: 0.25em; } .wp-block-newspack-blocks-homepage-articles .post-thumbnail img { height: auto; width: 100%; } .wp-block-newspack-blocks-homepage-articles .post-thumbnail figcaption { margin-bottom: 0.5em; } .wp-block-newspack-blocks-homepage-articles p { margin: 0.5em 0; } Can the Belt and Road Go Green? Crafting Signs for Geoscience’s Future The Arctic’s Uncertain Future Empowering Genderqueer Geoscientists: Being and Building the Change New Map Reveals the Extent of Vegetation in Antarctica What’s Next for Science? Look in the Mirror

A 200,000 cubic metre rockslide in a remote area of Tibet on Sunday has left ten people dead or missing.

On 1 June 2025 a large rockslide occurred in Muta township in Chamdo (Qamdo) metropolitan area in Tibet. Note that Chinese media sources call this area Xizang Autonomous Region, but it is what most of us know as Tibet. Chinese media reports, which can be unreliable from Tibet, indicate that three people are confirmed to have been killed with a further seven reported to be missing. Two people were injured.

CGTN has a video online showing the landslide, which includes drone footage. The area has a dusting of snow, which makes interpretation difficult. CCTV also has the same footage posted to Youtube:-

This video includes imagery of the head scarp of the landslide:-

The head scarp of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

There is also a good image of the full length of the rockslide:-

The full extent of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

This landslide has a slightly unusual morphology, with much of the material from the upper portion of the slope stalled on the hillside. However, the mass of material in the valley floor is large, as this image shows:-

The lower portion of the 1 June 2025 rockslide at Muta in Tibet. Image from a video posted to Youtube by CCTV.

The landslide has blocked the valley and a small lake has started to develop. This will need to be managed. Note the run up of the landslide deposit on the opposite slope, which indicates that the mass was moving comparatively quickly. There are two people on the left of the image for scale.

The CGTN video suggests that the landslide was about 200,000 m3, which would be around 500,000 tonnes.

The precise location of this event is unclear to me. Chamdo is a large area centred on [31.1362, 97.2359]. A report by Xinhua suggests that the landslide occurred in Dengqen County (Dêngqên County), which is in the northwest of Chamdo, centred on [31.5396, 95.4156]. Wikidata indicates that Muta is located at [32.30957, 95.09376], and Google maps has this location as “Mutaxiang”, with “Muta town” a little to the west, so this is credible. We shall have to wait for a clear day to obtain satellite imagery to confirm this – given the limited loss of life, the landslide has probably not struck Muta itself.

As usual for China, especially when it comes to Tibet, the media footage includes lots of images of the response of the authorities to the disaster. Sadly, the likelihood of the missing people being recovered alive is very low.

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.

Imaging the seismic structure of the western Makran Subduction Zone

Geophysical Journal International - Wed, 06/04/2025 - 00:00
SummaryWe analyze data from 48 seismic stations located in the western part of the Makran Subduction Zone to gain a detailed knowledge of the crustal and uppermost mantle structure in that region. The Makran is a flat subduction zone with a very thick accretionary wedge. It is a major tsunami hazard of the Indian Ocean but remains one of the world's least studied subduction zones. Its structure and evolution is increasingly becoming a subject of research interest as it can help to better understand the dynamics of flat subduction zones. Our P- and S-wave receiver function analyses reveal that the Arabian oceanic plate is currently dipping north-ward beneath the onshore accretionary wedge at a very low angle of 3°. The depth of the oceanic Moho in the coastal region is ∼30 km due to the presence of ∼22-24 km of sedimentary cover. It increases to ∼60 km beneath the Jazmurian Depression and further deepens to ∼80 km beneath the Bazman and Taftan volcanoes. The change from a relatively flat to a steeper subduction occurs just south of the Qasr-e Qand thrust fault. From the combined results of the receiver function stacking and joint inversion of P-wave receiver functions and Rayleigh wave group dispersion data, we infer that the continental Moho varies within a depth range of 40 to 56 km, with the shallowest part beneath the Sistan Suture Zone and the deepest beneath the Taftan volcano. Based on shear-wave velocity models, the sedimentary cover thickness in the onshore accretionary wedge varies from Coastal Makran to 34 km in Inner Makran. The lower-than-normal mantle wedge shear-wave velocities suggest that the mantle wedge might have undergone at least 25 per cent serpentinization. From the velocity models we conclude that the crust of the Jazmurian Depression is more likely of continental origin.

