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Un repositorio de núcleos de coral diseñado para la transparencia y accesibilidad

EOS - Fri, 08/08/2025 - 12:02

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

Los arrecifes de coral son ecosistemas vitales que sustentan la vida marina, el ecoturismo y la protección costera. Ellos también guardan algo valioso bajo su superficie: registros del pasado del océano. Bajo la capa exterior viva de los corales masivos se encuentran estructuras esqueléticas tipo roca que contienen bandas anuales, similares a los anillos de árboles. Los científicos pueden estudiar las condiciones en el momento en que estas bandas se formaron mediante la perforación, recuperación y análisis de núcleos, algunos de los cuales representan siglos de crecimiento coral.

Daren Coker (izquierda) y Thomas DeCarlo perforan un núcleo de coral en el Mar Rojo. Crédito: Morgan Bennett-Smith

Desde la década de 1970, los estudios de núcleos de coral pueden determinar patrones de crecimiento pasados, un campo conocido como esclerocronología coralina, han producido descubrimientos científicos notables. Knutson et al. [1972] encontraron que las bandas anuales están compuestas por bandas de alta y baja densidad que reflejan patrones de crecimiento estacional. Hudson [1981] descubrió que, por lo general, las bandas de alta densidad se forman durante el crecimiento invernal más lento, mientras que las de baja densidad se forman durante el crecimiento del verano más rápido y que el crecimiento variable a largo plazo de corales están influenciadas por la calidad del agua y los efectos del desarrollo costero. Algunos núcleos también contienen “bandas de estrés” de alta densidad, formadas debido a eventos de blanqueamiento de corales u otros desafíos medioambientales [Lough, 2008]. En conjunto, estas bandas proporcionan información sobre la historia del crecimiento de coral, lo que permite a los científicos construir modelos de edad confiables de las condiciones oceánicas y climáticas pasadas.

Hoy en día, los métodos usados para investigar núcleos de corales han avanzado considerablemente. Junto con otros métodos, como los análisis de isótopos estables y de radio elementales, la tomografía computarizada (CT) desempeña un rol fundamental en la obtención de datos que ayudan a revelar los parámetros de crecimiento coralino. Los científicos pueden escanear rayos X en 2D y escaneo CT 3D para examinar las estructuras internas de núcleos coralinos, incluyendo sus bandas de densidad anual [Knutson et al., 1972; Hudson, 1981; Lough, 2008; DeCarlo et al., 2025]. En algunos casos, este análisis involucra incluso la visita de un científico a un hospital local para usar su equipo de CT – un paciente inesperado para el técnico de radiología.

Esta animación de una tomografía computarizada muestra un corte transversal de un núcleo de coral. Los pequeños círculos dentro del núcleo son coralitos, las estructuras esqueléticas individuales formadas por pólipos de coral. Crédito: USGS, Dominio público Un núcleo coralino se encuentra en la mesa de examen de un equipo de tomografía computarizada en un hospital antes de ser escaneado. Crédito: Thomas DeCarlo

Sin embargo, no se había realizado un archivo sistemático de datos de imágenes de núcleos coralinos, en parte debido a la falta de un repositorio adecuado. Esta brecha presenta el riesgo de perder imágenes valiosas e impide un intercambio ágil y transparente de las interpretaciones científicas de estas imágenes. Por lo tanto, un repositorio centralizado, virtual y de acceso abierto de imágenes de núcleos coralinos es crucial para fomentar la transparencia científica y preservar estos recursos para investigaciones futuras.

Una aplicación para organizar un repositorio

La aplicación CoralCT se desarrolló para consolidar y organizar escáneres de núcleos coralinos en un repositorio virtual que permite el archivo digital y el análisis de imágenes [DeCarlo et al., 2025]. Actualmente, el repositorio contiene más de 1,000 escaneos de corales recolectados en una amplia gama de regiones de arrecifes coralinos, que incluye la Gran Barrera de Coral, el Caribe y el Mar Rojo. Estos escaneos coralinos han sido aportados por individuos y agencias, como el Servicio Geológico de Estados Unidos (USGS, por sus siglas en inglés) y la Oficina Nacional de Administración Oceánica y Atmosférica (NOAA, por sus siglas en inglés).

Investigadores coralinos suben escaneos de rayos X o de CT a CoralCT y, cuando están listos, pueden hacer que sus datos estén públicamente disponibles para cualquier persona con una computadora y conexión a internet. Este enfoque de transparencia fomenta la colaboración entre investigadores de núcleos coralinos, quienes pueden consultar el directorio de núcleos de la aplicación y ver quién más ha recolectado núcleos en sus áreas de interés. Esto también ayuda a evitar la duplicación innecesaria de esfuerzos de investigación, lo cual es especialmente importante dada la necesidad de reducir el impacto del muestreo en los corales, muchos de los cuales son especies en peligro de extinción.

Utilizando las herramientas analíticas de la aplicación, los observadores pueden mapear las bandas de densidad anuales en núcleos coralinos para extraer datos sobre la tasa de crecimiento y la densidad esquelética. Tal como en estudios de anillos de árboles, este tipo de análisis ofrece información sobre las condiciones medioambientales pasadas, ya que el crecimiento de corales puede responder con sensibilidad a la variabilidad climática.

Por ejemplo, Barkley et al. [2018] utilizaron CoralCT para visualizar bandas de estrés de alta densidad y reconstruir la historia del blanqueamiento de corales a lo largo de seis décadas en un arrecife remoto del Océano Pacífico ecuatorial, donde el monitoreo de datos es escaso. Rodgers et al. [2021] midieron las tasas de crecimiento anual en CoralCT para rastrear la recuperación de corales frente a Kaua’i, Hawaii, en los 15 años posteriores a un evento de inundación devastadora. Más recientemente, DeCarlo et al. [2024] aprovecharon la amplitud de núcleos en CoralCT para reconstruir patrones de crecimiento coralinos en las décadas y siglos recientes a lo largo de miles de kilómetros en el Indo Pacífico.

Rescatando registros antiguos y recolectando nuevos

Archivar datos valiosos que de otro modo podrían perderse es el propósito fundamental de CoralCT. Un destacable ejemplo de cómo cumple este propósito involucra el rescate y la digitalización de imágenes de rayos X de más de 20 núcleos recolectados en el Océano Pacífico entre la década de los 1980 y principios de 2000. Las películas de rayos X, previamente guardadas por un científico jubilado, ahora están archivadas y disponibles para su análisis en CoralCT.

Colecciones más antiguas como estas pueden proporcionar información valiosa sobre el crecimiento coralino antes de que las perturbaciones medioambientales, como el blanqueamiento masivo por estrés térmico, comenzaran a afectarlos.

En un esfuerzo similar, la USGS escaneó recientemente núcleos coralinos en TC que datan de finales de la década de los 1960, algunos de los núcleos más antiguos jamás recolectados [Hudson et al., 1976]. Estos escaneos se están incorporando al repositorio para que puedan ser reanalizados por investigadores ahora y en el futuro. Colecciones más antiguas como estas pueden proporcionar información valiosa sobre el crecimiento coralino antes de que las perturbaciones medioambientales, como el blanqueamiento masivo por estrés térmico, comenzaran a afectarlos.

