Context: A fissure eruption started on the Reykjanes Peninsula. This marks the fourth eruption on the Reykjanes Peninsula in three years.
Iceland Volcanic eruption
- On average, a volcano erupts in Iceland erupts every five years.
- Since 2021, however, the frequency has been closer to every 12 months! The area broadly known as Fagradalsfjall, some 35km from the capital Reykjavík, flared to life after a series of earthquakes on the Reykjanes Peninsula.
- The three eruptions - some consider one single eruption with months-long pauses - mark the beginning of a new geological era on the southwestern peninsula, which has been dormant for the past 800 years.
- Unlike most volcanic eruptions -- occurring on the interior highlands, the lava hidden under ice and/or with lethal volumes of volcanic gases -- Fagradalsfjall was the ideal 'tourist volcano': Small in relative terms and accessible for all levels of fitness.
- The last eruption ended in August 2023, but the site still remains a major attraction. The thick, black crust of lava paves the landscape with crumbling craters and steam.
- Of Iceland’s 32 active volcanoes, none is watched more closely than Katla.
- One of the nation’s largest and most feared, Katla lies under glacial ice hundreds of meters (yards) thick, meaning that any eruption is likely to melt the ice and cause widespread flooding.
Nature and Reason
- The nature of eruptions in Iceland is diverse, from small effusive eruptions where lava flows quietly from fissures and crater rows to significant explosive eruptions in ice-covered central volcanos that produce large ash plumes.
- In Iceland, volcanic vents, which can be long fissures, often open parallel to the rift zones where the Eurasian and the North American lithospheric plates are diverging, a system which is part of the Mid-Atlantic Ridge.
- The reason for Iceland's intense volcanic activity is the country's geological position, where dynamic geological forces are at work between the spreading plate boundary on the Mid-Atlantic Ocean ridge and a powerful mantle plume creating a hot spot on the surface.
- Together, they produce large amounts of magma, filling the gaps in the crust made by the spreading plates, resulting in frequent eruptions along the rift zone.
Fissure eruption: A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and maybe many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes.
Mantle plume: It is a buoyant mass of material in the mantle, which rises because of its buoyancy. The existence of mantle plumes in Earth was first suggested by J. Tuzo Wilson (1963) as an explanation of oceanic island chains, such as the Hawaiian-Emperor chain, which change progressively in age along the chain.
Geysers: Geyser, hot spring that intermittently spouts jets of steam and hot water. The term is derived from the Icelandic word geyser, meaning “to gush.” Geysers result from the heating of groundwater by shallow bodies of magma. They are generally associated with areas that have seen past volcanic activity.
Fumaroles are vents or openings at the surface where volcanic gases and vapors are emitted. Fumaroles are common features on active volcanoes and are an important sign that a volcano is active in that fumaroles indicate the presence of heat from volcanic sources.