Impact of geodetic information, subduction zone segmentation, and slow-slip events in probabilistic seismic hazard: A case study for Costa Rica

Geophysical Journal International - Wed, 06/04/2025 - 00:00
AbstractA Slow-Slip Event (SSE) is a slow release of tectonic stress along a fault zone, over periods ranging from hours to months. SSEs have been recorded in most of the geodetically well-instrumented subduction zones. Although these transient events observed by geodesy are typically excluded from probabilistic seismic hazard analysis (PSHA), they might play a crucial role in the seismic cycle by reducing the seismic slip rate (slip rate discounting the aseismic process). This effective reduction implies that incorporating SSEs into PSHA may improve the reliability of hazard assessments. Costa Rica, located at the southern end of the Middle American Trench, hosts large earthquakes as well as SSEs. Shallow and deep SSEs have long been detected at the Nicoya peninsula, in northern Costa Rica, and recently, also in the southern part of the country at the Osa peninsula. In this study, we first collect geodetic and SSE observations in Costa Rica. Then, we propose a method to incorporate them into PSHA, based on identifying regions where SSEs occur, inferring slip deficits and estimating seismic slip rates in each subduction segment. Next, we analyze the implications for PSHA and its epistemic uncertainty, using these seismic slip rates, the resulting seismic moment rate budgets, and determining earthquake rates and maximum magnitudes with different approaches. Finally, we compute a countrywide PSHA following the 2022 Costa Rica Seismic Hazard Model (CRSHM 2022) but modifying the seismic source characterization using geodetic information for the regions where SSEs occur. Compared to the CRSHM 2022, this approach leads to reductions of the resulting peak ground acceleration at return period of 475 years (PGA-475) of up to ∼15 per cent in the Nicoya peninsula, but also to an increase up to ∼40 per cent in the Central Pacific region and ∼30 per cent in the Osa peninsula. Moreover, we find that, under a geodetic-based approach and disregarding SSEs, the PGA-475 would increase by up to ∼10 per cent. Our novel approach underscores the relevance of incorporating geodetic observations and particularly SSEs into PSHA, especially in subduction margins near the coast.

Five geoengineering trials the UK is funding to combat global warming

Phys.org: Earth science - Tue, 06/03/2025 - 16:22
The UK government recently announced plans to fund five small-scale trials related to geoengineering. It's the first time a state research funding body has put serious money into what's known as solar radiation management, or SRM, which seeks to cool the planet by reflecting more of the sun's energy back into space.

Scientists say next few years vital to securing the future of the West Antarctic Ice Sheet

Phys.org: Earth science - Tue, 06/03/2025 - 15:12
Collapse of the West Antarctic Ice Sheet could be triggered by very little ocean warming above present-day, leading to a devastating four meters of global sea level rise to play out over hundreds of years, according to a study now published in Communications Earth & Environment, co-authored by the Potsdam Institute for Climate Impact Research (PIK). However, the authors emphasize that immediate actions to reduce emissions could still avoid a catastrophic outcome.

What made Mount Etna's latest eruption so rare

Phys.org: Earth science - Tue, 06/03/2025 - 15:10
Mount Etna, the volcano that towers over eastern Sicily, has again captivated the world with a spectacular show, spewing smoke and high into the sky.

Simulation shows how declines in coral reef calcification could affect future ocean carbon sink capabilities

Phys.org: Earth science - Tue, 06/03/2025 - 14:46
A team of meteorologists, Earth scientists and oceanographers at Sorbonne Université, working with one colleague from Université Paris-Saclay and another from Université Brest, all in France, has developed a simulation that they believe shows how declining coral reef calcification could slow global warming.

Is Your Shampoo Washing Up in Antarctica?

EOS - Tue, 06/03/2025 - 13:36

Antarctica is Earth’s most remote continent, barely touched by human activities.

