Strombolian eruptions are characterized by the ejection of material tens or hundreds of feet in the air. When lava flows are present, they are shorter and thicker than that of Hawaiian eruptions. Vulcanian eruptions usually begin with steam explosions which remove old layers of rock from the vent. An eruption cloud of ash forms and is commonly accompanied by lightening within the cloud. Lava flows are thick and viscous.
Peleean eruptions begin with the formation of domes and avalanches of glowing lava.
Later, magma forms a steep-sided dome or outcropping within the vent which can then collapse resulting in additional ash flows. Plinian eruptions are named for the Roman naturalist, Pliny the Elder, who died during an eruption of Vesuvius in AD 79. Many of these eruptions last a few weeks to a few months and the longer of these include showers of ash and lava avalanches. Rhyolitic flood eruptions produce large volumes of material spread over large distances producing broad, nearly level plains. Ultravulcanian eruptions eject solid rock and steam ranging from ash to block-sized material.