A multidisciplinary team of experts, consisting of geoscientists, meteorologists, geologists and volcanologists, has proposed an innovative theory to understand the nature of lava fountains. Their study was published in Nature Communicationsfocus on the volcanic eruption in 2021 Fagradalsfyal In Iceland, which has produced amazing examples of this phenomenon.
Contrary to the common perception of volcanic eruptions as violent explosions, lava fountains appear as continuous jets of magma shooting upward. The reasons for this amazing display of energy remain unclear, with some hypotheses pointing to rapid movement of magma towards the surface. In their innovative approach, the researchers carefully examined the Vagradalsfjall eruption, which is characterized by jets of different heights and a non-explosive pattern.
Unlike conventional eruptions, the Vagradalsfjall eruption did not occur in a single explosive episode, but manifested itself as a series of jets. This allowed researchers to get closer and study the phenomenon more closely. Using an advanced infrared spectroscopy instrument, they analyzed the gases released during four cycles of eruption and pause.
the theory
Credit: Nature Communications (2023)
Study of the chemical composition of gases revealed crucial properties to explain the formation of volcanic fountains. The new theory suggests that volcanoes like Fagradalsfjall have a shallow cavity beneath the caldera, filled with magma. When lava flows into the cavity, gases cause a layer of foam to form at the top. The periodic collapse of this layer of foam generates pressure, pushing the magma into the air and creating a fountain effect, similar to opening a can of soda. The periodic nature of the fountain is attributed to the repeated formation of the foam layer within the cavity.
While more research is needed to confirm this theory, the team suggests it could help explain volcanic geysers in different parts of the world.
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