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Joint Reprocessing Method of Multi-Vintage Shipborne Gravity Anomalies Considering Temporal Error Effects: A Case Study of the Philippine Sea

Geophysical Journal International - Mon, 07/21/2025 - 00:00
SummaryShipborne gravity anomaly data exhibit multi-vintage characteristics due to their extended temporal coverage. Currently, the measurement accuracy of gravimeters and the processing methods for shipborne gravity anomaly data have been significantly improved and refined. At this stage, the influence of temporal error on the processing of shipborne gravity anomaly data has become an issue that cannot be neglected. We propose a joint reprocessing method for multi-vintage shipborne gravity anomaly data considering temporal error effects. Firstly, the gross error of the shipborne gravity anomaly data is eliminated and filtered. When compensating for the survey line error, the time variable is added to the error equation in order to retain the temporal information in the observed value. The corrected shipborne gravity anomaly data by this method is closer to the real gravity field information. We applied this method to the real shipborne gravity anomaly data in the Philippine Sea. The results showed that the standard deviation of the discrepancy at the intersection points of the survey lines was reduced from the initial 13.46 mGal to 4.30 mGal. The shipborne gravity anomaly data processed after considering the temporal error effects conforms more closely to the actual gravity field information.

We detected deep pulses beneath Africa—what we learned could help us understand volcanic activity

Phys.org: Earth science - Sun, 07/20/2025 - 14:50
Earth's continents may look fixed on a globe, but they've been drifting, splitting and reforming over billions of years—and they still are. Our new study reveals fresh evidence of rhythmic pulses of molten rock rising beneath east Africa, reshaping our understanding of how continents break apart.

Restoring sea floor after mining may not be possible, researchers warn

Phys.org: Earth science - Sun, 07/20/2025 - 13:59
Scientists present at the latest effort to hash out international rules for deep-sea mining say it's unclear if it's possible to restore damaged seafloor ecosystems—or how long it would take.

Dead Sea's salt giants reveal how massive salt deposits form over time

Phys.org: Earth science - Sat, 07/19/2025 - 11:40
The Dead Sea is a confluence of extraordinary conditions: the lowest point on Earth's land surface, with one of the world's highest salinities. The high concentration of salt gives it a correspondingly high density, and the water body's status as the deepest hypersaline lake gives rise to interesting and often temperature-related phenomena below the water's surface that researchers are still uncovering.

Machine learning uncovers 10 times more earthquakes in Yellowstone caldera

Phys.org: Earth science - Sat, 07/19/2025 - 11:31
Yellowstone, a popular tourist destination and namesake of an equally popular TV show, was the first-ever national park in the United States. And bubbling beneath it—to this day—is one of Earth's most seismically active networks of volcanic activity.

Myanmar earthquake's fault rupture exceeded seismic wave speeds, offering rare evidence of supershear

Phys.org: Earth science - Sat, 07/19/2025 - 11:27
The first studies of the 28 March 2025 magnitude 7.8 Myanmar earthquake suggest that the southern portion of its rupture occurred at supershear velocity, reaching speeds of 5 to 6 kilometers per second.

Deep life's survival secret: Crustal faulting generates key energy sources, study shows

Phys.org: Earth science - Fri, 07/18/2025 - 18:00
Chinese researchers have recently challenged the long-held belief that "all life depends on sunlight." In a study published in Science Advances, the researchers identified how microbes in deep subsurface areas can derive energy from chemical reactions driven by crustal faulting, offering critical insights into life deep below Earth's surface.

Ecosystem collapse patterns mirror magnetic material behavior under stress

Phys.org: Earth science - Fri, 07/18/2025 - 15:50
A new study published in the journal One Earth reveals that the way ecosystems collapse—abruptly or gradually—may depend on internal complexity, much like how magnetic materials behave under stress.

How Google's Android earthquake detection system can save lives

Phys.org: Earth science - Fri, 07/18/2025 - 14:00
If you're in an earthquake-prone area and own an Android phone, it could save your life. It may even have already done so. The Android Earthquake Alert (AEA) system, which began in the U.S. in 2020 and has since expanded globally, sends an automatic alert approximately one minute before the ground starts shaking. That can be enough time to take cover or warn others nearby.

Artificial Light Lengthens the Urban Growing Season

EOS - Fri, 07/18/2025 - 12:00

Artificial light and higher temperatures in cities may lengthen the growing season by up to 24 days, according to a new study in Nature Cities.

Previous studies have observed that plant growth starts earlier and ends later in cities than in rural areas. But these studies haven’t concluded whether this difference depends more on heat or light, both of which regulate the growing season and are amplified in urban centers.

