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A new study using data collected by NASA's Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite established a novel method to determine how productive plants are worldwide. The findings were published in IEEE Geoscience and Remote Sensing Letters.

SummaryThe Limpopo transform margin offshore southern Mozambique results from the separation of Gondwana along the East Africa continental margin. Over the last three decades, more than thirty different reconstruction models have been proposed, sometimes contradicting each other. Here, we present results from the travel-time tomography of wide-angle seismic data acquired during the second China-Mozambique Joint Cruise, allowing the interpretation of the crustal structure and magmatism in the Limpopo Corridor and the Mozambique Basin. Using these results, we determine the extent of the Continent Ocean Transition and the location of the Continent Ocean Boundary on the southern Mozambique margin. The seismic profile is 442-km long, extending from the eastern part of the North Natal Valley in the west and crossing the Limpopo Corridor and the Mozambique Basin to the east. Based on the tomographic velocity model, we delineated three distinct domains from west to east along the profile: (1) a western transitional domain with anomalous or mixed crust, bounded by the Mozambique Fracture Zone to the east, where the crust gradually thins eastward from ∼14 km at distance 45 km to ∼10.8 km at distance 140 km; (2) a domain of thickened oceanic crust resulting from enhanced magmatism, where the crust thins eastward, from ∼10.8 km to ∼8.5 km over ∼100 km distance; and (3) an eastern domain of normal oceanic crust, where the average crustal thickness is ∼8 km. We suggest that (1) the western transitional domain roughly corresponds to the Limpopo Corridor and is of continental crustal origin but was affected and modified by strike-slip motion and magmatic activity, resulting in anomalous or mixed crust. The eastern Continent Ocean Boundary of the Limpopo Margin is close to the Mozambique Fracture Zone; (2) The thickened oceanic domain thins eastward, and the crustal velocity and thickness change dramatically compared to the oceanic domain. This domain seems to have strongly interacted and contaminated by the Limpopo Corridor during the opening of Mozambique Basin and seafloor spreading; (3) The eastern oceanic domain shows a relatively uniform oceanic crust of ∼8 km and high velocity up to 7.4 km/s in the lower crust, suggestive of a hotter mantle that produces more MgO-rich melts probably due to the influence of a thermal mantle anomaly.

SummaryThe downward continuation of gravity field can provide valuable information for 3-D gravity-field modeling, shallow-layer geological interpretation, source depth estimation, and so on. However, downward continuation is ill-posed, and traditional approaches often suffer from computational instability, poor noise resistance, and limited continuation depth, making it a longstanding challenge in gravity data processing. We present a new approach for fast, stable and large-depth downward continuation of gravity anomalies by using frequency-domain 3-D imaging. First, we utilize the frequency-domain 3-D imaging approach to invert the gravity anomalies at the original observational plane to quickly obtain the equivalent density model in the subsurface. Then, we apply the optimized strategy of frequency-domain 3-D forward calculation on the equivalent density model to rapidly obtain high-precision gravity anomalies at the downward-continuation plane. The synthetic data tests prove the effectiveness of our approach, and demonstrate that our approach enables fast, stable, robust noise resistance and large-depth downward continuation of large-scale gravity anomalies data, and has superior performance compared to the traditional regularized filtering approach and spatial-domain equivalent-source approach. The real data test of the free-air gravity anomalies data in the central South China Sea also verifies the fast, stable and reliable downward continuations of large depths by our approach. The 3-D gravity-field model built by our approach will provide significant support for the tectonic studies and resource exploration in this area.

