SummaryIntraplate earthquakes in stable continental regions exhibit diverse characteristics in terms of timing, spatial distribution, and magnitude. They are often unexpected, and their underlying physical mechanisms are not well understood. This complexity is particularly apparent in Norway, where seismicity is mostly localised on the continental margin and coastal areas. Various studies have attempted to explain the causes of seismicity in Norway by invoking different sources of stress, ranging from regional stress due to ridge push to local effects such as topography or deglaciation. In this study, we revisit these questions by investigating the distribution of seismicity in southwestern Norway using an enhanced earthquake catalogue. To achieve this, we revised the Norwegian National Seismic Network seismic catalogue from 2000 to 2023 and built a new catalogue using machine-learning-based techniques on data from a temporary seismic deployment in the region. Thanks to the increased station density during this deployment, we were also able to calculate new fault plane solutions that consistently showed a WNW-ESE direction for the most compressive axis. Furthermore, we demonstrate that seismicity in southwestern Norway, while diffuse, tends to be localised around the major crustal shear zones of the region, such as the Bergen Arc Shear Zone and the Hardangerfjord Shear Zone.
The Indiana Geological and Water Survey at Indiana University has been publishing critical research that addresses landslide risks across the Hoosier state. New high-resolution imagery and digital elevation measurements being collected by the Indiana Geographic Information Office will aid this work.
Five wildfires—the biggest of which are the Palisades and the Eaton fires—are still currently burning (as of 10 January 2025) in areas of north Los Angeles. At least 10 people are known to have lost their lives and many more properties have been burnt to the ground.
Oregon's Cascade Range mountains might not hold gold, but they store another precious resource in abundance: water. Scientists from the University of Oregon and their partners have mapped the amount of water stored beneath volcanic rocks at the crest of the central Oregon Cascades and found an aquifer many times larger than previously estimated—at least 81 cubic kilometers.
Researchers from the Hong Kong Polytechnic University, alongside mainland collaborators, have uncovered an unexpected phenomenon: severe wintertime ozone (O3) pollution in Lanzhou, China, driven primarily by alkene emissions from local petrochemical industries.
Plates at subduction zones typically move just a few centimeters per year. But when accumulated stress at these convergent plate boundaries releases suddenly, the plates can slip several meters and cause some of Earth's largest earthquakes. The timing and location of such megathrust earthquakes depend on factors such as the shape, roughness, composition, and fluid content of the fault.
Author(s): Daniel Plummer, Pontus Svensson, Dirk O. Gericke, Patrick Hollebon, Sam M. Vinko, and Gianluca Gregori
By performing an ensemble of molecular dynamics simulations, the model-dependent ionization state is computed for strongly interacting systems self-consistently. This is accomplished through a free energy minimization framework based on the technique of thermodynamic integration. To illustrate the m…
[Phys. Rev. E 111, 015204] Published Mon Jan 13, 2025
Abstract
In this paper, we propose a novel algorithm for fast frequency and phase synchronization of high-stability oscillators synchronized with 1 PPS signal from satellite navigation systems. The algorithm uses a model of a control object in the space of state variables and controls the frequency of an oscillator operating in a phase-locked loop. A new element is the introduction to the theoretical analysis and the design process, the time of entering synchronization. Currently, the literature lacks theoretical analysis and design methodology that considers the impact of the synchronization time on the choice of the steering algorithm and its parameters. All the data needed to determine the numerical values of the model were found experimentally for three different classes of control objects. Short synchronization times, a detailed description of the design methodology, and the use of values measured in the real system distinguish the proposed algorithm from the solutions described in the literature. The effect of optimization was achieved thanks to the algorithm’s two-stage operation. In the first stage, the algorithm aims to minimize the phase error quickly. The best solution for this stage is Sliding Mode Control (SMC). In the second stage, the algorithm strives to maximize the control quality, understood as minimizing the values of Maximum Time Interval Error (MTIE) and Time Deviation (TDEV). The Model Predictive Control (MPC) and Linear-Quadratic Regulator (LQR) optimal control algorithms were used at this stage. The paper also investigated the influence of the tuning parameters of these algorithms (weights as a function of cost) on the long-term behavior of the control system.
