Flow-dominated eruptions .28Promethean Volcanism.29 Volcanology of Io

culann patera, example of flow-dominated eruption

flow-dominated eruptions long-lived events build extensive, compound lava flows. extent of these flows makes them major terrain type on io. in style of eruption, magma emerges onto surface vents on floor of paterae, vents surrounding paterae, or fissures on plains, producing inflated, compound lava flows similar seen @ kīlauea in hawaii. images galileo spacecraft revealed many of io s major flows, @ prometheus , amirani, produced build-up of small breakouts of lava on top of older flows. flow-dominated eruptions differ explosion-dominated eruptions longevity , lower energy output per unit of time. lava erupts @ steady rate, , flow-dominated eruptions can last years or decades.

active flow fields more 300 kilometres (190 mi) long have been observed on io @ amirani , masubi. relatively inactive flow field named lei-kung fluctus covers more 125,000 square kilometres (48,000 sq mi), area larger nicaragua. thickness of flow fields not determined galileo, individual breakouts on surface 1 m (3 ft) thick. in many cases, active lava breakouts flow out onto surface @ locations tens hundreds of kilometres source vent, low amounts of thermal emission observed between , breakout. suggests lava flows through lava tubes source vent breakout.

although these eruptions have steady eruption rate, larger outbreaks of lava have been observed @ many flow-dominated eruption sites. example, leading edge of prometheus flow field moved 75 95 kilometres (47 59 mi) between observations voyager in 1979 , galileo in 1996. although dwarfed explosion-dominated eruptions, average flow rate @ these compound flow fields greater observed @ similar contemporary lava flows on earth. average surface coverage rates of 35–60 square metres (380–650 sq ft) per second observed @ prometheus , amirani during galileo mission, compared 0.6 square metres (6.5 sq ft) per second @ kīlauea.