Phreatic eruption at the summit of Mount St. Helens, Washington. Hundreds of these steam-driven explosive eruptions occurred as magma steadily rose into the cone and boiled groundwater. These phreatic eruptions preceded the volcano's plinian eruption on 18 May 1980

Immagini allegate
30210599-012_large.jpg (87.76 KB, 21 download)
michele conti
fatti non foste per viver come bruti ma per seguir virtute e conoscenza