The new study’s authors used satellite data to estimate nighttime light pollution in cities and pinpoint the start and end of the growing season. They found that the amount of artificial light at night plays a bigger role in growing season length than temperature does, especially by delaying the end of the season.

“This study highlights artificial light at night as a powerful and independent force on plant phenology,” said Shuqing Zhao, an urban ecologist at Hainan University in China who was not involved in the research. “It marks a major step forward in our understanding of how nonclimatic urban factors influence plant life cycles.”

City Lights Trick Plants

“Plants rely on both temperature and light as environmental cues to regulate their growth,” explained Lin Meng, an environmental scientist at Vanderbilt University and a coauthor of the study. In the spring, warmer temperatures and lengthening days signal to plants that it’s time to bud and produce new leaves. In the fall, colder, shorter days prompt plants to drop their leaves and prepare for winter.

“Plants evolved with predictable cycles of light and darkness—now, cities are flipping that on its head.”

But in cities, these essential cues can be disrupted. Cities are typically hotter than surrounding rural areas—the so-called urban heat island effect—and much brighter because of the abundance of artificial light. These disrupted cues “can trick plants into thinking the growing season is longer than it actually is,” Meng said. “Plants evolved with predictable cycles of light and darkness—now, cities are flipping that on its head.”

To assess how heat and light are affecting urban plants, Meng and her coauthors used satellite data from 428 cities in the Northern Hemisphere, collected from 2014 to 2020. For each city, the researchers analyzed correlations between the amount of artificial light at night (ALAN), air temperature, and the length of the growing season.

The scientists found that on average, the growing season started 12.6 days earlier and ended 11.2 days later in city centers compared with rural areas. ALAN apparently played an important role in extending the growing season, especially in the autumn, when ALAN’s influence exceeded that of temperature.

Anna Kołton, a plant scientist at the University of Agriculture in Krakow who was not part of the research, highlighted the significance of this result. “The impact of climate change, including increased temperatures on plant functioning, is widely discussed, but light pollution is hardly considered by anyone as a significant factor affecting plant life.” The new study is among the first to bring ALAN’s effects into the spotlight.

“Every Day Needs a Night”

“The extension of urban vegetation may at first glance appear positive,” said Kołton. But this positive impression is deceiving. In reality, an extended growing season “poses a threat to the functioning of urban greenery.”

Delaying the end of the growing season may be especially disruptive. In the fall, shortening days prompt plants to reduce their metabolic activity, drop their leaves, and toughen up their cell walls to withstand the coming winter. But if they are constantly stimulated by artificial light, Kołton pointed out, urban plants may miss their cue and be unprepared when the cold hits.

“Every day needs a night, and so do our trees, pollinators, and the rhythms of nature we all depend on.”

Longer growing seasons also affect animals and people. “Flowers might bloom before their pollinators are active, or leaf-out might not align with bird migration,” said Meng. “And for people, a longer growing season means earlier and prolonged pollen exposure, which can make allergy seasons worse.”

As cities become bigger and brighter, their growing seasons will likely continue to lengthen unless the impacts of ALAN are addressed. “The good news is that unlike temperature, artificial light is something we can manage relatively easily,” said Meng. She and Zhao both suggested that swapping blue-rich LED lamps for warmer LEDs (which are less stimulating to plants), introducing motion-activated or shielded lights, and reducing lighting in green spaces could limit light pollution in cities.

“Every day needs a night,” Meng said, “and so do our trees, pollinators, and the rhythms of nature we all depend on.”

—Caroline Hasler (@carbonbasedcary), Science Writer

Citation: Hasler, C. (2025), Artificial light lengthens the urban growing season, Eos, 106, https://doi.org/10.1029/2025EO250254. Published on 18 July 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.

Multi-stage Deep Clustering of Urban Ambient Noise for Seismic Imaging - A Case Study for Train-Induced Seismic Noise

Geophysical Journal International - Fri, 07/18/2025 - 00:00
SummaryPassive surface wave method is increasingly being applied to urban subsurface exploration due to its non-invasiveness, low cost, and high efficiency. However, its imaging quality is often influenced by limited data acquisition time and the heterogeneous distribution of seismic ambient fields in complex urban environments. To extract coherent surface wave signals for seismic imaging in such challenging setting, we developed a multi-stage urban ambient noise deep clustering framework based on a convolutional autoencoder and deep embedded clustering algorithm. The initial clustering characterizes the distribution patterns of urban noise sources, which informs a secondary, finer clustering to select noise sources optimized for urban seismic imaging. Real-world experiment on the urban train noise field demonstrates our urban noise cluster framework effectively identifies and elucidates the temporal evolution patterns of moving train sources. Compared to traditional data selection methods, our approach yields superior dispersion measurements and significantly attenuates artifacts from the fundamental mode. Furthermore, by employing mode-specific clustering, we successfully capture the refined first overtone, enhancing the accuracy and depth resolution of seismic imaging. This study presents a new perspective to analyzing and selecting complex noise sources, significantly advancing seismic imaging and monitoring in alignment with emerging Artificial Intelligence trends.