It is, however, not immune to the kind of environmental damage that plagues more populated parts of the world. In a new study, researchers found chemicals originating from everyday personal care products (PCPs), such as cosmetics, detergents, pharmaceuticals, and deodorants, in Antarctic snow.

Contaminants in PCPs—loosely defined as semivolatile organic compounds that are industrially produced at a global scale, used in large volumes, and relatively persistent in the environment—are increasingly being recognized as pollutants. Both the Arctic Monitoring and Assessment Programme and the Scientific Committee on Antarctic Research have encouraged further research on PCP ingredients and the creation of monitoring plans for tracking their presence at the poles.

Looking for these pollutants, researchers collected 23 surface snow samples from 18 sites along the Ross Sea coast during the Antarctic summer of 2021–2022. Though some sampling locations were near areas with human activity, including Italy’s seasonally occupied Mario Zucchelli research station, the majority were situated hundreds of kilometers from human settlements.

The scientists reached these remote locations by piggybacking on helicopter rides transporting other teams maintaining weather stations or deploying scientific instruments. “This way we halved the impact of our sampling, because they needed to go there in any case,” said Marco Vecchiato, an analytical chemist at Ca’ Foscari University in Venice, Italy, who led the study.

Back in Italy, Vecchiato and his colleagues analyzed the snow samples under clean-room conditions to prevent contamination.

“This very different behavior during the season means that [PCPs] are very sensitive to the environmental conditions.”

They found PCP chemicals in every sample, with varying chemical concentrations suggesting different capacities for atmospheric transport. Of the 21 chemicals analyzed, three compound families were particularly notable. Salicylates, commonly used as preservatives in cosmetics (including lotions, shampoos, and conditioners) and pharmaceutical products, were the most prevalent, followed by UV filters associated with sunscreens. Fragrances such as musks were also detected.

Most of these substances were dissolved in the snow. The UV filter octocrylene, however, which has been associated with coral reef damage and banned in places like the U.S. Virgin Islands and Palau, was found bound to solid particles within the snow.

The researchers observed an unexpected seasonal variation in the amount of PCPs within the samples: Samples collected later in the summer had about 10 times higher PCP levels than those collected earlier in the season, though the relative proportions of each pollutant within a sample remained consistent.

Seasonal fluctuation suggests that Antarctic summer air circulation plays a role in transporting pollutants from distant sources to the continent’s interior. During summer, oceanic winds blowing inland dominate over winds originating from the polar plateau, which are stronger during the rest of the year. That shift may push pollutants far inland.

“This very different behavior during the season means that [PCPs] are very sensitive to the environmental conditions,” Vecchiato said.

One of the researchers presented the team’s preliminary findings at the European Geosciences Union General Assembly in May, and the scientists have a more comprehensive analysis currently underway, according to Vecchiato.

A Local or Distant Source

Finding organic pollutants in seemingly pristine polar environments isn’t surprising. In the 1960s, scientists found large concentrations of persistent organic pollutants (POPs), including the widely used pesticide DDT (dichlorodiphenyltrichloroethane), in Antarctica. POPs don’t degrade naturally and travel thousands of kilometers through the atmosphere, with some eventually getting trapped in snow and ice. Permanently frozen places such as glaciers and polar regions become natural traps. Starting in the early 2000s, the United Nations’ Stockholm Convention on Persistent Organic Pollutants established international cooperative efforts to eliminate or restrict the production and use of POPs.

Though they might travel by a mechanism similar to that used by persistent organic pollutants, unlike POPs, PCPs “do break down in the environment,” said Alan Kolok, a professor of ecotoxicology at the University of Idaho. However, “if those fragrances are not coming from the [research] stations themselves,” he asked, “where are they coming from?”

“Thousands of people are currently accessing the Antarctic continent, and my conclusion is that wherever we humans go, we bring contaminants.”

To rule out a local origin for the PCP pollutants, researchers analyzed sewage from the Mario Zucchelli research station. The outpost did contribute some pollution, but the relative abundance of each compound in the sewage differed from that found in the snow, suggesting that the PCPs detected in the broader Antarctic environment likely originated from more distant sources.