Además, a estas contribuciones históricas, el repositorio CoralCT continúa creciendo con la incorporación de nuevos datos. Una contribución reciente incluye escaneos de núcleos de arrecifes recolectados en la costa de Hawai’i en 2023 durante la Expedición 389 del Programa Internacional Ocean Discovery. Los núcleos de arrecifes difieren de los núcleos coralinos en composición y estructura, pero también son cruciales para entender la historia oceánica y el cambio medioambiental. Durante la expedición 389, se recolectaron núcleos de arrecifes sumergidos que una vez crecieron cerca de la superficie del océano, pero que dejaron de calcificarse a medida que se sumergían en aguas profundas. Estos núcleos de arrecifes contienen coral fragmentado, algas coralinas, microbialitos y otros materiales constructores de arrecifes, cuyas composiciones permiten a los científicos mirar milenos hacia el pasado y descubrir registros valiosos del nivel del mar y el cambio climático.

Análisis repetibles, resultados verificables

Cuando no se archivan imágenes de núcleos coralinos originales, sin procesar, el valor de las mediciones de crecimiento y otros análisis es limitado porque otros científicos no pueden verificarlos fácil e independientemente. Esto es problemático ya que la ciencia se basa fundamentalmente en la capacidad de repetir experimentos y verificar resultados, sobre todo considerando que investigadores individuales pueden introducir subjetividad y posibles sesgos incluso en interpretaciones de datos altamente sistemáticas y rigurosas. A medida que los conjuntos de datos se hacen más grandes, complejos y numerosos, mantener la transparencia es cada vez más importante, pero también cada vez más difícil.

En esta captura de pantalla de un núcleo coralino analizado en la aplicación CoralCT, las líneas naranjas en la imagen del núcleo indican dónde un observador ha mapeado las bandas de densidad anual. Crédito: Avi Strange

CoralCT aborda estos desafíos garantizando que toda la información y el contexto de un núcleo estén completamente documentados, accesibles y descargables. Esta información incluye metadatos esenciales tales como el origen del núcleo, los detalles de propiedad, la fecha de recolección, la profundidad y la identificación de especies. Y lo que es más importante, CoralCT archiva los mapas de bandas anuales definidos el usuario para derivar datos de la tasa de crecimiento [DeCarlo et al., 2025], asegurando que estos datos e interpretaciones sean totalmente reproducibles y estén abiertos a la verificaciones de otros.

Esta transparencia también se comparte entre los observadores dentro de la aplicación. Cuando un usuario mapea las bandas de un núcleo, este puede agregar notas y captura de pantalla que otros usuarios pueden ver mientras analizan dicho núcleo. Más aún, cuando un usuario termina de mapear las bandas de un núcleo y procesa los datos, esta información se almacena y se puede descargar para que otros científicos la consulten. Esta capacidad permite a los científicos realizar estudios con múltiples observadores, lo que puede reducir posibles sesgos introducidos por la observación individual.

Un desafío que hemos encontrado en nuestros esfuerzos para ampliar CoralCT ha sido la reticencia en algunos investigadores y programas a compartir datos.

A pesar de estas ventajas, un desafío que hemos encontrado en nuestros esfuerzos para ampliar CoralCT ha sido la reticencia en algunos investigadores y programas a compartir datos debido a la preocupación por las infracciones de propiedad intelectual y la “apropiación indebida” de datos prepublicados. Esta reticencia, que es entendible considerando la falta de transparencia y protección para los propietarios de los datos en las prácticas previas de gestión de datos, puede lamentablemente limitar los avances científicos y las colaboraciones que podrían ayudar a abordar el cambio climático, la degradación de arrecifes coralinos y otros desafíos complejos.

Para abordar estas preocupaciones, CoralCT ofrece controles privados a los propietarios de núcleos, que pueden usar para restringir el acceso a sus escaneos y a los datos derivados. Estos controles son particularmente útiles cuando los núcleos son parte de una investigación en curso que aún no se ha publicado o están sujetos a una moratoria posterior al crucero, lo que garantiza que datos sensibles permanezcan protegidos hasta que la investigación esté lista para ser compartida. Además, cada núcleo está identificado con el propietario de los datos, agradecimientos y citas relevantes.

Avanzando hacia la accesibilidad y colaboración

CoralCT también representa un camino para hacer la ciencia más inclusiva y accesible. La aplicación está diseñada con una interfaz fácil de usar e incluye recursos tales como videotutoriales y una guía de usuario paso a paso para ayudar a presentar sus funciones a un público amplio. Recientemente, también se crearon planes de clase para estudiantes de educación media y básica que guían a los estudiantes en el mapeo de las bandas de núcleos de coral en la aplicación, ofreciendo maneras accesibles de explorar las ciencias marinas.

Un estudiante de secundaria que visita el Laboratorio de Esclerocronología de la Universidad de Tulane usa un casco de realidad virtual para interactuar con núcleos coralinos en 3D durante el evento “Boys at Tulane in STEM 2025” de la universidad. Crédito: Danielle Scanlon Estudiantes de secundaria aprenden sobre núcleos de coral gracias a un holograma en un taller de la Universidad del Pacífico de Hawái. Crédito: Thomas DeCarlo

El potencial educacional de la aplicación se demostró en recientes eventos de divulgación. Utilizando tecnología de realidad virtual, estudiantes de secundaria en Nueva Orleans visualizaron escaneos 3D de núcleos de corales desde CoralCT y practicaron la identificación de bandas de densidad anual. En un evento similar, estudiantes de sexto grado en Hawái interactuaron con núcleos holográficos 3D coralinos y aprendieron cómo los científicos los extraen y estudian para comprender los patrones de crecimiento a lo largo del tiempo. Las experiencias positivas de estudiantes y profesores durante estos eventos demostraron cómo CoralCT brinda la oportunidad de interactuar de forma práctica con datos científicos reales.

La integración de IA también podría, y esto es importante, facilitar que todos los usuarios contribuyan al análisis de núcleos coralinos, independientemente de su formación académica o experiencia de campo.

De cara al futuro, existe la posibilidad de integrar inteligencia artificial (IA) en CoralCT para la identificación automatizada de patrones de bandas de coral. Si un sistema de IA se entrenara con interpretaciones humanas existentes, podría sugerir automáticamente marcas de bandas que los usuarios podrían revisar y verificar. Este avance ofrece la posibilidad de realizar análisis de núcleos coralinos más precisos y eficientes, manteniendo la supervisión humana. La integración de IA también podría, y esto es importante, facilitar que todos los usuarios contribuyan al análisis de núcleos coralinos, independientemente de su formación académica o experiencia de campo. Cada nueva contribución o análisis de un núcleo mejora la base de datos CoralCT y amplía nuestro conocimiento de los arrecifes de coral y las condiciones oceánicas pasadas.

La esclerocronología coralina es vital para comprender los cambios medioambientales en los ecosistemas de arrecifes coralinos y los impactos que estos cambios han provocado. Gracias a esta investigación, obtenemos información sobre el pasado del océano y mejoramos nuestra comprensión de los arrecifes de coral actuales. A medida que se intensifican las amenazas a los arrecifes, los grandes conjuntos de datos de acceso abierto son cada vez más esenciales para monitorear la salud de los arrecifes y predecir los impactos futuros.

Por lo tanto, CoralCT desempeña un papel importante en la preservación de valiosos registros del crecimiento de los corales y su historia medioambiental, a la vez que promueve el intercambio colaborativo, accesible y transparente de datos. Al poner la ciencia de los arrecifes de coral a disposición de investigadores y del público en general, conecta datos, ideas y personas para abordar cuestiones cruciales sobre nuestro mundo cambiante.