SummaryModelling and inversion of controlled-source electromagnetic data requires elaborate numerical tools. The major challenge is the high computational cost of computing solutions to numerous forward problems (for the forward responses as well as the sensitivity matrix). Forward modelling is accomplished using either a direct or an iterative solver. Current modelling suites predominantly employ direct solution methods in the forward operator since multiple solutions are easily accessible using inexpensive and quick forward-backward substitution after an initial resource-demanding matrix factorisation step. Iterative techniques, on the other hand, require little resources for single forward solutions, and are yet very time consuming if solutions for many right-hand sides are to be computed. Evaluations of different solution techniques for modelling and inverse problems are only sparsely investigated. In light of this, we integrated an iterative solver as alternative in the forward and and inversion operators of the open-source software custEM and pyGIMLi. In particular, we implemented a two-level iterative scheme where the outer solver employs a generalised conjugate residual algorithm preconditioned with a highly efficient block-based preconditioner for square blocks. The inner-level solver is either of the same type as the outer solver, but preconditioned with the auxiliary-space Maxwell preconditioner, or may alternatively be a direct solver. In this paper, we evaluate the described iterative forward operator for forward modelling tasks for the Marlim R3D model for a single as well as numerous right-hand side vectors and compare the performance to the direct solver MUMPS. We further investigate the solver’s applicability on small and medium-sized computing platforms. We then examine the iterative solver for inversions of synthetic land-based and semi-airborne data in terms of computational requirements. Our results demonstrate that forward modelling tasks are best performed using an iterative approach for single source problems. Moreover, simulations of large and complex problems are accessible on even on small computing platforms such as laptops in very reasonable time. For inversions, the iterative forward operator, in particular the mixed iterative-direct-based one, performs equally well in terms of time as the direct one while reducing the memory demands for the computations of the forward responses and the data sensitivities.

The Gulf of Maine—home to commercial fisheries for oysters, clams and mussels—has unexpectedly avoided an increase in seawater acidity, helping to preserve the health of its fisheries.

Editors’ Highlights are summaries of recent papers by AGU’s journal editors. Source: Geochemistry, Geophysics, Geosystems

More than a century ago, Alfred Wegener proposed that the Atlantic Ocean formed after North America drifted away from Africa and Eurasia. Much later, the theory of plate tectonics explained this movement as resulting from the formation of new oceanic crust in the space between the continents. But how did the the initial rift between the landmasses form, and how did it transition into a mid-ocean spreading ridge? Answers to these questions have remained elusive, partly because the time history of the rifting process has been difficult to decipher.

Foster-Baril et al. [2025] shed new light on the “rift to drift” transition by dating igneous rocks across a broad swath of the North American margin. They find that continental breakup and the subsequent transition to seafloor spreading was accomplished by three major pulses of magmatism. The first pulse was the largest, and involved extensive melting of mantle from below as the rift opened across a wide area. The second and third pulses, which were smaller, helped to localize the extensional deformation into a confined region. This localization facilitated the transition to symmetric seafloor spreading.

This sequence suggests that continental breakup happens across a much broader area, and over a longer time period, than was previously thought. It is still unclear if other continental breakup events also featured a series of magmatic pulses, or if the North American margin was unique in this way. Can this sequence also help us to understand “failed rifts” that never transition into seafloor spreading events? More studies that examine magmatism across broad regions of a rifting zone can help to answer such questions.

Citation: Foster-Baril, Z. S., Hinshaw, E. R., Stockli, D. F., Bailey, C. M., & Setera, J. (2025). Duration and geochemical evolution of Triassic and Jurassic magmatism along the Eastern North American Margin. Geochemistry, Geophysics, Geosystems, 26, e2024GC011900.  https://doi.org/10.1029/2024GC011900

—Clinton P. Conrad, Associate Editor, G-Cubed

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 earthquake near the east coast of the Kamchatka peninsula in Russia on July 30, 2025 generated tsunami waves that have reached Hawaii and coastal areas of the US mainland. The earthquake's magnitude of 8.8 is significant, potentially making it one of the largest quakes ever recorded.

Africa is a source of uncertainty in carbon cycle calculations. By some estimates, the continent's landscapes emit 2.1 billion tons more carbon dioxide than they take up each year—about equal to 1.5 times the annual emissions from coal-fired power plants. But other estimates are almost the complete opposite, suggesting that the continent's copious plant matter takes up 2.0 billion more tons of carbon dioxide per year than it releases.