“My suspicion is that for these types of compounds—personal care products, pharmaceutical products—there must be a local source,” said Ricardo Barra Ríos, an environmental scientist at the Universidad de Concepción in Chile who has analyzed PCP pollution in Antarctic coastal waters related to research stations. “Thousands of people are currently accessing the Antarctic continent, and my conclusion is that wherever we humans go, we bring contaminants.”

Vecchiato disagreed. In a separate study published earlier this year, he and other colleagues found PCPs, including fragrances and UV filters, in the snows of the Svalbard archipelago in the Arctic. In that study, the researchers linked the presence of these compounds to atmospheric patterns that carried pollution from northern Europe and the northwestern coast of Russia.

“Most of these contaminants should have a limited mobility, but actually, we found them in remote regions,” Vecchiato said. “Does that mean that the models are wrong or that our analysis is wrong?” he asked. “No, probably we are missing a piece [of the puzzle], or maybe the use of these contaminants is so huge that we still have a relevant concentration in remote areas, even if they should not be prone to this kind of transport.”

—Javier Barbuzano (@javibar.bsky.social), Science Writer

Citation: Barbuzano, J. (2025), Is your shampoo washing up in Antarctica?, Eos, 106, https://doi.org/10.1029/2025EO250209. Published on 3 June 2025. Text © 2025. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Los ríos de Brasil se están infiltrando

EOS - Tue, 06/03/2025 - 13:30

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

En 2017, Paulo Tarso Oliveira, profesor de hidrología en la Universidad de São Paulo, se encontró con una noticia sobre una pequeña aldea a orillas del río São Francisco, uno de los principales ríos del noreste de Brasil. El artículo informaba que los habitantes estaban presentando tasas inusualmente altas de hipertensión arterial, y relacionaba esta anomalía con el clima seco de la región y el bajo caudal del río. A medida que el nivel freático descendía, el agua oceánica comenzaba a infiltrarse hacia el agua subterránea de la región, elevando los niveles de sal en el suministro y provocando problemas de salud entre la población.

“Muchas veces, la gente no se da cuenta, pero las aguas superficiales y subterráneas están conectadas y deben considerarse como un todo”.

Intrigado, Oliveira investigó más a fondo. Más adelante descubrió que el flujo del río estaba disminuyendo porque los pozos estaban extrayendo agua del acuífero subyacente. “Muchas veces, la gente no se da cuenta, pero las aguas superficiales y subterráneas están conectadas y deben considerarse como un todo”, señaló Oliveira.

En lugares donde el nivel freático se encuentra bajo el lecho de un río, el río puede filtrar agua hacia el acuífero subyacente. Este proceso, conocido como filtración del caudal fluvial, ocurre de forma natural dependiendo de las formaciones geológicas subyacentes y los niveles de agua subterránea. Sin embargo, la construcción de pozos que extraen agua en exceso de los acuíferos puede intensificar este fenómeno.

Oliveira y sus colegas descubrieron que la situación en la cuenca del São Francisco no es un caso aislado. Al evaluar pozos en todo Brasil, los investigadores encontraron que en más de la mitad de ellos el nivel del agua estaba por debajo del nivel de los arroyos cercanos.

Mapeo de pozos

En 2023, Oliveira y el estudiante de maestría José Gescilam Uchôa comenzaron a mapear los ríos de Brasil para identificar zonas en riesgo de pérdida de agua. Se basaron en datos públicos sobre niveles de ríos y ubicación de pozos, proporcionados por el Servicio Geológico de Brasil. Sin embargo, la mayoría de los pozos registrados carecían de información suficiente. Como resultado, se enfocaron en 18,000 pozos con datos completos, distribuidos a lo largo de miles de ríos en el país.

Los investigadores compararon el nivel del agua en cada pozo con la elevación del arroyo más cercano. En el 55 % de los casos, el nivel del agua en los pozos era inferior a la elevación de los arroyos vecinos.

José Uchôa realiza mediciones en un río de São Paulo. Crédito: Laboratorio de Hidráulica Computacional, Universidad de São Paulo

“Nuestros datos sugieren que el uso de aguas subterráneas está afectando significativamente el caudal de los ríos”, señaló Uchôa. “Este es, y seguirá siendo, un motivo de creciente preocupación para la gestión del agua en el país”.

