There are hundreds of active volcanoes located around the world. Not every volcano erupts with the same characteristics, however. For this reason, scientists have been using a classification scheme that names the type of eruption that any given volcano displays. This classification provides a description of how large the eruption is and what its potential impacts are.
The Types of Magmatic Eruptions
The names given to a type of volcanic eruption caused by magmatic activity are taken from famous volcanoes that display that style of eruption. These types are:
- Hawaiian (VEI 0 - 1)
- Strombolian (VEI 1 - 2)
- Vulcanian (VEI 2 - 3)
- Pelean (VEI 3 - 4)
- Plinian and Ultra-Plinian (VEI 4 - 8)
Hawaiian eruptions are characterized as low energy eruptions - also called effusive eruptions - of basaltic lava and gases, much like the current eruption of Kilauea Volcano, Hawaii. These eruptions typically emit ash and gas plumes that are no higher than 1 km and are considered non-explosive eruptions. There are many volcanoes around the world that display Hawaiian eruptions almost daily.
Strombolian eruptions are more explosive than Hawaiian eruptions, but these eruptions are still considered mild. Similar to the type of eruption exhibited by the island volcano Mt. Stromboli in Italy, Strombolian eruptions emit low-level blasts of basaltic and andestic lava a few kilometers above the vent, with most material falling out near the vent.
Vulcanian eruptions are explosive and eject viscous silica magma, such as andesite and rhyolite magma, up to 10 km above the vent. The ash columns produced by these eruptions can fall and create pyroclastic flows that can be very hazardous to communities living near the volcano. Vulcanian eruptions are named for Vulcano, one of the island volcanoes north of Sicily.
Pelean eruptions are severe and create hazardous pyroclastic flows that are a result of collapsing andesitic or rhyolitic lava domes or collapsing ash columns that can go as high as 15 km above the vent. Pelean eruptions are named for Mt. Pelee which erupted deadly pyroclastic flows in 1902 that destroyed the town of Saint-Pierre on the island of Martinique. In 1997, Soufriere Hills on the island of Montserrat exhibited a Pelean type eruption, which produced a pyroclastic flow that traveled 4.5 km away from the volcano and killed about two dozen people.
Plinian eruptions are characterized as a colossal explosion that can generate ash and gas columns from 11 km to more than 25 km into the atmosphere (Ultra-Plinian). Plinian eruptions are named for Pliny the Younger, whose written descriptions of the eruption of Mt. Vesuvious in 79 A.D. describe an event that was cataclysmic and deadly. More recent Plinian eruptions include the 1991 eruption of Mt. Pinatubo in the Philippines, which produced an eruption column that sent ash and gas 35 km into the atmosphere. Plinian eruptions, like that of Mt. Pinatubo in 1991, have been known to affect the global climate for years after the eruption due to the high amount of particles and gases injected into the atmosphere. Plinian eruptions are also referred to as Vesuvian eruptions.
Phreatomagmatic and Phreatic Eruptions
Non-magmatic type eruptions are called phreatomagmatic and phreatic eruptions. Phreatomagmatic eruptions occur when ground water and magma are combined underground. The result is a steam explosion that includes lava rock fragments and bombs. Phreatic eruptions are also caused by ground water coming into contact with magma and causing a steam explosion. In this case, though, no new magma material is ejected, although pre-existing rock fragments may erupt with the steam explosion.
Related Articles
The Five Deadliest Volcanic Eruptions
Sources
USGS Volcano Hazards Program - Photo Glossary of Volcanic Terms
Smithosonian Institution's Global Volcanism Program
 |
 |
 |
 |
 |