In a world affected by climate change, the Southern Ocean plays an outsized role. It absorbs up to 40% of the human-caused emissions taken up by the oceans while also being home to some of the world's most vulnerable ecosystems.

A lot of the climate-altering carbon pollution humans release into the atmosphere by burning fossil fuels gets drawn into the Earth's oceans and landscapes through natural processes, mostly through photosynthesis, as plants turn atmospheric carbon dioxide into biomass.

Some of the rainiest places on Earth could see their annual precipitation nearly halved if climate change continues to alter the way ocean water moves around the globe.

Today at about 11:30am local time, a magnitude 8.8 earthquake struck off the coast of Russia's Kamchatka Peninsula in the country's far east.

Source: Global Biogeochemical Cycles

Africa is a source of uncertainty in carbon cycle calculations. By some estimates, the continent’s landscapes emit 2.1 billion tons more carbon dioxide than they take up each year—about equal to 1.5 times the annual emissions from coal-fired power plants. But other estimates are almost the complete opposite, suggesting that the continent’s copious plant matter takes up 2.0 billion more tons of carbon dioxide per year than it releases.

This uncertainty exists in part because the amount of carbon Africa takes up and emits varies greatly from year to year and partly because there is a dearth of available surface observations across the continent. Yun et al. investigated the reason for these fluctuations by applying a suite of atmospheric transport models to data from the Orbiting Carbon Observatory-2 (OCO-2), a satellite-borne instrument that tracks carbon dioxide emissions across Earth’s surface. By filling a critical observational gap over Africa, the OCO-2 satellite has allowed researchers to examine the continent’s carbon cycle in unprecedented detail.

Scientists previously suspected that temperature was the prime factor influencing plant growth and therefore carbon dioxide emissions. Instead, these researchers found that in Africa, moisture levels have a much bigger impact.

Different types of landscapes react to moisture quite differently, however. In shrublands and grasslands, plants take full advantage of water when it becomes available by increasing their mass with little energy expenditure. That reaction means that in wet years, shrublands and grasslands take up a lot of carbon and expel very little, substantially shifting the continent’s carbon flux. In contrast, forests and savannas emit and take up about the same amount of carbon in wet conditions; their overall impact on the continent’s carbon flux is therefore smaller.

These findings suggest an explanation for the long-standing question of why Africa was such a weak carbon sink during the El Niño event of 2015–2016. The continent was unusually dry during that time, leading to stalled plant growth and carbon uptake.

Rainfall is expected to change in Africa in the coming decades. Overall, moisture availability is expected to increase in the north and decrease in the south, but precipitation will likely be patchy, leading to discrete bursts of plant growth. The researchers emphasize that the long-term operation of OCO-2 is essential for monitoring how African ecosystems respond to these shifting rainfall patterns. Taking moisture fluctuations into account could enable more accurate predictions of how the carbon cycle will respond to climate change. (Global Biogeochemical Cycles, https://doi.org/10.1029/2025GB008597, 2025)

—Saima May Sidik (@saimamay.bsky.social), Science Writer

Citation: Sidik, S. M. (2025), When rain falls in Africa, grassland carbon uptake rises, Eos, 106, https://doi.org/10.1029/2025EO250277. Published on 30 July 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.

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.

One of the strongest earthquakes ever recorded struck off the eastern coast of Russia’s Kamchatka Peninsula Wednesday morning local time. Initially pegged at a magnitude-8.0, the quake was eventually upgraded to a magnitude-8.8. Adjusted magnitude estimates are not unusual for large earthquakes as more data become available.

If the estimate is not adjusted farther, the quake will be tied as the sixth largest earthquake ever recorded by modern instrumentation. The next largest instrumented event, a magnitude-9.0 quake, struck in 1952 roughly 45 kilometers to the northeast of the latest epicenter. 