Agradecimientos

CoralCT se desarrolló con el apoyo de la subvención OCE-2444864 de la National Science Foundation. El uso de nombres comerciales, de empresas o de productos se realiza únicamente con fines descriptivos y no implica su respaldo por parte del gobierno de los Estados Unidos. Agradecemos al Equipo Científico de la Expedición IODP 389, al personal de apoyo del Operador Científico de ECORD (ESO), al equipo de perforación bentónica, a los topógrafos del MMA y al capitán y la tripulación del MMA Valour. La Expedición 389 del Programa Internacional de Ocean Discovery (IODP) contó con el apoyo financiero de las diversas agencias nacionales de financiación de los países participantes en el IODP. También agradecemos a todos los contribuyentes de datos hasta la fecha, entre ellos Giulia Braz, Jessica Carilli, Leticia Cavole, Ben Chomitz, Travis Courtney, Ian Enochs, Thomas Felis, Ke Lin, Malcolm McCulloch, Haojia Ren, Riccardo Rodolfo-Metalpa, Natan Pereira y al Programa de Recursos de Riesgos Costeros y Marinos del Servicio Geológico de los Estados Unidos.

Referencias

Barkley, H. C., et al. (2018), Repeat bleaching of a central Pacific coral reef over the past six decades (1960–2016), Commun. Biol., 1, 177, https://doi.org/10.1038/s42003-018-0183-7.

DeCarlo, T. M., et al. (2024), Calcification trends in long-lived corals across the Indo-Pacific during the industrial era, Commun. Earth Environ., 5, 756, https://doi.org/10.1038/s43247-024-01904-8.

DeCarlo, T. M., et al. (2025), CoralCT: A platform for transparent and collaborative analyses of growth parameters in coral skeletal cores, Limnol. Oceanogr. Methods, 23(2), 97–116, https://doi.org/10.1002/lom3.10661.

Hudson, J. H. (1981), Growth rates in Montastraea annularis: A record of environmental change in Key Largo Coral Reef Marine Sanctuary, Florida, Bull. Mar. Sci., 31(2), 444–459, www.ingentaconnect.com/content/umrsmas/bullmar/1981/00000031/00000002/art00014.

Hudson, J. H., et al. (1976), Sclerochronology: A tool for interpreting past environments, Geology, 4(6), 361–364, https://doi.org/10.1130/0091-7613(1976)4<361:SATFIP>2.0.CO;2.

Knutson, D. W., et al. (1972), Coral chronometers: Seasonal growth bands in reef corals, Science, 177(4045), 270–272, https://doi.org/10.1126/science.177.4045.270.

Lough, J. M. (2008), Coral calcification from skeletal records revisited, Mar. Ecol. Prog. Ser., 373, 257–264, https://doi.org/10.3354/meps07398.

Rodgers, K. S., et al. (2021), Rebounds, regresses, and recovery: A 15-year study of the coral reef community at Pila‘a, Kaua‘i after decades of natural and anthropogenic stress events, Mar. Pollut. Bull., 171, 112306, https://doi.org/10.1016/j.marpolbul.2021.112306.

Información de los autores

Avi Strange y Oliwia Jasnos, Universidad de Tulane, Nueva Orleans, Luisiana; Lauren T. Toth, Centro de Ciencias Costeras y Marinas de San Petersburgo, Servicio Geológico de Estados Unidos, Florida; Nancy G. Prouty, Centro de Ciencias Costeras y Marinas del Pacífico, Servicio Geológico de Estados Unidos, Santa Cruz, California; y Thomas M. DeCarlo (tdecarlo@tulane.edu), Universidad de Tulane, Nueva Orleans, Luisiana.

This translation by Daniela Navarro-Perez was made possible by a partnership with Planeteando and Geolatinas. Esta traducción fue posible gracias a una asociación con Planeteando y Geolatinas.

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Glacier Monitoring from Space Is Crucial, and at Risk

EOS - Fri, 08/08/2025 - 12:00

Shrinking glaciers present some of the most visible signs of ongoing anthropogenic climate change. Their melting also alters landscapes, increases local geohazards, and affects regional freshwater availability and global sea level rise.

Worldwide observations show that global glacier decline through the early 21st century has been historically unprecedented. Modeling research suggests that 16 kilograms of glacier ice melt for every kilogram of carbon dioxide (CO2) emitted, and other studies indicate that every centimeter of sea level rise exposes an additional 2–3 million people to annual flooding.

Science has benefited from a diverse set of spaceborne missions and strategies for estimating glacier mass changes at regional to global scales.

For more than 130 years, the World Glacier Monitoring Service and its predecessor organizations have coordinated international glacier monitoring. This effort started with the worldwide collection, analysis, and distribution of in situ observations [World Glacier Monitoring Service, 2023]. In the 20th century, remote sensing data from airborne and spaceborne sensors began complementing field observations.

Over the past 2 decades, science has benefited from a diverse set of spaceborne missions and strategies for estimating glacier mass changes at regional to global scales (see Figure 2 of Berthier et al. [2023]). However, this research is challenged by its dependence on the open accessibility of observations from scientific satellite missions. The continuation and accessibility of several satellite missions are now at risk, presenting potential major gaps in our ability to observe glaciers from space.

We discuss here the history, strengths, and limitations of several strategies for tracking changes in glaciers and how combining studies from the multiple approaches available—as exemplified by a recent large-scale effort within the research community—improves the accuracy of analyses of glacial mass changes. We also outline actions required to secure the future of long-term glacier monitoring.

The Glacier Mass Balance Intercomparison Exercise

Glaciological observations from in situ measurements of ablation and accumulation, generally carried out with ablation stakes and in snow pits, represent the backbone of glacier mass balance monitoring. For more than 30 years, glaciologists have undertaken this work at 60 reference glaciers worldwide, with some observations extending back to the early 20th century.

Researchers conduct glaciological fieldwork, using ablation stakes and other tools, on Findelengletscher in Zermatt, Switzerland, in October 2024. Credit: Andreas Linsbauer, University of Zurich

These observations provide good estimates of the interannual variability of glacier mass balance and have been vital for process understanding, model calibration, and long-term monitoring. However, because of the limited spatial coverage of in situ observations, the long-term trends they indicate may not accurately represent mass change across entire glacial regions, and some largely glacierized regions are critically undersampled.

Airborne geodetic surveys provide wider views of individual glaciers compared with point measurements on the ground, and comparing ice elevation changes in airborne data allows researchers to identify and quantify biases in field observations at the glacier scale [Zemp et al., 2013]. Meanwhile, geodetic surveys from spaceborne sensors enable many opportunities to assess glacier elevation and mass changes at regional to global scales.

The Glacier Mass Balance Intercomparison Exercise (GlaMBIE), launched in 2022, combined observations from in situ and remote sensing approaches, compiling 233 regional glacier mass change estimates from about 450 data contributors organized in 35 research teams.

The results of the Glacier Mass Balance Intercomparison Exercise show that since 2000, glaciers have lost between 2% and 39% of their mass depending on the region and about 5% globally.

