Feed aggregator

Martian Magmas Live Long and Prosper

EOS - Thu, 04/10/2025 - 12:00

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

The longer a magma chamber resides in the upper crust, the more likely it will evolve to silica-rich compositions. Volcanism has been active on Mars throughout its history, but there is an apparent lack of widespread evolved magmatism, and the development of magma storage systems has been poorly constrained.

To better understand how crustal depth and temperature profile affect the evolution and growth of magma chambers on Mars, Chatterjee et al. [2025] utilize numerical modeling and compare with recent results from the InSight lander mission. Their models suggest that Mars’ crust is divided into three zones that are consistent with InSight seismic data: (1) the upper crust where small intrusions, such as dikes, dominate the upper crust; (2) the lower crust where larger magma chambers can develop and grow; and (3) a middle zone where magma chambers can occasionally grow and produce dikes that erupt at the surface.

The depths where the three magma storage zones are located depend on the crust’s temperature gradient and this study is the first to model the longevity of magma chambers on Mars as it has gradually cooled over geological time. A higher temperature gradient during Mars’ early history (the Noachian and Hesperian time periods) would have allowed larger, more long-lived upper crustal chambers to develop with the potential to feed eruptions at the surface. Seismic activity in Cerberus Fossae detected by InSight is consistent with magmatism and suggests its continued influence on the structure and make-up of the crust of Mars.

Citation: Chatterjee, A. P., Huber, C., Head, J. W., III, & Bachmann, O. (2025). Magma chamber longevity on Mars and its controls on crustal structure and composition. Journal of Geophysical Research: Planets, 130, e2024JE008798. https://doi.org/10.1029/2024JE008798

—Mariek E. Schmidt, Associate Editor, JGR: Planets

Text © 2024. 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.

Enhanced terahertz emission from the wakefield of ${\text{CO}}_{2}$-laser-created plasma

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

Author(s): Srimanta Maity and Garima Arora

High-field terahertz (THz) pulse generation is investigated through the interaction of an intense single-color CO2 laser pulse with helium (He) gas targets. Employing particle-in-cell (PIC) simulations, this study reveals a substantial enhancement in THz generation efficiency, even with a single-col…

[Phys. Rev. E 111, 045205] Published Thu Apr 10, 2025

The 8 May 2022 Baiyan rock avalanche in Guizhou, China

EOS - Thu, 04/10/2025 - 07:52

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

On 8 May 2022, the catastrophic Baiyan rock avalanche occurred in Zhijin County, which is located in Guizhou Province, China. The digital lat/long is [26.63771, 105.69200]. I described this event at the time (on the old AGU blogsite). It destroyed 53 houses, killing three people.

Intriguingly, many of the reports of this event seem to have been removed, such as the 163.com news item and the Youtube video. This is the image of the failure that I posted at the time:-

The 8 May 2022 Baiyan rock avalanche in Bijie, Guizhou. Image from 163.com.

There is a very interesting new paper (He et al. 2025) about this event in the journal Landslides. The aim of the paper is to examine the behaviour of the particles that formed the rock avalanche using a very impressive combination of a drone survey and articial intelligence driven analysis of individual particles. This is fascinating work, which demonstrates that underlying topography plays a large role in determining the runout characteristics of individual blocks.

But along the way, the paper also provides some very interesting information about the Baiyan rock avalanche itself. First, the slope from which this failure occurred had suffered an astonishing total of seven other rock avalanches in the period between 2019 and 2022. The Google Earth image below, from March 2022 (i.e. before the Baiyan rock avalanche) shows the problems that were occurring on the slope:-

Google Earth image of the site of the 8 May 2022 Baiyan rock avalanche in China.

According to He et al. (2025), the Baiyan rock avalanche itself had a volume of 36,000 cubic metres. It had a runout distance of about 560 metres and a vertical height difference of about 455 m. Significant, but not exceptional, rainfall occurred in the days leading up to the collapse.

