A new study published in Advances in Atmospheric Sciences sheds light on the complex relationship between methane emissions and the recovery of the stratospheric ozone layer. The research underscores how future increases in methane emissions could significantly influence ozone recovery, particularly in the polar regions.
At first glance, landscapes like the Great Plains and the Rockies may seem unchanging, but over geological time scales, they're dynamic systems. Plate tectonics raise mountains, while erosion—driven by glaciers, rain and wind—wears them down. But there's an often-overlooked factor in this process: the rock itself.
A new seismic study of Singapore could guide urban growth and renewable energy development in the coastal city nation, where 5.6 million residents live within an area of 734 square kilometers.
Some parts of Hawaii are sinking faster than others. That discovery, published in Communications Earth & Environment by researchers at the University of Hawaii (UH) at Mānoa, also highlights that as sea level rises, the infrastructure, businesses, and communities in these low-lying areas are at risk of flooding sooner than scientists anticipated, particularly in certain urban areas of O'ahu.
Hydrothermal alteration is a complex geological process that can later serve as an indicator of gold deposits for mineral explorers. The process sees hot and metal-rich fluids interact with surrounding rocks, causing chemical and mineralogical changes.
A type of artificial intelligence that mimics the functioning of the human brain could represent a powerful solution in automatically detecting wildfires, plummeting the time needed to mitigate their devastating effects, a new study finds.
Author(s): Louis Jose, James C. Welch, III, Timothy D. Tharp, and Scott D. Baalrud
Strongly magnetized plasmas, characterized by having a gyrofrequency larger than the plasma frequency (β=ωc/ωp≫1), are known to exhibit novel transport properties. Previous works studying pure electron plasmas have shown that strong magnetization significantly inhibits energy exchange between parall…
[Phys. Rev. E 111, 035201] Published Thu Mar 06, 2025
SummaryThe Central African Plateau records multiple stages of continental extension and assembly between the Congo and Kalahari cratons in south-central Africa. Of significant interest is the formation of the Neoproterozoic Katangan Basin which was subsequently closed during the Pan-African assembly of Gondwana — a region that contains some of the world’s largest sediment-hosted copper and cobalt deposits. Whether Katangan Basin development only involved continental extension or progressed to incipient sea-floor spreading is uncertain; so too the extent to which mafic magmatism has modified bulk-crustal structure. Also debated is whether crustal re-working during overprinting by the Pan-African Orogeny to form the Lufilian Arc, was localised or broadly distributed across the entire Katangan Basin. To address these questions, we calculate crustal thickness (H) and bulk-crustal VP/VS ratio (κ) using H-κ stacking of teleseismic receiver functions recorded by seismograph networks situated across the Central African Plateau, including the new Copper Basin Exploration Science (CuBES) network. Crustal thickness is 45–48 km below the Congo Craton margin, Mesoproterozoic Irumide belt, and Domes region of the Lufilian Arc, 38–42 km below the Bangweulu Craton and 35–40 km below the Pan-African Zambezi Belt in southeastern Zambia. Bulk-crustal VP/VS is generally low (<1.76) across the majority of the Plateau, indicating a dominantly felsic bulk-crustal composition. The formation of the Katangan Basin in the Neoproterozoic is thus unlikely to have been accompanied by voluminous mafic magmatism, significant lower crustal intrusions and/or the formation of oceanic crust. The early-Paleozoic overprinting of the basin by the Pan-African Orogeny, forming the Lufilian Arc, appears to have been most intense in the Domes region, where a deep and highly variable (38–48 km) Moho topography at short length-scales (<100 km), is evident in our H-κ stacking results. In contrast, shallow and flat Moho architecture with consistently low bulk crustal VP/VS ratios, are observed further south. This flat region includes the Mwembeshi Shear Zone, which is also not associated with a VP/VS ratio contrast, suggesting the fault likely separates two very similar crustal domains.
SummaryEarthquake cycle modelling is critical to help us understand the underlying physical mechanisms of earthquake processes. However, it is a very challenging scientific problem because of the variety of spatial and temporal scales involved in fault friction behaviour. Scholars have researched this problem based on different numerical methods, but there is still an urgent need to develop more rigorous and robust numerical methods. We construct a new finite-difference operator to approximate the variable-coefficient second derivatives by combining the central-difference method with the equivalent medium parametrisation method. Using the method of manufactured solutions, we perform rigorous convergence tests, and the results show that the new finite-difference operator achieves second-order convergence. We use this new method in 2D earthquake cycle simulation and the geometric multi-grid method as an iterative solver to accelerate the computation while optimising the code on a GPU platform to improve computational efficiency further. We simulate the earthquake sequences on a vertical fault in homogeneous and heterogeneous basin models using our method and SCycle, respectively. The comparison of results shows good agreement. Our method can be utilised to study the long-term slip histories of large-scale faults in complicated mediums, as demonstrated by these results.