The results of this community effort, published in February 2025, show that since 2000, glaciers have lost between 2% and 39% of their mass depending on the region and about 5% globally [The GlaMBIE Team, 2025]. These cumulative losses amount to 273 gigatons of water annually and contribute 0.75 millimeter to mean global sea level rise each year. Compared with recent estimates for the ice sheets [Otosaka et al., 2023], glacier mass loss is about 18% larger than the loss from the Greenland Ice Sheet and more than twice the loss from the Antarctic Ice Sheet.

GlaMBIE provided the first comprehensive assessment of glacier mass change measurements from heterogeneous in situ and spaceborne observations and a new observational baseline for global glacier change and impact assessments [Berthier et al., 2023]. It also revealed opportunities and challenges ahead for monitoring glaciers from space.

Strategies for Glacier Monitoring from Space

GlaMBIE used a variety of technologies and approaches for studying glaciers from space. Many rely on repeated mapping of surface elevations to create digital elevation models (DEMs) and determine glacier elevation changes. This method provides multiannual views of glacier volume changes but requires assumptions about the density of snow, firn, and ice to convert volume changes to mass changes, which adds uncertainty because conversion factors can vary substantially.

Optical stereophotogrammetry applied to spaceborne imagery allows assessment of glacier elevation changes across scales. Analysis of imagery from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on board Terra from 2000 to 2019 yielded elevation changes at 100-meter horizontal resolution for almost all of Earth’s glaciers [Hugonnet et al., 2021]. At the regional scale, finer spatial resolution is possible with the ongoing French Satellite pour l’Observation de la Terre (SPOT) mission series and with satellites like GeoEye, Pléiades, and WorldView.

The Glacier Mass Balance Intercomparison Exercise (GlaMBIE) used data from a fleet of satellites that monitor glaciers worldwide using optical, radar, laser, and gravity measurements. Clockwise from left in this image are illustrations of Terra, CryoSat, ICESat-2, and the twin GRACE spacecraft above a map of elevation change for the Vatnajökull ice cap in Iceland. Credit: ESA/NASA/Planetary Visions

Two spaceborne missions applying synthetic aperture radar (SAR) interferometry have been used to assess glacier elevation changes. In February 2000, the Shuttle Radar Topography Mission (SRTM) produced a near-global DEM at a spatial resolution of 30 meters. The second mission, TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X), has operated since 2010, providing worldwide DEMs at a pixel spacing of 12 meters.

Data from both missions can be used to assess glacier elevation changes in many regions [Braun et al., 2019], capitalizing on the high spatial resolution and the ability of radar signals to penetrate clouds. However, measurements using C- and X-band radar—as both SRTM and TanDEM-X have—are subject to uncertainties because of topographic complexity in high mountain terrain and because the radar signals can penetrate into snow and firn.

Laser and radar altimetry allow us to determine glacier elevation changes along ground tracks or swaths, which can be aggregated to produce regional estimates. Laser altimetry has been carried out by NASA’s Ice, Cloud and Land Elevation Satellites (ICESat and ICESat-2) and the Global Ecosystem Dynamics Investigation (GEDI) on board the International Space Station (ISS) [Menounos et al., 2024; Treichler et al., 2019].

Spaceborne gravimetry offers an alternative to elevation-focused methods, allowing scientists to estimate mass changes by measuring changes in Earth’s gravitational field.

Spaceborne radar altimetry has a long tradition of measuring ocean and land surfaces, but these missions’ large detection footprints and the challenges of mountainous terrain hampered the use of early missions (e.g., ERS, Envisat) for glacier applications. The European Space Agency’s (ESA) CryoSat-2, which launched in 2010, offered improved coverage of the polar regions, denser ground coverage, a sharper footprint, and other enhanced capabilities that opened its use for monitoring global glacier elevation changes [Jakob and Gourmelen, 2023].

Both laser altimetry and radar altimetry provide elevation change time series at monthly or quarterly resolution for regions with large ice caps and ice fields (e.g., Alaska, the Canadian Arctic, Svalbard, and the periphery of the Greenland and Antarctic Ice Sheets). However, assessing mountain regions with smaller glaciers (e.g., Scandinavia, central Europe, Caucasus, and New Zealand) remains challenging because of the complex terrain and limited spatial coverage.

Spaceborne gravimetry offers an alternative to elevation-focused methods, allowing scientists to estimate mass changes across the ocean and in water and ice reservoirs by measuring changes in Earth’s gravitational field. Two missions, the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE) and the NASA/GFZ Helmholtz Centre for Geosciences GRACE Follow-on mission (GRACE-FO), have provided such measurements almost continuously since 2002.

Gravimetry offers more direct estimates of glacier mass change than other methods [Wouters et al., 2019]. However, the data must be corrected to account for effects of atmospheric drag and oceanic variability, glacial isostatic adjustment, nonglacier hydrological features, and other factors [Berthier et al., 2023].

Estimates from the GRACE and GRACE-FO missions are most relevant for regions with large areas of glacier coverage (>15,000 square kilometers) because of the relatively coarse resolution (a few hundred kilometers) of the gravity data and because of issues such as poor signal-to-noise ratios in regions with small glacier areas and related small mass changes.

Securing Glacier Monitoring over the Long Term

The work of GlaMBIE to combine observations from the diverse approaches above points to several interconnected requirements and challenges for improving the comprehensiveness of global glacier change assessments and securing the future of long-term glacier monitoring.

First, we must extend the existing network of in situ glaciological observations to fill major data gaps. Such gaps remain in many regions, including Central Asia, Karakoram, Kunlun, and the Central Andes, where glaciers are vital for freshwater availability, as well as in the polar regions, where glaciers are key contributors to sea level rise. These networks also need to be updated to provide real-time monitoring, which will improve understanding of glacier processes and help calibrate and validate remote sensing data and numerical modeling.

A sequence of aerial photographs taken in 1980 from about 11,000-meter altitude of Grey Glacier in the Southern Patagonian Ice Field (top) was used to generate a 3D model of the glacier (bottom). Credit: 3D reconstruction by Livia Piermattei and Camilo Rada using images from the Servicio Aerofotogramétrico de la Fuerza Aérea de Chile (SAF)

Second, we must continue unlocking historical archives of airborne and spaceborne missions to expand the spatiotemporal coverage of the observations used in glacier mass change assessments. Data from declassified spy satellites, such as CORONA and Hexagon, have provided stereo observing capabilities at horizontal resolutions of a few meters and offer potential to assess glacier elevation changes back to the 1960s and 1970s. Aerial photography has provided unique opportunities to reconstruct glacier changes since the early 20th century, such as in Svalbard, Greenland, and Antarctica. Beyond individual and institutional studies, we need open access to entire national archives of historical images to safeguard records of past glacier changes on a global scale.

We must ensure the continuation of space-based glacier monitoring with open-access and high-resolution sensors.

Third, we must ensure the continuation of space-based glacier monitoring with open-access and high-resolution sensors, following the examples of the Sentinel missions, SPOT 5, and Pléiades. For optical sensors, there is an urgent need for new missions collecting open-access, high-resolution stereo imagery. The French space agency’s forthcoming CO3D (Constellation Optique en 3D) mission, scheduled for launch in 2025, will help meet this need if its data are openly available. But with the anticipated decommissioning of ASTER [Berthier et al., 2024] and the suspended production of new ArcticDEM and REMA (Reference Elevation Model of Antarctica) products from WorldView satellite data as a result of recent U.S. funding cuts, additional replacement missions are needed to observe elevation changes over individual glaciers.