Tucked away towards the end of the article is a fascinating consideration of the causes of this event, and of the extraordinary cluster of failures that occurred in this area at the time. Underground coal mining was being undertaken directly below this slope – He et al. (2025) show that a panel advanced from the SW to the NE directly below the ridgeline, starting in the southwest in October 2021. In May 2022, the mining activities were occurring directly below the source area of the Baiyan rock avalanche. The implication is clearly that disturbance / subsidence caused fracturing of the rock mass, triggering the failure.

That comparatively shallow coal mining was occurring directly below such a sensitive location is perhaps surprising. This should be a classic case study of the impacts of poorly controlled mining on slope stability. I also wonder why the village was not evacuated before the landslide given the multiple failures that were occurring on the slope directly behind. It would be interesting to know more about the analyses and discussions that were occurring at this location in the early months of 2022.

Reference

He, J., Zhang, Y., Sun, P. et al. 2025. Investigation of deposition characteristics using a novel super-resolution method: a case study of Baiyan rock avalanche in Guizhou, China. Landslides. https://doi.org/10.1007/s10346-025-02512-z

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.

Multi-Station Seismic Location via Machine Learning: Application to Oklahoma and Southern California

Geophysical Journal International - Thu, 04/10/2025 - 00:00

SummaryLocating earthquakes plays an important role in the study of seismic activity and geological structures. Traditional methods for locating earthquakes mainly rely on waveform matching and travel time fitting. With the development of artificial intelligence technology, machine learning methods have often been applied to locate earthquakes. However, current machine learning approaches may face challenges related to physical constraints. In this study, we build a 3D U-Net network with station distribution constraints to locate earthquakes. To improve the generalizability of the network model, we apply data augmentation techniques, including data shifting, selection, rotation, and fusion. The location results are evaluated using a testing dataset from Oklahoma, showing an average location error of about 5 km. The origin time can be determined based on the earthquake's location and the waveforms recorded by stations through waveform shifting and stacking. This method does not require the complex processing steps of traditional seismic approaches, allowing for rapid earthquake location. Additionally, we apply the network model to data recorded in Southern California through transfer learning for further application. The results show that this new method is stable and generalized, making it applicable to earthquake location problems associated with arbitrary station networks. Furthermore, we discuss the effects of data augmentation, network architecture, and the Gaussian radius of labels on the outcomes. These insights help us better understand machine learning algorithms and improve the application of deep learning in earthquake location.

Navigating the space of seismic anisotropy for crystal and whole-Earth scales

Geophysical Journal International - Thu, 04/10/2025 - 00:00

SummaryEvidence of seismic anisotropy is widespread within the Earth, including from individual crystals, rocks, borehole measurements, active-source seismic data, and global seismic data. The seismic anisotropy of a material determines how wave speeds vary as a function of propagation direction and polarization, and it is characterized by density and the elastic map, which relates strain and stress in the material. Associated with the elastic map is a symmetric 6 × 6 matrix, which therefore has 21 parameters. The 21-dimensional space of elastic maps is vast and poses challenges for both theoretical analysis and typical inverse problems. Most estimation approaches using a given set of directional wavespeed measurements assume a high-symmetry approximation, typically either in the form of isotropy (2 parameters), vertical transverse isotropy (radial anisotropy: 5 parameters), or horizontal transverse isotropy (azimuthal anisotropy: 6 parameters). We offer a general approach to explore the space of elastic maps by starting with a given elastic map T. Using a combined minimization and projection procedure, we calculate the closest Σ-maps to T, where Σ is one of the eight elastic symmetry classes: isotropic, cubic, transverse isotropic, trigonal, tetragonal, orthorhombic, monoclinic, and trivial. We apply this approach to 21-parameter elastic maps derived from laboratory measurements of minerals; the measurements include dependencies on pressure, temperature, and composition. We also examine global elasticity models derived from subduction flow modeling. Our approach offers a different perspective on seismic anisotropy and motivates new interpretations, such as for why elasticity varies as a function of pressure, temperature, and composition. The two primary advances of this study are 1) to provide visualization of elastic maps, including along specific pathways through the space of model parameters, and 2) to offer distinct options for reducing the complexity of a given elastic map by providing a higher-symmetry approximation or a lower-anisotropic version. This could contribute to improved imaging and interpretation of Earth structure and dynamics from seismic anisotropy.

