Volcanic lightning
Lightning produced by a volcanic eruption / From Wikipedia, the free encyclopedia
Volcanic lightning is an electrical discharge caused by a volcanic eruption rather than from an ordinary thunderstorm. Volcanic lightning arises from colliding, fragmenting particles of volcanic ash (and sometimes ice),[1][2] which generate static electricity within the volcanic plume,[3] leading to the name dirty thunderstorm.[4][5] Moist convection currents and ice formation also drive the eruption plume dynamics[6][7] and can trigger volcanic lightning.[8][9] Unlike ordinary thunderstorms, volcanic lightning can also occur when there are no ice crystals in the ash cloud.[10][11]
The earliest recorded observations of volcanic lightning[12] are from Pliny the Younger, describing the eruption of Mount Vesuvius in 79 AD, "There was a most intense darkness rendered more appalling by the fitful gleam of torches at intervals obscured by the transient blaze of lightning."[13] The first studies of volcanic lightning were also conducted at Mount Vesuvius by Luigi Palmieri[14] who observed the eruptions of 1858, 1861, 1868, and 1872 from the Vesuvius Observatory. These eruptions often included lightning activity.[13]
Instances have been reported above Alaska's Mount Augustine volcano,[15] Iceland's Eyjafjallajökull and Grimsvotn,[16] Mount Etna in Sicily, Italy,[17] Taal Volcano in the Philippines,[18][19] and Mount Ruang in Indonesia.[20]