For radar imaging and altimetry, the SAR mission TanDEM-X and the radar altimeter CryoSat-2 are still operating with expected mission extensions into the late 2020s, and ESA’s SAR-equipped Harmony mission is expected to launch in 2029. With the planned launch of the Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL) in 2027, ESA aims to establish a long-term, cryosphere-specific monitoring program.

The challenge with CRISTAL will be to ensure that its sensor and mission specifications are tailored for application over glaciers—a difficult task because of glaciers’ relatively small sizes, steep slopes, and distribution in mountain terrain. In the event of a gap between the end of CryoSat-2 and the start of CRISTAL, a bridging airborne campaign, similar to NASA’s Operation IceBridge between ICESat and ICESat-2, will be needed.

Grosser Aletschgletscher in Switzerland, seen in October 2015. Credit: Jürg Alean, SwissEduc, Glaciers online

For laser altimetry, we may face gaps in observations as well, as no follow-on is planned for the current ICESat-2 and GEDI science missions. ICESat-2, which measures Earth’s glacier topography and provides validation and coregistration points for other altimetry missions, is projected to run until the early to mid-2030s, but continuing missions must be initiated now. Future missions should combine high accuracy with full coverage over individual glaciers. Proposed concepts with swath lidar, such as EDGE (Earth Dynamics Geodetic Explorer) and CASALS (Concurrent Artificially-Intelligent Spectrometry and Adaptive Lidar System), could be game changers for repeated mapping because they would provide full coverage of glacier topography. Advancing Surface Topography and Vegetation (STV) as a targeted observable for NASA missions, as recommended by the National Academies’ 2017–2027 Decadal Survey, could extend such observations beyond the current science missions.

For gravimetry, we also face a potential gap in observations, depending on when GRACE-FO is decommissioned and when approved follow-up missions—GRACE-C and NGGM (Next Generation Gravity Mission)—launch. Regardless of launch dates, the usefulness of future missions for monitoring glacier mass changes across regions will strongly depend on the spatial resolution of their data and on the ability to separate glacier and nonglacier signals. Cofounded gravity missions such as the Mass-Change and Geosciences International Constellation (MAGIC), a planned joint NASA-ESA project with four satellites operating in pairs, could significantly improve the spatial and temporal resolution of the gravity data and their utility for glacier monitoring.

Bringing It All Together

Glaciers worldwide are diminishing at alarming rates, affecting everything from geohazards to freshwater supplies to sea level rise.

Glaciers worldwide are diminishing with global warming, and they’re doing so at alarming rates, affecting everything from geohazards to freshwater supplies to sea level rise. Understanding as well as possible the details of glacier change from place to place and how these changes may affect different communities requires combining careful observations from a variety of field, airborne, and—increasingly—spaceborne approaches.

In light of major existing and impending observational gaps, the scientific community along with government bodies and others should work together to expand access to relevant historical data and extend present-day monitoring capabilities. Most important, space agencies and their sponsor nations must work rapidly to replace and improve upon current satellite missions to ensure long-term glacier monitoring from space. Given the climate crisis, we also call for open scientific access to data from commercial and defense missions to fill gaps and complement civil missions.

As the work of GlaMBIE reiterated, the more complete the datasets we have, the better positioned we will be to comprehend and quantify glacier changes and related downstream impacts.

Acknowledgments

We thank Etienne Berthier, Dana Floricioiu, and Noel Gourmelen for their contributions to this article and all coauthors and data contributors of GlaMBIE for constructive and fruitful discussions during the project, which built the foundation to condense the information presented here. This article was enabled by support from ESA projects GlaMBIE (4000138018/22/I-DT) and The Circle (4000145640/24/NL/SC), with additional contributions from the International Association of Cryospheric Sciences (IACS).

References

Berthier, E., et al. (2023), Measuring glacier mass changes from space—A review, Rep. Prog. Phys., 86(3), 036801, https://doi.org/10.1088/1361-6633/acaf8e.

Berthier, E., et al. (2024), Earth-surface monitoring is at risk—More imaging tools are urgently needed, Nature, 630(8017), 563, https://doi.org/10.1038/d41586-024-02052-x.

Braun, M. H., et al. (2019), Constraining glacier elevation and mass changes in South America, Nat. Clim. Change, 9(2), 130–136, https://doi.org/10.1038/s41558-018-0375-7.

Hugonnet, R., et al. (2021), Accelerated global glacier mass loss in the early twenty-first century, Nature, 592(7856), 726–731, https://doi.org/10.1038/s41586-021-03436-z.

Jakob, L., and N. Gourmelen (2023), Glacier mass loss between 2010 and 2020 dominated by atmospheric forcing, Geophys. Res. Lett., 50(8), e2023GL102954, https://doi.org/10.1029/2023GL102954.

Menounos, B., et al. (2024), Brief communication: Recent estimates of glacier mass loss for western North America from laser altimetry, Cryosphere, 18(2), 889–894, https://doi.org/10.5194/tc-18-889-2024.

Otosaka, I. N., et al. (2023), Mass balance of the Greenland and Antarctic Ice Sheets from 1992 to 2020, Earth Syst. Sci. Data, 15(4), 1,597–1,616, https://doi.org/10.5194/essd-15-1597-2023.

The GlaMBIE Team (2025), Community estimate of global glacier mass changes from 2000 to 2023, Nature, 639, 382–388, https://doi.org/10.1038/s41586-024-08545-z.

Treichler, D., et al. (2019), Recent glacier and lake changes in high mountain Asia and their relation to precipitation changes, Cryosphere, 13(11), 2,977–3,005, https://doi.org/10.5194/tc-13-2977-2019.

World Glacier Monitoring Service (2023), Global Glacier Change Bulletin No. 5 (2020–2021), edited by M. Zemp et al., 134 pp., Zurich, Switzerland, https://wgms.ch/downloads/WGMS_GGCB_05.pdf.

Wouters, B., A. S. Gardner, and G. Moholdt (2019), Global glacier mass loss during the GRACE satellite mission (2002–2016), Front. Earth Sci., 7, 96, https://doi.org/10.3389/feart.2019.00096.

Zemp, M., et al. (2013), Reanalysing glacier mass balance measurement series, Cryosphere, 7(4), 1,227–1,245, https://doi.org/10.5194/tc-7-1227-2013.

Author Information

Michael Zemp (michael.zemp@geo.uzh.ch), University of Zurich, Switzerland; Livia Jakob, Earthwave Ltd., Edinburgh, U.K.; Fanny Brun, Université Grenoble Alpes, Grenoble, France; Tyler Sutterley, University of Washington, Seattle; and Brian Menounos, University of Northern British Columbia, Prince George, Canada

Citation: Zemp, M., L. Jakob, F. Brun, T. Sutterley, and B. Menounos (2025), Glacier monitoring from space is crucial, and at risk, Eos, 106, https://doi.org/10.1029/2025EO250290. Published on [DAY MONTH] 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.

The challenges of the valley blocking landslide in the Matia’an Valley in Wanrong township, Taiwan

EOS - Fri, 08/08/2025 - 06:30

The 21 July 2025 rock avalanche is generating a lake that could have a volume of 86 million cubic metres at the point of overtopping. This poses a threat to at least seven downstream communities in east Taiwan.