U.S. Geological Survey “Did You Feel It?” reports captured the shaking that people on the Kamchatka Peninsula felt during the magnitude-8.8 earthquake. Credit: USGS, public domain

According to the U.S. Geological Survey (USGS), the recent earthquake likely struck along the Kuril-Kamchatka arc, which separates the Pacific tectonic plate and the Okhotsk microplate. Along the boundary, the Pacific plate is being subducted roughly to the west beneath the microplate. A preliminary USGS analysis of seismic data suggests the recent earthquake accommodated thrust motion, which is expected during slip along a subduction boundary.

On 20 July 2025, a magnitude-7.4 earthquake struck roughly 60 kilometers to the northeast of the recent epicenter. That quake occurred as a result of slip along a thrust fault of similar orientation. It’s proximity in location and time to the recent earthquake suggests the magnitude-7.4 quake was a foreshock to the magnitude-8.8 quake.  

Aftershocks are ongoing and will likely continue for weeks. More than 90 earthquakes of at least magnitude-4.4 have struck as of 1:00 p.m. UTC Wednesday, including a magnitude-6.9 shock followed a few minutes later by a magnitude-6.3 shock.

The magnitude-8.8 earthquake caused strong to extreme shaking in southern Kamchatka, according to USGS “Did You Feel It?” reports from the region.

 
Related

•  USGS Event Page: 2025 Kamchatka Peninsula, Russia Earthquake
•  U.S. Tsunami Warning Center
•  Japan Meteorological Agency Tsunami Warnings
 

The earthquake generated tsunami waves that spread across the Pacific. Wave heights of more than 3 meters inundated Severo-Kurilsk in the Kuril Islands south of Kamchatka, according to a Russian news agency.

The Japan Meteorological Agency issued tsunami warnings for much of the country’s Pacific coast. Waves up to 1.3 meters struck Kuji Port in northern Honshu. The U.S Tsunami Warning Center issued warnings for coastal Alaska, Hawaii, Washington, Oregon, and Northern California. Waves reached as high as 1.2 meters in Northern California. In Hawaii, waves reached 1.74 meters in Kahului on Maui and 1.5 meters in Hilo on the Big Island. 

Some injuries and no deaths have been reported.

—Jennifer Schmidt, Managing Editor

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 © 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.

Methane is a potent greenhouse gas with a much stronger short-term effect on warming than carbon dioxide. Over the near-term (20 years), 1 ton of methane has the warming effect of up to 84 tons of carbon dioxide, while over a hundred years, 1 ton of methane has the warming effect of about 28 tons of carbon dioxide. For this reason, controlling methane emissions is a high priority in limiting warming.

Recent climate-related crises—from severe storms and flooding to extreme heat—have raised new questions about how local governments communicate the risk of these crises and what they are doing to keep their citizens safe. To better understand what this communication looks like at local level, and the factors that may be shaping it, researchers from Drexel University analyzed climate resilience planning information available on the public-facing websites of 24 coastal communities in New Jersey that are contending with the effects of sea level rise.

Author(s): Yu-Xi Liu, Jin-Yue Geng, Hai-Xing Wang, Hao Yan, Xu-Hui Liu, Su-Rong Sun, Ao-wei Liu, and Tao Wu

Achieving uniform, stable, and reliable erosion of electrode materials is crucial for enhancing the performance and lifespan of vacuum-arc devices. This study investigates the rotation and erosion characteristics of cathode spots on Cu and Ti cathodes with various applied magnetic fields. The result…

[Phys. Rev. E 112, 015213] Published Wed Jul 30, 2025

A formidable new radar satellite jointly developed by the United States and India launched Wednesday, designed to track subtle changes in Earth's land and ice surfaces and help predict both natural and human-caused hazards.

A huge flood triggered by the rapid draining of a lake beneath the Greenland ice sheet occurred with such force that it fractured the ice above and burst out across its surface.

Wildfire season is no longer something that comes and goes; it's becoming a year-round concern. In BC, wildfires can shape the entire year, and we want to know what's coming, what's at risk and how to prepare.