Latest Volcanic Ash Advisory Center Stories
Thousands of planes are grounded across Europe due to the spread of volcanic ash following the recent eruption under Iceland's Eyjafjallajoekull glacier.
New Scripps study of low-frequency sound from Mount St. Helens and Tungurahua volcanoes provides explanation for how the large-amplitude signals from eruptions are produced.
Volcanic ash is the term for very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. Ash is created when solid rock shatters and magma separates into minute particles during explosive volcanic activity. The usually violent nature of an eruption involving steam (phreatic eruption) results in the magma and perhaps solid rock surrounding the vent, being torn into particles of silt to sand size. The plume that is often seen above an erupting volcano...