SummaryAs seismic imaging moves towards the imaging of more complex media, properly modelling elastic effects in the subsurface is becoming of increasing interest. In this context, elastic wave conversion, where acoustic, pressure (P-) waves are converted into elastic, shear (S-) waves, is of great importance. Accounting for these wave conversions, in the framework of forward and inverse modelling of elastic waves, is crucial to creating accurate images of the subsurface in complex media. The underlying mechanism of wave conversion is well understood and described by the Zoeppritz equations. However, as these equations are highly non-linear, approximations are commonly used. The most well-known of these approximations is Shuey’s approximation. However, this approximation only holds for small angles and small contrasts, making it insufficient for realistic forward and inverse modelling scenarios, where angles and contrasts may be large. In this paper we present a novel set of approximations, based on Taylor expansions of the Zoeppritz equations, which we name the extended Shuey approximations. We examine the quality of these approximations to the Zoeppritz equations and compare them to existing approximations described in literature. We then apply these extended Shuey approximations to the elastic Full-Wavefield Modelling algorithm for a simple, synthetic, 1.5D example, where we show that we can accurately model the P- and S-wavefields in a forward modelling case. Finally, we apply our approximations to the elastic Full-Wavefield Migration algorithm for a simple, synthetic, 1.5D example, where we show that we can recover an accurate image in an inverse modelling case.
Whether it's rivers cutting through earth, lava melting through rock, or water slicing through ice, channels all twist and bend in a seemingly similar back-and-forth manner. But a new study led by scientists at The University of Texas at Austin has discovered that channels carved by rivers actually have curves distinct to those cut by lava or ice.
Iron oxide minerals are found in rocks around the globe. Some are magnetic, and some of them rust—especially when exposed to water and oxygen. These characteristics provide clues about the history of these minerals.
On the abyssal plains, at depths between 3,000 and 6,000 meters, polymetallic nodules are scattered across millions of square kilometers, much like potatoes in a field. These mineral ores are formed over millions of years from metals dissolved in the ocean water or released during microbial degradation of organic material in the sediments. As global demand for critical metals, such as nickel, cobalt, and copper, grows, so too does the pressure to exploit these resources economically.
A new MIT-led study confirms that the Antarctic ozone layer is healing, as a direct result of global efforts to reduce ozone-depleting substances.
Sand underpins everything from skyscrapers to smartphones. Sharp sand (as opposed to rounded desert sand) is the key ingredient in concrete, while high-purity silica sand is essential for making the silicon chips that power our digital devices.
For decades, scientists assumed that only large ocean temperature patterns covering 200 kilometers (124 miles) or more could strongly influence storms. Now, by leveraging advances in computing power, a team of scientists from UC San Diego's Scripps Institution of Oceanography, NASA Jet Propulsion Laboratory and NASA Goddard Space Flight Center have discovered that small-scale ocean processes can have a much larger influence on storm development than previously thought.
New research has uncovered why different climate models offer varying projections of sea surface temperature (SST) changes in the tropical Pacific, a region critical for global climate patterns. The study, published in Advances in Atmospheric Sciences, identifies cloud–radiation feedback as the dominant source behind these differences.
SummaryOn 22 January 2024, a MW 7.0 earthquake struck the southern sector of the Tian Shan Mountains in Wushi County, northwestern China, causing damage and casualties. In this study, using Interferometric Synthetic Aperture Radar (InSAR) measurements (Sentinel-1 satellites), we constrained the geometry of the fault segment responsible for the seismic event, the coseismic slip distribution, and the source of the subsequent MW 5.7 aftershock deformation. Finally, we evaluated the potential state of stress of the unruptured portions of the causative fault as well as of adjacent fault segments, using the Coulomb stress failure function variations. Our findings indicate rupture along a transpressive left-lateral NNW dipping high-angle fault, associated with the Southern Tian Shan Fault (STF) alignment, likely the Maidan fault, with slip up to 3.5 m only occurring between 10 and 20 km depth. The position of the hypocenter with respect to our estimated slip distribution supports the evidence of a marked bilateral ENE-WSW rupture directivity during the mainshock. The modeling of the postseismic deformation that includes the MW 5.7 aftershock occurred on 29 January 2024, and that is located about 15 km to the south of the mainshock, indicates a main patch with up to 90 cm of slip that may have occurred on a shallow back-thrust segment, in agreement with the observed surface breaks. We propose a potential structural and/or lithological influence on the coseismic rupture extent, consistent with observations from other intracontinental earthquakes. Finally, based on the Coulomb stress distribution computation, we find that the MW 5.7 aftershock was likely triggered by the preceding mainshock and that the Wushi earthquake also increased the stress level at both terminations of the modeled fault plane, particularly along the southwestward continuation of the Maidan fault. In addition, we also find that a wide up-dip fault patch remained unruptured, and considering that these areas have been dynamically loaded it could represent potential further aseismic deformation and/or future significant ruptures, posing a continuing seismic hazard to Wushi County and surroundings areas.
Northwestern University researchers are actively overturning the conventional view of iron oxides as mere phosphorus "sinks." A critical nutrient for life, most phosphorus in the soil is organic—from remains of plants, microbes or animals. But plants need inorganic phosphorus—the type found in fertilizers—for food.
The overall amount of carbon dioxide in the atmosphere has been steadily increasing, a clear trend linked to human activities and climate change. Less concerning but more mysterious, the difference between the highest and lowest amounts of carbon dioxide in the atmosphere each year has also been increasing.