Fully-dynamic seismic cycle simulations in co-evolving fault damage zones controlled by damage rheology

Geophysical Journal International - Fri, 07/18/2025 - 00:00
SummaryBoth short-term coseismic off-fault damage and long-term fault growth during interseismic periods have been suggested to contribute to the formation and evolution of fault damage zones. Most previous numerical models focus on simulating either off-fault damage in a single earthquake or off-fault plasticity in seismic cycles ignoring changes of elastic moduli. Here we developed a new method to simulate the damage evolution of fault zones and dynamic earthquake cycles together in a 2D anti-plane model. We assume fault slip is governed by the laboratory-derived rate-and-state friction law while the constitutive response of adjacent off-fault material is controlled by a simplified version of the Lyakhovsky-Ben-Zion continuum brittle damage model. This study aims to present this newly developed modeling framework which opens a window to simulate the co-evolution of earthquakes and fault damage zones. We also demonstrate one example application of the modeling framework. The example simulation generates coseismic velocity drop as evidenced by seismological observations and a long-term shallow slip deficit. In addition, the coseismic slip near the surface is smaller due to off-fault inelastic deformation and results in a larger coseismic slip deficit. Here we refer to off-fault damage as both rigidity reduction and inelastic deformation of the off-fault medium. We find off-fault damage in our example simulation mainly occurs during earthquakes and concentrates at shallow depths as a flower structure, in which a distributed damage area surrounds a localized, highly damaged inner core. With the experimentally based logarithmic healing law, coseismic off-fault rigidity reduction cannot heal fully and permanently accumulates over multiple seismic cycles. The fault zone width and rigidity eventually saturate at long cumulative slip, reaching a mature state without further change.

Weaker Atlantic currents bring more oxygen to tropical ocean's shallow depths

Phys.org: Earth science - Thu, 07/17/2025 - 14:51
How is ventilation at various depth layers of the Atlantic connected and what role do changes in ocean circulation play? Researchers from Bremen, Kiel and Edinburgh have pursued this question and their findings have now been published in Nature Communications.

Machine Learning Model Flags Early, Invisible Signs of Marsh Decline

EOS - Thu, 07/17/2025 - 13:24

A computer model drawing on satellite and climate data could give scientists an early warning of coastal marsh decline.

Using the model, scientists detected a decline in underground plant biomass across much of Georgia’s coastal marshes between 2014 and 2023. Critically, this loss occurred even though the marsh grasses appeared green and thriving at the surface.

The findings, published last month in Proceedings of the National Academy of Sciences of the United States of America, could help land managers identify targets for restoration before more severe damage takes hold.

Roots of Concern

Marshes “are not only economically but culturally and recreationally important places for the people who both live along the coast and visit the coast.”

Marshes “are not only economically but culturally and recreationally important places for the people who both live along the coast and visit the coast,” said study coauthor Kyle Runion, a landscape ecologist at the University of Georgia. They help control flooding, sequester carbon, and provide space for hunting, fishing, and wildlife spotting.

But rapid sea level rise has threatened coastal marsh grasses, as higher waters and more frequent flooding inundate the soil and choke oxygen supply at the roots. In a healthy ecosystem, underground plant biomass staves off erosion and adds organic matter that eventually decomposes into more soil, boosting the marsh’s resilience to sea level rise, so declining root systems can be an early sign of trouble in marshlands.

Marshlands can appear healthy even as their roots are dying off, said Bernard Wood, a wetland ecologist at the Coastal Protection and Restoration Authority of Louisiana who was not involved in the study.

A trip into the marsh itself tells a different story, however. “You could just pick up this huge clump of grass with one hand, and it barely has anything holding it to the ground,” Wood said.

Sea level rise can threaten the roots of smooth cordgrass, even as the leafy part of the plant can appear healthy. The exposed roots of smooth cordgrass are seen here at a marsh edge along the Folly River in Georgia. Credit: Kyle Runion/Colorado State University BERM and Biomass

To understand how Georgia’s marshes are responding to changing conditions, researchers developed and tested the Belowground Ecosystem Resilience Model (BERM) in 2021. BERM draws from satellite and climate data to estimate the belowground biomass of Spartina alterniflora, or smooth cordgrass, in coastal areas.

In the 2021 study, the team collected information on environmental conditions in Georgia salt marshes from Landsat 8, Daymet climate summaries, and other publicly available datasets. They built a machine learning model that could predict belowground biomass and trained it on field data from four marsh sites. Researchers found that elevation, vapor pressure, and flooding frequency and depth were some of the most important variables in predicting root biomass.

