Related topics: volcano

Iceland eruption confirms faultline has reawakened: Expert

A volcanic eruption that has engulfed homes in an Icelandic fishing port confirms that a long-dormant faultline running under the country has woken up, threatening to belch out lava with little warning for years to come, ...

Tonga volcano unleashed fastest ever undersea flows: study

An unprecedentedly violent volcanic eruption that triggered a tsunami off the Pacific island nation of Tonga in 2022 unleashed the fastest underwater currents ever recorded, according to a study published on Thursday.

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Volcanic ash

Volcanic ash consists of small tephra, which are bits of pulverized rock and glass created by volcanic eruptions, less than 2 millimetres (0.079 in) in diameter. There are three mechanisms of volcanic ash formation: gas release under decompression causing magmatic eruptions; thermal contraction from chilling on contact with water causing phreatomagmatic eruptions and ejection of entrained particles during steam eruptions causing phreatic eruptions. The violent nature of volcanic eruptions involving steam results in the magma and solid rock surrounding the vent being torn into particles of clay to sand size. Volcanic ash can lead to breathing problems, malfunctions in machinery, and from more severe eruptions, years of global cooling.

Ash deposited on the ground after an eruption is known as ashfall deposit. Significant accumulations of ashfall can lead to the immediate destruction of most of the local ecosystem, as well the collapse of roofs on man-made structures. Over time, ashfall can lead to the creation of fertile soils. Ashfall can also become cemented together to form a solid rock called tuff. Over geologic time, the ejection of large quantities of ash can produce an ash cone.

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