Yesterday, I posted about the enormous 21 July 2025 rock avalanche in the Matia’an valley, in Wanrong township in eastern Taiwan. Coincidentally, etaiwan.news has posted an article about the landslide that includes some images of it, and that highlights the growing concerns about the potential hazard from the landslide dammed lake.

So, let’s start with the images. This is the headscarp area:

The headscarp area of the 21 July 2025 landslide in the Matia’an valley in Taiwan. Image by etaiwan.news.

The large source area is clear in the upper left of the image. Note the dust cloud from continued rockfall activity. The initial track of the landslide has left a complex topography that includes bare rock and some landslide material (especially on the right side of the image).

This image captures the lake that is forming:-

The barrier lake of the 21 July 2025 landslide in the Matia’an valley in Taiwan. Image by etaiwan.news.

Note the very substantial height difference between the lake and the top of the landslide deposit. Given that this valley was free draining before the landslide occurred, this must all be landslide material. As such it is erodable in the event of overtopping.

Finally, this is a view of the whole length of the landslide:-

The entire track of the 21 July 2025 landslide in the Matia’an valley in Taiwan. Image by etaiwan.news.

Again, note the height of the saddle formed from landslide material. The deposit appears on first inspection to be steep, which suggests it might be quite erodible.

The etaiwan.news article highlights work being undertaken by the Hualien Branch of the Forestry Conservation Department to understand the hazard. The statistics of the dam are concerning:

As of 7 August 2025At overtoppingLake volume23 million m386 million m3Lake length1,770 m2,900 m

The current freeboard is 79 m. Current inflow into the lake is 920,000 m3 per day, giving an overtopping date of mid-October at current rates (but see below).

A key issue is then the assets at risk downstream. This is a Google Earth image of the channel entering the Longitudinal Valley:-

Google Earth image of downstream assets from the landslide dam in the Matia’an Valley in Taiwan.

The article mentions that the risk will extend to:-

“will include the Matai’an Creek Bridge on the downstream Taiwan Line 9 [this is main highway on the eastern side of Taiwan], public and private river defence facilities and settlements on both sides of the river, and the administrative area covers Mingli Village, Dama Village, Daping Village, Dongfu Village in Wanrong Township, and Changqiaoli, Darongli and Shanxingli in Fenglin Township.”

Taiwan is well-placed to manage this hazard, but it is going to be a major issue in the coming weeks. Finally, as noted above, the overtopping date is estimated from current inflow rates. But, the next few weeks are the peak of the typhoon season, which can bring exceptional rainfall.

And, right on cue, Tropical Storm Podul has formed to the east of Taiwan, and is now moving westward. It is too early to tell whether this will bring heavy rainfall to the Matia’an valley (it is likely to pass by Taiwan on about 13 – 14 August), but if it does then this will accelerate the filling of the lake. Even if it does not bring heavy rainfall, the development of another typhoon that affects this area in the next two months would not be a surprise.

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New study reveals surprising clues about the beginning of subduction on Earth

Phys.org: Earth science - Thu, 08/07/2025 - 19:50
Subduction, a crucial geological process on Earth, may have begun hundreds of millions of years earlier than traditionally believed.

Machine learning predicts global glacier erosion rates with new precision

Phys.org: Earth science - Thu, 08/07/2025 - 19:31
Glaciers carved the deep valleys of Banff, eroded Ontario to deposit the fertile soils of the Prairies, and continue to change Earth's surface. But how fast do glaciers sculpt the landscape?

US-French SWOT satellite measures tsunami after massive quake

Phys.org: Earth science - Thu, 08/07/2025 - 19:31
The SWOT (Surface Water and Ocean Topography) satellite captured the tsunami spawned by an 8.8 magnitude earthquake off the coast of Russia's Kamchatka Peninsula on July 30, 11:25 a.m. local time. The satellite, a joint effort between NASA and the French space agency CNES (Centre National d'Études Spatiales), recorded the tsunami about 70 minutes after the earthquake struck.

Rogue waves demystified: Giant seas are just the ocean's 'bad day'

Phys.org: Earth science - Thu, 08/07/2025 - 16:39
On New Year's Day 1995, a monstrous 80-foot wave in the North Sea slammed into the Draupner oil platform. The wall of water crumpled steel railings and flung heavy equipment across the deck—but its biggest impact was what it left behind: hard data. It was the first time a rogue wave had ever been measured in the open ocean.

As the Colorado River slowly dries up, states angle for influence over future water rights

Phys.org: Earth science - Thu, 08/07/2025 - 15:59
The Colorado River is in trouble: Not as much water flows into the river as people are entitled to take out of it. A new idea might change that, but complicated political and practical negotiations stand in the way.

An integrated vision of Earth's natural 'CO&#8322; vacuum cleaners'

Phys.org: Earth science - Thu, 08/07/2025 - 15:00
Natural weathering processes are removing CO2 from the air in a wide range of environments across continents and oceans. Until recently, these "CO2 vacuum cleaners" were often studied separately, without properly examining their complex interactions.

Perito Moreno Glacier's retreat accelerates, raising concerns about future stability

Phys.org: Earth science - Thu, 08/07/2025 - 15:00
The Perito Moreno Glacier in Argentina—often described as one of the most stable glaciers in Patagonia—is retreating far more rapidly than previously thought, according to a paper in Communications Earth & Environment. The results show that over the last few years, the glacier has retreated by as much as 800 meters in some areas, and that it may collapse and retreat by several kilometers in the near future.

Unprecedented heat in North China: How soil moisture amplified 2023's record heat wave

Phys.org: Earth science - Thu, 08/07/2025 - 14:29
This summer, much of North China has endured widespread temperatures above 35°C. Even typically cooler, high-latitude summer retreats like Harbin in Northeast China—usually a refuge from the heat—saw temperatures soar past 35°C in late June and July. As climate change accelerates, extreme heat events will become increasingly frequent.

Can Microorganisms Thrive in Earth’s Atmosphere, or Do They Simply Survive There?

EOS - Thu, 08/07/2025 - 13:07
Source: Journal of Geophysical Research: Biogeosciences

Earth’s atmosphere transports tiny forms of cellular life, such as fungal spores, pollen, bacteria, and viruses. On their journeys, these microorganisms encounter challenging conditions such as cold temperatures, UV radiation, and a lack of nutrient availability. Previous research showed that certain microorganisms can withstand these harsh conditions and potentially reside in dormancy until being deposited in a more favorable environment. But could the atmosphere itself also be the site of an active microbial system, harboring growing, adapted, and resident microorganisms?

The study of these floating life-forms is called aerobiology, but progress in the field is difficult to make: No standardized method exists for sampling the aeromicrobiome, it’s common for microbe samples to become contaminated, and it’s challenging to replicate atmospheric conditions in a laboratory setting.

Martinez-Rabert et al. suggest that computer modeling and theoretical approaches could help to improve understanding of the aeromicrobiome. Using known information about the metabolism and bioenergetics of microbial life—especially in harsh environments—as well as the chemistry and physics of the atmosphere, specialized modeling frameworks may be able to provide insight into the aeromicrobiome.

That bottom-up modeling approach, the researchers propose, could allow them to test how changing individual elements of Earth’s atmosphere would affect the proliferation of the microbial life it contains. For instance, are microbes better suited to a “free-living” lifestyle in atmospheric gases, inside droplets, or attached to solid particles? What energy sources are available to these microorganisms? How does the acidity of atmospheric aerosols affect the ability of atmospheric microorganisms to thrive?

