Katana VentraIP

Types of volcanic eruptions

Several types of volcanic eruptions—during which material is expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.

"Eruption" redirects here. For other uses, see Eruption (disambiguation).

There are three main types of volcanic eruption:


Within these broad eruptive types are several subtypes. The weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions; the strongest eruptions are called Ultra-Plinian. Subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength. An important measure of eruptive strength is the Volcanic Explosivity Index an order-of-magnitude scale, ranging from 0 to 8, that often correlates to eruptive types

Gas release under decompression, causing magmatic eruptions

Ejection of entrained particles during steam eruptions, causing phreatic eruptions

Thermal contraction from chilling on contact with water, causing phreatomagmatic eruptions

Puʻu ʻŌʻō, a cinder cone located on Kilauea on the island of Hawaiʻi which erupted continuously from 1983 to 2018. The eruptions began with a 6 km (4 mi)-long fissure-based "curtain of fire" on 3 January 1983. These gave way to centralized eruptions on the site of Kilauea's east rift, eventually building up the cone.[4]

parasitic

For a list of all of the volcanoes of , see List of volcanoes in the Hawaiian – Emperor seamount chain.

Hawaii

Italy.[4]

Mount Etna

in 1986 (see above paragraph)[4]

Mount Mihara

Iceland. The volcano built itself up from depth and emerged above the Atlantic Ocean off the coast of Iceland in 1963. Initial hydrovolcanics were highly explosive, but as the volcano grew, rising lava interacted less with water and more with air, until finally Surtseyan activity waned and became more Strombolian.[50]

Surtsey

in Alaska, 1977, and Capelinhos in the Azores, 1957, both examples of above-water Surtseyan activity.[50]

Ukinrek maars

in New Zealand erupted along a rift zone in 1886, killing 150 people.[50]

Mount Tarawera

a seamount in the Mediterranean Sea, breached sea level in July 1831 and caused a sovereignty dispute between Italy, France, and Great Britain. The volcano did not build tuff cones strong enough to withstand erosion and soon disappeared back below the waves.[52]

Ferdinandea

The Hunga Tonga in Tonga breached sea level in 2009. Both of its vents exhibited Surtseyan activity for much of the time. It was also the site of an earlier eruption in May 1988.[53]

underwater volcano

which exhibited phreatic activity just prior to its catastrophic 1980 eruption (which was itself Plinian).[64]

Mount St. Helens

Philippines, 1965[65] 2020[67]

Taal Volcano

of Guadeloupe (Lesser Antilles), 1975–1976 activity.[65]

La Soufrière

volcano on Montserrat, West Indies, 1995–2012.

Soufrière Hills

has frequent geyser like phreatic eruptions from its crater lake.

Poás Volcano

well known for its sudden phreatic eruptions.

Mount Bulusan

all historical eruptions of this volcano have been phreatic including the deadly 2014 eruption.

Mount Ontake

Indonesia, produces almost annual phreatic eruptions.[68][69]

Mount Kerinci

Phreatic eruptions (or steam-blast eruptions) are a type of eruption driven by the expansion of steam. When cold ground or surface water come into contact with hot rock or magma it superheats and explodes, fracturing the surrounding rock[63] and thrusting out a mixture of steam, water, ash, volcanic bombs, and volcanic blocks.[64] The distinguishing feature of phreatic explosions is that they only blast out fragments of pre-existing solid rock from the volcanic conduit; no new magma is erupted.[65] Because they are driven by the cracking of rock strata under pressure, phreatic activity does not always result in an eruption; if the rock face is strong enough to withstand the explosive force, outright eruptions may not occur, although cracks in the rock will probably develop and weaken it, furthering future eruptions.[63]


Often a precursor of future volcanic activity,[66] phreatic eruptions are generally weak, although there have been exceptions.[65] Some phreatic events may be triggered by earthquake activity, another volcanic precursor, and they may also travel along dike lines.[63] Phreatic eruptions form base surges, lahars, avalanches, and volcanic block "rain." They may also release deadly toxic gas able to suffocate anyone in range of the eruption.[66]


Volcanoes known to exhibit phreatic activity include:

List of volcanic eruptions in the 21st century

List of Quaternary volcanic eruptions

 – Research to predict volcanic activity

Prediction of volcanic activity

Timeline of volcanism on Earth

at Wikimedia Commons (Videos)

Category:Volcanic eruptions

. USGS.

USGS Hawaiian Volcano Observatory (HVO) homepage

.

Distinguishing eruptive types

. San Diego State University.

How Volcanoes Work

Live-Stream: Earth's Volcanoes and Eruptions