Nature Geoscience, Published online: 13 January 2025; doi:10.1038/s41561-024-01627-7
Space exploration has expanded the realm of geoscience to the outermost Solar System. A new generation of missions shines the way.
SummaryHaematite-bearing red beds are widespread across the Earth and play a pivotal role in palaeomagnetic studies. However, chemical remanent magnetisation (CRM) typically associated with authigenic haematite is not fully understood, which precludes more accurate interpretations of natural remanent magnetisation (NRM) in red beds. Here, we use electron microscopy, rock magnetism, and palaeomagnetism to investigate authigenic haematite in Early Triassic red beds in North China. Our findings reveal that the biotite-hosted haematite grains with grain sizes of several to tens of microns carry a significant portion of the NRM in these sedimentary rocks. We propose that these authigenic haematite particles primarily form during the early stages of diagenesis process. This authigenic haematite's growth is controlled by the crystal structure of the host biotite. Furthermore, this authigenic haematite displays high coercivity (> 100 mT) and high unblocking temperature (> 650 ° C), comparable to that of typical detrital haematite (30–1000 mT, > 650 ° C), which is usually the primary carrier of detrital remanent magnetisation (DRM) in such red beds. This study highlights the significance of combining mineralogical analysis with rock magnetism and palaeomagnetism to differentiate between CRM and DRM and thereby identify the primary NRM component within red beds. We hypothesize that the abundant iron supplied by biotite promotes the growth of authigenic haematite. This study illustrates the need to use caution when studying sedimentary NRM, particularly in rocks from source areas containing acidic igneous and metamorphic rocks (e.g. granite, diorite, and biotite gneiss) that contain a large proportion of iron-bearing minerals, such as the biotite observed in this study.
The micromechanics of friction has been investigated from the viewpoint of the healing of real contacts. In this study, the underlying processes of friction are discussed from the viewpoint of the contact junc...
Constraining the effective rheology of major faults contributes to improving our understanding of the physics of plate boundary deformation. Geodetic observations over the earthquake cycle are often used to e...
On February 8, 2022, approximately 40 of the 49 Starlink satellites were reported to have lost altitude, leading to atmospheric re-entry. SpaceX reported that the orbital decay on Starlink satellites was consi...
Melting ice sheets are often considered synonymous with climate change in the media, with evocative images of lone polar bears floating on ever-shrinking rafts of ice. While impacts such as sea level rise and salinity changes are commonly reported, one lesser-known consequence is the effect on volcanoes.
From the persistent droughts of southern Africa and Central America in the early part of the year to the more recent devastating extreme rainfall in Spain and the deadly Hurricane Helene along America's east coast, 2024 has been a year of climate events that affected the lives of billions of people.
Two of the ten most damaging earthquakes in recorded history happened on January 17th. This year is the thirtieth anniversary of Japan's Great Hanshin-Awaji Earthquake. The Northridge Earthquake in Southern California happened just one year earlier, in 1994. The two events killed 6,400 people, injured 45,000, and left a half million people homeless.
A new study led by scientists in the Schmid College of Science and Technology at Chapman University provides the first comprehensive global estimates of the amount of water stored in Earth's plants and the amount of time it takes for that water to flow through them. The information is a missing piece of the puzzle in understanding the global water cycle and how that cycle is being altered by changes in land use and climate.
A study based on the sampling and analysis of volcanic ash at Cumbre Vieja volcano in the Canary Islands, located off Africa's northwest coast, suggests that the composition of magma could drive tremors during volcanic eruptions.
Author(s): Vladimir I. Kolobov and Robert R. Arslanbekov
A hybrid kinetic-fluid model is used to study plasma stratification in alternating current (ac) discharges in noble gases at low plasma densities. Self-consistent coupled solutions of a nonlocal kinetic equation for electrons, a drift-diffusion equation of ions, and a Poisson equation for the electr…
[Phys. Rev. E 111, 015203] Published Fri Jan 10, 2025
A study published in Advances in Atmospheric Sciences has found that ocean warming in 2024 has led to new record high temperatures. The ocean is the hottest it has ever been recorded by humans, not only at the surface temperature but also for the upper 2000 meters.
