Phys.org: Earth science

A new study finds that commercial satellite imagery data often outperforms public data sets when identifying surface water, but that public data sets may be better at detecting water hidden by forest cover. Satellite imagery is a powerful tool for mapping surface water, from the movement of rivers and streams to water levels and even water temperatures. The effectiveness of those satellites depends on their ability to identify water in the images they capture.

Understanding what triggers large volcanic eruptions is crucial for hazard assessment, but the exact mechanism driving these eruptions is still poorly understood. The prevailing theory is that volatile exsolution—gas coming out of magma—is a main driver of eruptions, particularly in volcanoes rich in silica. However, a new study, published in Nature Communications, posits that it is actually gas being dissolved back into the magma that leads to the pressurization needed for large eruptions.

Severe Tropical Cyclone Narelle continues to amaze us with its long journey across northern Australia. This cyclone began life near the Solomon Islands on March 16, when moist air rose rapidly and created a low-pressure zone.

Although volcanic eruptions are spectacular natural events that occur around the world every day, most volcanoes spend the majority of their time not erupting. To accurately forecast volcanic activity, it's important to characterize the magma before an eruption is imminent.

The magma reservoir of the largest volcanic eruption of the Holocene is refilling. This Kobe University insight on the Kikai caldera in Japan allows us to understand giant caldera volcanoes like Yellowstone or Toba more generally and gets us closer to predicting their behavior, too.

New research from a team at Trinity College Dublin has unearthed a cheap and environmentally friendly new option for removing pollutants from our water. The key? Oyster shells that would ordinarily end up in landfill sites after consumption. The research, just published in the journal Science of the Total Environment, shows that waste seashells—especially those from oysters—can capture and remove rare earth elements from polluted water. And what's more, they do it entirely naturally, turning them into stable mineral crystals.

The Phlegraean Fields volcanic complex, located beneath the metropolitan area of Naples—a city of 900,000 inhabitants in Italy—has been rising increasingly since 2005, accompanied by a growing number of small earthquakes. This development has been attracting increasing attention in the densely populated region for years. Although such phases of uplift and subsidence have occurred there for over a thousand years, the relationship between ground uplift and seismic activity is complex and not yet fully understood.

The structure of the plant communities that grow on the thawing permafrost in the Arctic is changing, with grasses displacing slower-growing shrubs. Although these grasses bind more carbon dioxide than previous plant communities, they lead to far more methane emissions over the course of the year. Methane is a greenhouse gas that accelerates the global temperature rise much faster than carbon dioxide.

For the second consecutive year, winter sea ice in the Arctic reached a level that matches the lowest peak observed since satellite monitoring began in 1979. On March 15, Arctic sea ice extent reached 5.52 million square miles (14.29 million square kilometers), very close to the 2025 peak of 5.53 million square miles (14.31 million square kilometers). Scientists with NASA and the National Snow and Ice Data Center (NSIDC) at the University of Colorado, Boulder, note that the two years are statistically tied.

Improving tsunami hazard assessments depends on understanding what happens at the moment an earthquake ruptures beneath the seafloor, especially near deep-ocean trenches where measurements are often scarce. When a powerful magnitude 8.8 earthquake struck off Russia's Kamchatka Peninsula on July 29, 2025, it generated a tsunami that traveled across the Pacific.

The analysis of a sediment core from an oasis lake in Chad provides new insights into the history of precipitation in the Sahara. The study, led by the University of Cologne, shows that a prolonged wet phase, which lasted from 14,800 to 5,500 years ago, was interrupted by short-term droughts. Such drought events could also occur in a similar manner in the future.

The tropical Pacific Ocean and the frozen expanse of Antarctica sit more than 10,000 kilometers apart. Yet new research shows that when surface waters warm near the equator in northern winter, the Antarctic stratosphere responds months later—a delayed reaction that could improve predictions of Southern Hemisphere climate patterns.

Earthquakes occur when the tectonic plates of the Earth's crust shift, jolting past each other in a release of built-up tension. However, other natural forces can also influence seismic activity: Hydrological dynamics, like changes in groundwater and snowpacks, in particular, put pressure on faults. A new study from Caltech finds that a higher rate of change in groundwater levels leads to a noticeable increase in seismic activity. The work is published in the journal Science Advances.

A wildfire forecasting system powered by artificial intelligence (AI) could help detect dangerous fire conditions earlier and reduce the cost of wildfire response, according to new research from Te Whare Wānanga o Waitaha, University of Canterbury (UC). The work is published in the International Journal of Wildland Fire.

This past winter, the Rocky Mountains experienced an historic snow drought, a worrying development for the tens of millions of people in the arid American West who depend on snowmelt for water. Now, a new study in the journal Geology investigates the geologic history of a surprising process that might be making the problem even worse: sublimation, the process by which frozen water transforms directly into water vapor, skipping the liquid phase altogether.

Across much of the Western United States, winter 2026 was the year the snow never came. Many ski resorts got by with snowmaking but shut down their winter operations early. Fire officials and water supply managers are worried about summer.

Earth's magnetic field acts as a vital shield against radiation arriving from space, but it is not constant. A new international study has examined how a reduction of the magnetic field similar to the Laschamps excursion would affect aviation on routes such as Helsinki–Dubai and Helsinki–New York if it occurred today.

Researchers have used artificial intelligence to develop a new tool for assessing earthquake damage, a leap that could ultimately help first responders in making critical rescue decisions, suggests a new study. The team's AI, called the LoRA-Enhanced Ground-view Generation (LEGG) diffusion model, is trained on real aerial drone images that it uses to create highly photorealistic 3D reconstructions of the ground. Creating imagery detailed enough to fully capture a region's physical characteristics distinguishes this synthetic model, enabling it to recognize complex visual patterns and predict where structures may be damaged, even in densely populated urban areas.

Fires are a recurring phenomenon in central South America, often intensified by drought and deforestation. In 2024, wildfire activity reached its highest levels in 20 years, affecting vast areas of the Amazon rainforest and the Cerrado—the world's most biodiverse tropical savanna, stretching across one-fifth of Brazil and extending into Bolivia and Paraguay.

Rising sea surface temperatures in coastal waters are driving 50 to 64 percent of the increase in large-scale humid heat waves, according to new research. The study, from researchers at the Potsdam Institute for Climate Impact Research (PIK), Princeton University and Sun Yat-sen University, implies that coastal sea surface temperatures could be a potential early warning indicator for widespread humid heat extremes. The paper is published in the journal Nature Geoscience.