The group suggests that combined with data generated through sampling measurements, experiments, and observations, theoretical modeling could help researchers to assess our atmosphere’s capacity to sustain a microbial biosphere and even to learn more about how microorganisms influence the atmosphere’s chemical makeup. This work could also someday be useful for modeling how life may exist in other planetary atmospheres, the researchers say. (Journal of Geophysical Research: Biogeosciences, https://doi.org/10.1029/2025JG009071, 2025)

—Rebecca Owen (@beccapox.bsky.social), Science Writer

Citation: Owen, R. (2025), Can microorganisms thrive in Earth’s atmosphere, or do they simply survive there?, Eos, 106, https://doi.org/10.1029/2025EO250293. Published on 7 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.

Coral Cores Pinpoint Onset of Industrial Deforestation

EOS - Thu, 08/07/2025 - 13:06

In Malaysian Borneo, demand for timber, land, and palm oil has caused profound levels of deforestation. But the lack of historic data on the region’s rainforests has left scientists without much understanding of these forests’ baseline—what did they look like before industrial logging began?

Researchers have now found records hidden in an unexpected place. A new study, published in Scientific Reports, used corals from three reefs off the coast of Malaysian Borneo to build a timeline of deforestation and erosion on the island. The timeline provides valuable information for researchers and policymakers about how coral reefs are affected by deforestation as well as what Malaysian forests looked like in Earth’s past.

The study “allows us to have an idea of what the system looked like when it was relatively undisturbed,” said Walid Naciri, a geologist and lead author of the new study; he completed the research during his doctoral studies at the University of Leicester in the United Kingdom.

Coral Clues

Scientists can track deforestation trends with satellite imagery, but no such records exist before the onset of the satellite era around 1973.

Corals can be used as a proxy: They build themselves in alternating dark and light bands that, like trees, correspond to seasonal changes. As they grow, they absorb elements from seawater.

Corals’ ratio of barium, an element mostly found on land, to calcium, a common element in the ocean, can indicate the sediment content in river discharge that has reached a reef. Increased river discharge is an indicator of excess erosion, a consequence of deforestation. By analyzing the ratio of barium to calcium in a given band, scientists can determine the seawater composition in a given year.

“It’s a very well known impact of deforestation that you have less soil stability and more soil erosion ultimately arriving into the coastal ecosystem.”

Previous work by Naciri indicated that the barium-calcium ratio in corals matched river discharge data from the Baram River in Malaysian Borneo from 1985 to 2015. “We thought, okay, this is a pretty good analogue…so let’s have a look at the entirety of the record,” Naciri said.

The research team wanted to see whether they could use that ratio to construct a record of deforestation before 1985. They selected three separate reefs in the Miri-Sibuti Coral Reef National Park off the coast of Borneo. The three reefs, named Eve’s Garden, Anemone Garden, and Siwa, were located at different distances from the main sources of sediment: the Baram and Miri Rivers.

The team took cores of each reef and analyzed the ratios of barium to calcium. The resulting records were almost exactly what Naciri expected—cores from each of the three reefs showed a relatively flat trend until barium spiked beginning in the mid-20th century. The spike showed up later in the reefs farther from the island.

“We were pretty sure this was due to deforestation, because it’s a very well known impact of deforestation that you have less soil stability and more soil erosion ultimately arriving into the coastal ecosystem,” Naciri said. “But we needed a bit more proof.”

The team found archival forestry records that matched the mid-20th-century spike, indicating that the onset of industrial deforestation occurred around 1955. A previous analysis of land use across all of Southeast Asia from 1700 to 1990 showed a similar trend.

Naciri and his colleagues also ruled out other potential causes of the barium spike. They analyzed seawater at various distances from the Baram River to show that the barium was coming from the river rather than from leaching groundwater, for example.

The study’s authors did careful analytical work to rule out other interpretations of the data, said Dominik Fleitmann, a paleoclimatologist at the University of Basel in Switzerland who was not involved in the new study. Having three sites at varying distances from the island “adds confidence to the general reconstruction,” he said. 

The Far-Reaching Effects of Deforestation

The findings highlight how the impacts of on-land ecosystem degradation trickle down to coral ecosystems. Coral reefs rely on photosynthesis. Any influx of sediment into a reef clouds the water and harms coral’s ability to grow and even affects its ability to fight off diseases. 

“This is one more impact of deforestation that is really not talked about.”

“This is one more impact of deforestation that is really not talked about,” Naciri said. 

He urged other scientists studying deforestation to think outside of their usual study spaces and consider how marine ecosystems might be affected. “It’s an even worse problem than we think it is,” he said. 

Fleitmann said the results clearly show that “we are well above the natural variability in terms of soil erosion increases” and that the data could be useful to show policymakers the impacts of deforestation. 

The study could also be the beginning of a larger network of coral cores that could be used to build a more systematic reconstruction of deforestation records across larger areas of interest, such as the Australian or East African coast, he said. “What is the natural baseline, and how far away are we?”

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

Citation: van Deelen, G. (2025), Coral cores pinpoint onset of industrial deforestation, Eos, 106, https://doi.org/10.1029/2025EO250289. Published on 7 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.

Laser analysis enables industry to map mineral samples at an unprecedented scale

Phys.org: Earth science - Thu, 08/07/2025 - 12:59
Critical mineral lithium—the lightest of all metals—had long eluded geologists by slipping through the cracks of traditional analysis.

How Flexible Enhanced Geothermal Systems Control Their Own Seismicity

EOS - Thu, 08/07/2025 - 12:00
Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Journal of Geophysical Research: Solid Earth

Previous studies of the microearthquakes (MEQs) produced from Enhanced Geothermal Systems (EGSs) have focused on the initial phase of high‑pressure “stimulation.” Chamarczuk et al. [2025] track what happens during normal operation, the phase in which plants will spend most of their lives.

Using a distributed acoustic sensing (DAS) cable in a monitoring well and on‑site processing, the authors built a two‑month MEQ catalog through stimulation, crossflow testing, and five load‑following cycles. During those cycles, seismicity rose and fell with subsurface fluid pressure, then settled toward an equilibrium between injections. Event locations formed a cloud whose growth matched a simple diffusion model, which points to pressure migration as the main earthquake triggering mechanism.

These observations suggest that operators have the ability to control seismicity through careful management of injection rates and fluid pressure. They also demonstrate that affordable, real‑time monitoring is feasible for future commercial projects.

Citation: Chamarczuk, M., Ajo-Franklin, J., Nayak, A., Norbeck, J., Latimer, T., Titov, A., & Dadi, S. (2025). Insights into seismicity associated with flexibly operating enhanced geothermal system from real-time distributed acoustic sensing. Journal of Geophysical Research: Solid Earth, 130, e2025JB031634. https://doi.org/10.1029/2025JB031634

—David Dempsey, Associate Editor, JGR: Solid Earth

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.