El estudio, publicado en Nature Communications, también identificó regiones críticas, incluida la cuenca del São Francisco, donde más del 60 % de los ríos podrían estar perdiendo agua debido a la intensa extracción subterránea. Esta extracción se asocia principalmente con actividades de irrigación.

En la cuenca del Verde Grande, en el este de Brasil, donde la irrigación representa el 90 % del consumo de agua, el 74 % de los ríos podrían estar perdiendo agua hacia los acuíferos.

Oliveira considera que los resultados son conservadores y que la situación podría ser aún peor, ya que los investigadores no tomaron en cuenta los pozos ilegales. Un estudio realizado en 2021 por el geólogo Ricardo Hirata, de la Universidad de São Paulo, estimó que alrededor del 88 % de los 2.5 millones de pozos en Brasil son ilegales, al carecer de licencia o registro para operar.

Hirata, quien no participó en la nueva investigación, advirtió que el estudio se basó únicamente en el 5 % de los pozos existentes, ubicados principalmente en regiones donde la explotación de aguas subterráneas es más intensa.

“Quizá esto también esté ocurriendo en otras regiones del país con alta demanda de irrigación, y simplemente no lo sabemos por falta de datos”.

Hirata también subrayó que, aunque los investigadores identificaron ríos que potencialmente están perdiendo agua hacia los acuíferos, esos datos por sí solos no son suficientes para determinar si los ríos realmente se están secando. Para evaluar eso, se deben considerar otros factores, como la cantidad de agua extraída del acuífero en comparación con el caudal del río, el grado de conexión entre el acuífero y el río, y cuánta agua se extrae del acuífero en relación con las variaciones estacionales del caudal.

“El hecho de que el nivel de agua de un pozo esté por debajo del de un río cercano no necesariamente afecta al río o al acuífero”, explicó Hirata.

Las áreas identificadas como críticas por el estudio se ubican principalmente en regiones áridas, donde ya se esperaba que ocurriera filtración del caudal de manera natural, señaló André F. Rodrigues, hidrólogo de la Universidad Federal de Minas Gerais, quien no participó en la investigación.

El estudio es relevante porque resalta un problema creciente, dijo Rodrigues, pero se necesitan análisis más locales para obtener una imagen más detallada del problema y considerar, por ejemplo, los efectos del clima y los cambios estacionales. “Quizá esto también esté ocurriendo en otras regiones del país con alta demanda de irrigación, y simplemente no lo sabemos por falta de datos”, comentó.

Un problema en crecimiento

La expansión descontrolada de pozos y la extracción excesiva de agua subterránea no solo afectan la salud de las personas, el abastecimiento de agua y la agricultura, sino que también pueden desestabilizar el suelo, provocando hundimientos (subsistencia). Fenómenos similares se han observado en regiones de China, Estados Unidos e Irán.

El panorama no es nada alentador para Brasil. Es probable que la cantidad de pozos se multiplique, ya que se espera que las áreas de riego se incrementen en más del 50 % en los próximos 20 años, según la agencia nacional del agua de Brasil.

“Probablemente veremos un círculo vicioso de degradación, en el que la disminución en la cantidad y calidad del agua superficial, combinada con el aumento de los períodos de sequía, obligará a los agricultores a perforar más pozos para mantener la producción de alimentos, intensificando aún más la extracción de aguas subterráneas y agravando el problema”, advirtió Oliveira.

La sobreexplotación de aguas subterráneas es una preocupación a nivel mundial. La mayoría de los acuíferos han mostrado un descenso en lo que va del siglo XXI, y los estudios por modelado sugieren que la filtración de caudales será más común en las próximas décadas. Aun así, este problema ha sido en gran medida ignorado en regiones tropicales como Brasil, que alberga el 12 % de los recursos de agua dulce renovables del planeta.

Esta falta de atención se debe en parte al escaso financiamiento y vigilancia, y en parte a una creencia persistente de que en los países tropicales y húmedos los ríos suelen ganar agua de los acuíferos y no perderla, mencionó Oliveira. “Debemos actuar ahora si queremos evitar que regiones enteras queden devastadas en el futuro”.