KVP: A multiscale kurtosis approach for seismic phase picking

Geophysical Journal International - Thu, 04/10/2025 - 00:00

SummaryAutomatic event detection and phase picking are critical for processing the large volumes of data produced by modern seismological instrumentation. Accurate picking is especially challenging in Distributed Acoustic Sensing (DAS) recordings, where data quality can significantly vary along segments of the fiber due to localized environmental noise and coupling issues, reducing signal-to-noise ratios (SNR). Similarly, Ocean Bottom Seismometer (OBS) data quality also suffers from these issues. To improve accuracy under diverse conditions, we developed a novel multiband kurtosis-based picking algorithm, Kurtosis-Value-Picker (KVP), that enhances phase picking for both impulsive and emergent seismic signals. Our approach uses characteristic functions (CFs) calculated with sliding windows across multiple frequency bands. Triggers are identified based on localized kurtosis jumps over a few samples, providing greater sensitivity to emergent signals than traditional finite-difference methods. Each individual CF has its own set of triggers, adding flexibility to phase picking and retaining spectral information. We validate the KVP algorithm using earthquake data recorded with DAS on two land and submarine fiber-optic cables, as well as OBS data. We also compare its performance with a widely-cited, kurtosis-based algorithm, the widely-used FilterPicker algorithm, and the well-known PhaseNet model, using impulsive signals on nearby DAS channels as a ground truth for emergent arrivals. Our results demonstrate that KVP provides accurate picks and is suitable for complex seismic datasets.

U.S. National Climate Assessment Likely Dead After Contract Canceled

EOS - Wed, 04/09/2025 - 19:26

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

The Trump administration has canceled funding used to coordinate the National Climate Assessment, a major, congressionally mandated U.S. climate change report produced through the U.S. Global Change Research Program (USGCRP).

The National Climate Assessment is published approximately every four years and is the United States’ broadest assessment of current climate change impacts and climate science.

NASA canceled a contract with ICF International, a consulting firm. ICF International was hired by the agency to support USGRCP’s logistical work and help coordinate the expansive assessment, which involves input from 15 federal agencies and hundreds of authors and contributors.

ICF previously supported the development and release of the Fifth National Climate Assessment and the Fourth National Climate Assessment.

The change likely means the Sixth National Climate Assessment, planned for publication by early 2028, won’t be completed.

I can't say this was unexpected, but it is deeply, deeply disappointing nonetheless. The #NCA6 is now up in the air – at best.Some problems go away on their own. This is not one of them.It is coming. It's already here. You can either be prepared or unprepared.

— Cullen Hendrix (@cullenhendrix.bsky.social) 2025-04-09T16:15:43.477Z

Congress requires the Sixth National Climate Assessment to move forward, but federal officials involved in USGCRP work told Politico that the assessment is likely dead without the support of ICF International staff. Two dozen staff at the USGCRP will lose the funding to support their roles, Science reported.

The move is not a surprise to those who have been following Trump’s actions on climate change. Russell Vought, the current director of the Office of Management and Budget for the Trump administration, has previously recommended ditching the National Climate Assessment and firing scientists who worked on previous editions of the report.

The cuts come alongside other efforts from the Trump Administration to undermine climate change research including cutting funding to cooperative agreements between U.S. universities and federal agencies to study Earth systems and climate change.

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

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2024. 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.

Sink or swim: The fate of sinking tectonic plates depends on their ancient tectonic histories

Phys.org: Earth science - Wed, 04/09/2025 - 19:19

Newly published research has revealed that compositional rock anomalies within oceanic plates caused by ancient tectonics influence the trajectory and speed of the plates as they plunge deep into Earth's mantle.