Kinetic full-wave analysis of injected electromagnetic wave in an inhomogeneous hot plasma

Physical Review E (Plasma physics) - Thu, 08/07/2025 - 10:00

Author(s): Shabbir A. Khan and Atsushi Fukuyama

Linear absorption of electromagnetic wave injected in a hot plasma is usually associated with non-normal incidence; here, it is shown that absorption can take place at normal incidence as well. By developing a kinetic model based on integral form of dielectric tensor in the presence of static electr…


[Phys. Rev. E 112, L023202] Published Thu Aug 07, 2025

Microearthquakes in New Zealand's Southern Alps more common after seasonal snowmelt, heavy rainfall

Phys.org: Earth science - Thu, 08/07/2025 - 08:49
Changes in water levels beneath Earth's surface caused by glacier snowmelt and rainfall could be responsible for triggering small but frequent earthquakes in New Zealand's central Southern Alps, according to new research led by The Australian National University (ANU), published in the journal Geochemistry, Geophysics, Geosystems.

The 21 July 2025 giant rock avalanche in Wanrong township, Taiwan

EOS - Thu, 08/07/2025 - 06:55

On 21 July 2025, a very large rock avalanche occurred in the mountains of Hualien County, Taiwan. Initial measurements suggest that this ran out over about 6 km.

On 21 July 2025, an extremely large rock avalanche occurred in the administrative area of Wanrong Township in Hualien Count in Taiwan. This event was detected on seismic data and it has been described on Facebook by Chen-Yu Chen. In the days before the landslide, southern Taiwan had been affected by heavy rainfall associated with the passage of Tropical Storm Wipha.

The crown of the landslide is at [23.72645, 121.29021]. A rough measurement suggests that it is in the order of 6 km long and 2 km wide. The location is steep and rugged – this is a Google Earth image of the site of the landslide:-

Google Earth image of the site of the 21 July 2025 landslide in Wanrong township, Taiwan.

As the image above shows, the area affected by the rock avalanche is exceptionally steep (even by Taiwan standards) and deeply dissected, suggesting regular landslide activity. I will return to this theme in a future post.

This is a Planet Labs image of the site, draped onto the Google Earth DEM, captured on 25 July 2025. So far, this is the only image of the site that I have been able to access – this part of Taiwan is exceptionally cloudy at this time of the year. Whilst some of the landslide is covered in cloud, most is visible.

Planet Labs image, draped onto the Google Earth DEM, showing the site of the 21 July 2025 landslide in Wanrong township, Taiwan. Satellite image copyright Planet Labs, used with permission. Image dated 25 July 2025.

Of particular note is the large-scale of the event, the long runout and the large amount of dust on the adjacent slopes. Note also the lake that has started to develop – it is reported on Facebook that the hazard associated with this is being managed.

The crown of the landslide is at about 2,450 metres and the toe is at roughly 700 metres, so this has a vertical extent of about 1,750 metres.

Here is an initial slider of the before and after images of the landslide:-

This is probably the largest landslide in Taiwan by volume since the Tsaoling rock avalanche and the Chiufengershan rock avalanche, both triggered by the Ch-Chi earthquake in 1999. However, the runout of the Wanrong landslide is, I think, larger than both of these landslides. I do not have a volume estimate at this point.

In the autumn, it is likely that clear imagery will become available of this exceptional landslide. However, Taiwan is likely to be affected by further heavy rainfall in the coming weeks, so the landslide might evolve further.

Reference and acknowledgement

Many thanks to Brian Yanites of Indiana University Bloomington for highlighting this event, and for his work on the landslide.

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

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Study of the lithospheric structure beneath Northeast Brazil with P-wave multiple frequency seismic tomography

Geophysical Journal International - Thu, 08/07/2025 - 00:00
SummaryWe used the multiple-frequency seismic tomography method to image the upper mantle beneath Northeast Brazil by processing P-wave broadband seismograms in six frequency passbands. The data comprised 87 896 relative traveltime residuals for P and PKIKP phases, simultaneously inverted to obtain 3D models of P-velocity anomalies. We conducted resolution tests using checkerboard patterns with horizontal dimensions of 312×312 km and 390×390 km. For the 312×312 km structures, we observed good horizontal recovery beneath the areas of the Borborema province and northern São Francisco craton at the depths of 136 and 226 km, with the areas of the São Luís craton and Parnaíba basin also presenting recovery, albeit with reduced amplitudes. For the 390×390 km structures we observed good horizontal and amplitude recovery throughout the entire study area. Our model was unable to recover the sharp vertical transitions between the anomalies. We present the preferred model for Parnaíba basin and Borborema province. The model shows a fragmented basement for the Parnaíba basin, with two strong high-velocity anomalies consistent with the Parnaíba and Granja blocks, and another slight high-velocity anomaly north of the basin, consistent with the São Luís craton. To the west of the basin, the Parnaíba block appears separate from another high-velocity anomaly associated with the Amazonian craton. A strong high-velocity anomaly south of the Borborema province is interpreted as the northern portion of the São Francisco craton. The São Francisco craton anomaly presents strong high-velocity anomalies, interpreted as a thickening of certain portions of the craton, separated by a weaker positive anomaly, interpreted as the Paramirim Aulacogen. The Borborema province is characterized by a low-velocity anomaly. The central and northeastern portions of this anomaly presented even lower velocities, which was interpreted as lateral flow in the asthenosphere, originating from the passage of a plume to the north of the province. A low-velocity anomaly located west of the Borborema province strikes roughly NE-SW and separates the São Francisco craton from the Parnaíba block and the Amazonian craton. It is interpreted as the Transbrasiliano Lineament. To test the capability of our data to resolve the limits of large-scale structures, we created four synthetic models simulating the presence of different cratonic nuclei. The models show good horizontal recovery, with the fourth model, based on our findings, presenting the best correlation between the real and recovered models. Seismicity in the study region is mainly correlated to low-velocity anomalies.

Uncertainty-Aware Deep Learning Methods for Robust Discrimination Between Earthquakes and Explosions

Geophysical Journal International - Thu, 08/07/2025 - 00:00
SummaryThe reliable classification of seismic events is crucial to precise seismic cataloging and robust hazard evaluation. Recent advances in deep learning have achieved great success in seismic event identification, leveraging their exceptional ability to automatically extract and recognize features. However, existing deep learning approaches to seismic classification rely exclusively on deterministic models, which cannot quantify epistemic uncertainty, preventing the estimation of prediction confidence that is critical for reliability evaluation. To address this issue, in this paper, we develop two uncertainty-aware deep learning models for earthquake (EQ) vs. explosion (EP) classification using the DiTing 2.0 artificial intelligence training dataset: a Bayesian convolutional neural network (BCNN) and a dropout-based CNN (DropCNN). We also implement a conventional deterministic CNN as a baseline model for comparative analysis. The experimental results demonstrate that both the BCNN and DropCNN can achieve a classification accuracy comparable to the conventional CNN, while providing additional uncertainty metrics for estimation confidence of prediction. Crucially, their uncertainty scores increase markedly in terms of encountering misclassifications or out-of-distribution samples compared to correct classifications, enabling automatic rejection of unreliable predictions based on the uncertainty threshold setting, triggering human verification or alternative discrimination methods. We then apply the trained models to analyze suspicious explosion events in the DiTing 2.0 dataset. The BCNN and DropCNN results exhibits strong agreement, consistently identifying 79 EP and two EQ events and flagging the remaining samples as uncertain classifications needing further verification. Our findings demonstrate that deep learning methods incorporating uncertainty estimation not only maintain a high accuracy in seismic event discrimination but also provide uncertainty estimation. This capability significantly enhances the model’s reliability and decision-making value in practical applications.

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