Los investigadores hacen un llamado a realizar más estudios y establecer un monitoreo sistemático de los pozos para identificar las zonas más secas y evaluar el impacto de nuevos pozos sobre los ríos. Actualmente, Brasil solo cuenta con 500 pozos de observación monitoreados constantemente por el gobierno, en comparación con los 18,000 que existen en Estados Unidos, a pesar de que ambos países tienen extensiones territoriales similares. “La vigilancia es extremadamente importante y está tremendamente subestimada”, enfatizó Uchôa.

—Sofia Moutinho (@sofiamoutinho.bsky.social), Escritora de ciencia

This translation by Saúl A. Villafañe-Barajas (@villafanne) was made possible by a partnership with Planeteando and Geolatinas. Esta traducción fue posible gracias a una asociación con Planeteando y 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.

Rock Glacier Velocity: Monitoring Permafrost Amid Climate Change

EOS - Tue, 06/03/2025 - 12:00
Editors’ Vox is a blog from AGU’s Publications Department.

Rock glaciers are debris landforms found in many mountain ranges on Earth. They represent the movement of permanently frozen ground over long periods of time and can be used to understand how climate change is affecting permafrost.  

A new article in Reviews of Geophysics explores the use of “Rock Glacier Velocity” to measure how fast these landforms move each year, and its relationship with climatic factors. Here, we asked the authors to give an overview of Rock Glacier Velocity, how scientists measure it, and what questions remain.

What makes rock glaciers unique landforms? 

Rock glaciers primarily form where the ground temperature ranges from approximately -3 to 0°C. Generated by gravity-driven deformation of permafrost, rock glaciers exhibit distinct morphologies indicative of a cohesive flow. The motion mechanism, known as rock glacier creep, involves shearing in one or more layers (i.e., shear horizons) at depth within the permafrost and deformation of the frozen materials above. Changes in rock glacier creep rates depend primarily on changes in ground temperature. Rock glaciers provide a unique opportunity to indirectly document the evolution of permafrost temperatures in mountainous regions.

Remote sensing and field photos of rock glaciers. Credit: Hu et al. [2025], Figure 1

What is “Rock Glacier Velocity” and why is it important to measure? 

“Rock Glacier Velocity (RGV)” refers to the time series of annualized surface velocity reflecting the movement related to rock glacier creep. Since 2022, RGV has been accepted by the Global Climate Observing System (GCOS) as an Essential Climate Variable (ECV) Permafrost Quantity. An ECV is defined as “a physical, chemical, or biological variable (or group of linked variables) that is critical for characterizing the Earth’s climate.” An ECV Quantity is a measurable parameter necessary for characterizing an ECV. Rock Glacier Velocity is instrumental in assessing the state of permafrost under climate change, especially in places where direct monitoring is scarce. From a climate-oriented perspective, relative changes in Rock Glacier Velocity are significant.

What are the main factors that control Rock Glacier Velocity? 

Rock Glacier Velocity is collectively controlled by the geomorphologic features such as slope and landform geometry, as well as the thermo-mechanical properties of the frozen ground, such as ice content, subsurface structure, temperature, and the presence of unfrozen water under permafrost conditions. On a given rock glacier, relative changes in surface velocity over time usually reflect the climatic impacts, with temperature forcing being the dominant factor, especially when temperatures approach 0°C.

How do scientists observe and monitor Rock Glacier Velocity at different spatial scales? 

An illustration showing different survey methods for quantifying Rock Glacier Velocity. Credit: Hu et al. [2025], Figure 5a

Rock Glacier Velocity can be observed and monitored using in-situ and remote sensing methods. Global Navigation Satellite System (GNSS), theodolite, and total station surveys, provide point-based in-situ measurements. Regional-scale surveys typically employ remote sensing techniques, such as laser scanning, photogrammetry, radar interferometry, and radar offset tracking. In-situ RGV time series’ are rare and have mostly been provided from the European Alps, but they can be more than 20 years long. The goal is to leverage the experience gained from the systematic compilation of those in-situ time series to expand the RGV collection to regional-scale surveys using remote sensing techniques.

