2023-12-24 05:00:00
Eruption on the island of Anak Krakatau, Indonesia, in 2018. Photo: Reproduction. Tiago Robles Meteored Brazil 24/12/2023 06:00 5 min
In this study, recently published in the journal Contributions to Mineralogy and Petrology, researchers analyzed the eruptive history of the Ciomadul volcano, located in Romania, and discovered that even dormant volcanoes hide an explosive surprise inside and can awaken with great force after thousands of years of inactivity.
Analysis of the eruptive activity of the Ciomadul volcano
Ciomadul is one of the youngest volcanoes in Central and Eastern Europe and has not erupted for around 30,000 years.
Researchers studied Ciomadul’s cycle of volcanic activity over the last millennium in order to determine the types of past eruptions and the ages of the rocks, to better understand its eruptive patterns and the transitions from effusive (softer, with a constant flow of lava) to explosive (sudden release of gas and lava) eruptions under intense pressure).
Effusive eruptions have relatively smooth lava flow, while explosive eruptions are characterized by intense internal pressure and the presence of gases that lead to powerful eruptions, with considerable release of ash and rock.
To do this, they carried out a detailed analysis of the crystals and minerals present in the volcanic rocks of Ciomadul. The chemical composition and water content of these rocks provide clues to the eruption conditions that formed them and when they formed. The team focused on the volcano’s most recent explosive eruption period – from about 56,000 years ago to 30,000 years ago.
Results on the volcano magma
Two magmatic zones were discovered: an upper zone, 8 to 12 kilometers deep, and a lower zone, 16 to 40 kilometers deep. And the way magma rises to the surface appears to depend on its origin : If it is composed mainly of molten lithosphere, the chemicals allow a slow release, but if oceanic plates enter the mixture, the chemical release becomes more explosive.
Moreover, crystallinity and increased water content of magma played an important role in the transition from effusive to explosive eruptions after an interval of about 10,000 years or more.
Sfânta Ana lake located in the crater of the Ciomadul volcano, Romania. Credit: Kosa István.
“The most recent eruptions were formed by more dangerous explosive eruptions than the previous active episode,” said Barbara Cserép, lead author of the study.
“There have been several long periods of dormancy over the life of the volcano, which spans nearly a million years, but even after tens of thousands of years, sometimes even after more than 100,000 years of inactivity, volcanic eruptions have resumed“said Szabolcs Harangi, co-author of the study.
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In summary, the analyzes therefore indicate that long-dormant volcanoes can erupt with great explosive power after long periods of inactivity.
The importance of research
According to the authors, Volcanic eruptions – whatever their magnitude – represent a significant, often underestimated, risk to modern society.
In this way, the research can help detect signs of an impending eruption, providing predictive models of future volcanic behavior. It also serves as a reminder of the potential risks associated with potentially active volcanoes and the need for continuous monitoring and early detection systems for public safety.
References :
CSERÉP, B. et al. Constraints on the pre-eruptive magma storage conditions and magma evolution of the 56–30 ka explosive volcanism of Ciomadul (East Carpathians, Romania). Contributions to Mineralogy and Petrologyv. 178, 2023.
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