How a salt marsh looks on the surface isn’t necessarily an indicator of how it’s truly faring.

In the new study, Runion and his colleagues applied the model to estimate changes in S. alterniflora root biomass over nearly 700 square kilometers of Georgia coast between 2014 and 2023.

During that time, belowground biomass decreased about 1% per year on average, the team found. About 72% of the salt marsh area saw declines in underground plant mass. At the same time, aboveground biomass—the visible part of the marsh grass—increased over most of the study area.

The disparity between biomass above and below could occur because aboveground biomass is less sensitive to flooding than root systems. Or the increase might be temporary, as flooding initially delivers nutrients but eventually drowns the plant. In either case, how a salt marsh looks on the surface isn’t necessarily an indicator of how it’s truly faring.

Tool for Conservation

Early-warning signs of marsh decline provided by the model could be crucial for conservation. “Once [marsh] loss occurs, that can be irreversible,” Runion said. “By getting a sign of deterioration before loss happens, that’s when we can intervene and much more easily do something about this.”

Mapping which areas of the marsh are most vulnerable could also combat the tendency to see marshes as either “doomed” or “not doomed” and target conservation efforts to the areas most in need, said Denise Reed, a coastal geomorphologist at the University of New Orleans who was not involved in the study. Though belowground biomass is declining on average, some areas of the coast are experiencing less change than others.

“There are some complex patterns going on—probably something that it would be great to understand a little bit better,” Reed said. But “this idea of being able to detect areas which are in worse condition versus areas that are in better condition from the soil’s perspective is really helpful.”

For now, BERM can predict belowground biomass only in Georgia marshes. Other regions have different plant species and flooding dynamics that could alter the relationships BERM relies on. But with additional calibration data from other salt marshes, the team could make the model more widely applicable, Runion said.

“We are looking to expand this sort of modeling framework to include different species along the Gulf and East Coast,” Runion said.

—Skyler Ware (@skylerdware), Science Writer

Citation: Ware, S. (2025), Machine learning model flags early, invisible signs of marsh decline, Eos, 106, https://doi.org/10.1029/2025EO250253. Published on 17 July 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.

Hot spot generation in hybrid $X$ pinches on a portable low-inductive KING generator

Physical Review E (Plasma physics) - Thu, 07/17/2025 - 10:00

Author(s): T. A. Shelkovenko, I. N. Tilikin, A. R. Mingaleev, V. M. Romanova, and S. A. Pikuz

The small-sized, low-voltage, and low-inductive KING generator (190–230 kA, 40 kV, 200–240 ns) was specially designed to work with X-pinches; however, it was unstable in its original design. In the present work, it is experimentally shown that an increase in the inductance of the output node of the …


[Phys. Rev. E 112, 015207] Published Thu Jul 17, 2025

Clear-cutting forests linked to 18-fold increase in frequency and size of floods

Phys.org: Earth science - Thu, 07/17/2025 - 09:05
Clear-cutting can make catastrophic floods 18 times more frequent with effects lasting more than 40 years, according to a new UBC study.

New study shows hurricane hunter flights significantly increase forecast accuracy

Phys.org: Earth science - Wed, 07/16/2025 - 19:20
When a hurricane is in the forecast, the National Oceanic and Atmospheric Administration (NOAA) deploys its famed Hurricane Hunter team to gather data directly from the storm. The team uses specialized aircraft to fly into the hurricane and collect information about its intensity, structure, and movement, which is used to improve forecasts and warnings.

MethaneSat: The climate spy satellite that went quiet

Phys.org: Earth science - Wed, 07/16/2025 - 18:20
Satellites circling Earth have many different functions, including navigation, communications and Earth observation. About 8%–10% of all active satellites are military or "dual use" serving intelligence or reconnaissance functions as spy satellites.

Tiny crystals hold the key to Augustine Volcano's dramatic 2006 eruption

Phys.org: Earth science - Wed, 07/16/2025 - 17:06
Samples of extremely small crystal clots, each polished to the thickness of a human hair or thinner, have revealed information about the process triggering the major 2006 eruption of Alaska's Augustine Volcano.

A transatlantic communications cable does double duty

Phys.org: Earth science - Wed, 07/16/2025 - 16:00
Monitoring changes in water temperature and pressure at the seafloor can improve understanding of ocean circulation, climate, and natural hazards such as tsunamis. In recent years, scientists have begun gathering submarine measurements via an existing infrastructure network that spans millions of kilometers around the planet: the undersea fiber-optic telecommunications cables that provide us with amenities like Internet and phone service.

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