What kinds of patterns have been observed in Rock Glacier Velocity? 

According to the Rock Glacier Velocity data from across the European Alps, rock glaciers have generally accelerated alongside increasing air temperatures over the past three decades. At the interannual scale, RGV exhibits a regionally synchronous pattern with distinct acceleration phases (i.e., 2000–2004, 2008–2015, and 2018–2020) which are interrupted by deceleration or a steady kinematic state. However, systematic monitoring and documentation of Rock Glacier Velocity is currently lacking in many parts of the world.

How is climate change expected to influence Rock Glacier Velocity? 

Among the climatic factors, multi-annual air temperature changes primarily influence Rock Glacier Velocity by altering the ground thermal state of rock glaciers. Snow cover acts as an insulating layer whose development varies from year to year, causing the ground temperature to deviate from the air temperature on an interannual scale.

In general, warmer ground temperatures favor rock glacier movement. This pattern is expected to occur in many rock glaciers in the future as the climate continues to warm.  When the ground temperature reaches 0°C, some rock glaciers experience drastic acceleration. However, consequent thawing at the tipping point of 0°C causes the rock glacier creep to decline.

What are some of the remaining questions where additional modeling, data, or research efforts are needed? 

First, a standardized strategy for monitoring Rock Glacier Velocity using different methods is under development. We call for more systematic and consistent velocity measurements that can be used to generate Rock Glacier Velocity data products.

Second, the mechanisms linking climatic factors to Rock Glacier Velocity still need to be explored further, such as whether water infiltrates the partially frozen body of a rock glacier and how cold temperatures influence winter deceleration.

Additionally, an in-depth understanding of the relationship between Rock Glacier Velocity, environmental factors, and permafrost conditions requires observations combined with laboratory work and numerical modeling. This is necessary in order to incorporate rock glacier processes into land surface models and predict future changes in a warming climate.

—Yan Hu (huyan@link.cuhk.edu.hk, 0000-0001-8380-276X), University of Fribourg, Switzerland; and Reynald Delaloye (0000-0002-2037-2018), University of Fribourg, Switzerland

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: Hu, Y., and R. Delaloye (2025), Rock Glacier Velocity: monitoring permafrost amid climate change, Eos, 106, https://doi.org/10.1029/2025EO255017. Published on 3 June 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.

How a remote Antarctic base clean-up protected one of Earth's clearest lakes

Phys.org: Earth science - Tue, 06/03/2025 - 10:43
The clean-up and site restoration of a New Zealand research station in Antarctica has provided valuable lessons on the challenges of contaminated sites, according to a study in the journal Polar Record.

Distributively induced quasispherical implosion for fusion

Physical Review E (Plasma physics) - Tue, 06/03/2025 - 10:00

Author(s): Shu-Chao Duan, Shao-Tong Zhou, Gang-Hua Wang, Ming-Xian Kan, Qiang Xu, Bo Xiao, Hai-Bin Ou, Long Xie, and Qiang Wang

Inertial confinement of fusion plasmas can be realized using the dynamic Z pinch, an electromagnetically driven cylindrical implosion system that is also used to generate intense x rays. However, the Z pinch is subject to magnetic Rayleigh-Taylor (MRT) instability, which must be suppressed for pract…


[Phys. Rev. E 111, 065203] Published Tue Jun 03, 2025

Greenland's mega tsunamis: First direct observation of the trapped waves that shook the world

Phys.org: Earth science - Tue, 06/03/2025 - 09:00
In September 2023, a bizarre global seismic signal was observed which appeared every 90 seconds over nine days—and was then repeated a month later. Almost a year later, two scientific studies proposed that the cause of these seismic anomalies were two mega tsunamis which were triggered in a remote East Greenland fjord by two major landslides which occurred due to warming of an unnamed glacier.

Enhancing levee inspections with advanced technology

Phys.org: Earth science - Tue, 06/03/2025 - 08:31
In the United States, earthen levees are an integral part of flood control systems, protecting around 23 million Americans and crucial infrastructure. Recently, the American Society of Civil Engineers' 2025 Report Card for America's Infrastructure rated the nation's levees a D+, with an estimated $70 billion needed for maintenance to bring them into a state of good repair.

