Ashfall, as a substance, consists of unconsolidated pyroclastic material (volcanic ash) deposited from the atmosphere following explosive volcanic eruptions. It is composed predominantly of fine-grained, angular fragments of volcanic glass, crystalline minerals (e.g., plagioclase, pyroxene), and lithic clasts, typically less than 2 mm in diameter. The material exhibits high abrasiveness, variable porosity, and chemical reactivity governed by its silica content and surface coatings of soluble salts. Ashfall deposits influence soil geochemistry, hydrology, and atmospheric processes, and present critical considerations for inhalation toxicology, material corrosion, and mechanical loading on structures in volcanological and environmental research.
On November 23, 2025, the Hayli Gubbi volcano in northern Ethiopia erupted in dramatic fashion. The shield volcano in the Danakil (or Afar) Depression began spewing ash and volcanic gases at around 11:30 a.m. local time (8:30 ...
Environment
Dec 8, 2025
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A research group in Japan has suggested that ash released from volcanic eruptions on Nishinoshima Island—part of Japan's Ogasawara Islands—led to a temporary surge in phytoplankton levels in the seawater around Mukojima Island, ...
Earth Sciences
Oct 2, 2025
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Deep below the surface of the ocean, bacteria and critters that feed off nutrients spouting from hydrothermal vents met with a sudden wave of volcanic sediment, leaving them suffocated.
Earth Sciences
Jul 2, 2025
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Volcanoes inspire awe with spectacular eruptions and incandescent rivers of lava, but often their deadliest hazard is what quietly falls from the sky.
Earth Sciences
Apr 15, 2025
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When the Kīlauea Volcano erupted in May 2018, an enormous amount of ash was released into the atmosphere in a plume nearly five miles high. A new study by an international team of researchers revealed that a rare and large ...
Earth Sciences
Apr 9, 2025
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