The 1 June 2025 landslides at Chaten in Sikkim, India

EOS - Tue, 06/03/2025 - 06:31

Nine people have been killed in a series of landslides, triggered by heavy rainfall, that have struck an army camp.

At about 7 pm local time on 1st June 2025, a series of landslides struck an army camp at Chaten in the Lachen District of Sikkim in India. It is believed that nine people have been killed, although at the time of writing six of these people were still missing, including an army officer, his wife and daughter.

Chaten is located at [27.7188, 85.5581]. This is a Google Earth image of the site, collected in March 2022:-

Google Earth image of the site of the 1 June 2025 landslide at Chaten in Sikkim, India.

The best imagery of the landslides that I have found is on a Youtube video posted by Excelsior News:-

This still captures the site well:-

The 1 June 2025 landslides at Chaten in Sikkim, India. Still from a video posted to Youtube by Excelsior News.

The image shows two main landslide complexes (plus one in the background). Each consists of a series of shallow slips on steep terrain – the one on the left has at least three initial failures, on the right there are also at least three). These have combined to create open hillslope landslides that have stripped the vegetation and surficial materials. Note the very steep lower slopes to the river.

These shallow landslide complexes are characteristic of extremely intense rainfall events, which saturate the soil and regolith from the boundary with the underlying bedrock. This causes a rapid loss of suction forces and a reduction in effective stress, triggering failure. The high water content of the soil then promotes mobility.

It is interesting to note that the natural vegetation has been removed from these slopes. It would be premature to assert that this was an underlying cause of the landslides, but it may have been a factor.

It appears that there has also been erosion of the riverside cliffs, which has left other parts of the camp in severe danger.

Sadly, given the terrain and the availability of people to participate in a rescue (which is one advantage of an event in an army camp), the prospects for those who are missing are not postive.

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.

Evaluation of a Generalized Least Squares Algorithm for Infrasound Beamforming with Coherent Background Noise

Geophysical Journal International - Tue, 06/03/2025 - 00:00
SummaryInfrasonic signals of interest can occur during periods with persistent, coherent, background noise, which may be natural or anthropogenic. For high signal-to-noise (SNR) ratio transient signals, an “overprinting” of the coherent background may occur, and the signal may still be detected. However, this approach fails for low SNR signals of interest, which may be obscured by coherent noise. An infrasound beamforming method based on generalized least squares (GLS) is investigated for detecting transient signals of interest in the presence of coherent and incoherent background noise. This approach relies on an estimate of the noise covariance, captured in a covariance matrix, to effectively null contributions to the array response from noisy directions of arrival. Synthetic array data is used to investigate the performance of the GLS beamformer compared to the Bartlett beamformer when coherent and incoherent backgrounds are present. Additionally, the effects of array element number and relative strength of the interfering signal on the GLS estimates is investigated. GLS empirical area under the curve estimates suggest that the beamformer can recover coherent power for a signal of interest lower in amplitude than the coherent background, but this effectiveness degrades more quickly with SNR for a four element array compared to a six or eight element infrasound array. Finally, infrasound from the Forensic Surface Experiment, a bolide signal observed at IMS array I37NO, and a volcanic signal recorded at the Alaska Volcano Observatory array ADKI are used to evaluate GLS performance on recorded data. A ten minute window was used to capture the background noise, and the coherent background signal was nulled in all three examples.

Subantarctic Mode Waters traced to distinct origins in Indian and Pacific oceans

Phys.org: Earth science - Mon, 06/02/2025 - 21:23
In the southern flanks of the Indian Ocean and the central and eastern Pacific, just north of the Antarctic Circumpolar Current, lie the Subantarctic Mode Waters. As part of the global ocean conveyor belt, these large masses of seawater transfer substantial amounts of heat and carbon northward into the interiors of the Indian and Pacific oceans. These waters hold about 20% of all anthropogenic carbon found in the ocean, and their warming accounted for about 36% of all ocean warming over the past two decades—making them critical players in Earth's climate system.

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