Potassium Levels Identified as Key Indicator for Large volcanic Eruptions and Caldera Formation
YOGYAKARTA, Indonesia – A groundbreaking study from Universitas Gadjah Mada (UGM) has revealed that potassium levels in volcanic rock are a more reliable indicator of eruption potential, particularly for large-scale events that form calderas, than previously used metrics like silica and magnesium. This revelation offers a important advancement in volcanic monitoring and disaster mitigation strategies.
While silica and magnesium levels often overlap across different volcano types, making them arduous to use for differentiation, the UGM research highlights a distinct difference in potassium content. Caldera-type volcanoes, including prominent examples in Indonesia such as Raung, Ijen, Bromo, and Dieng, exhibit substantially higher potassium concentrations compared to stratovolcanoes and compound volcanoes.
Previous research has suggested that higher potassium content in magma allows it to hold more dissolved gases under pressure. When this magma undergoes rapid decompression, the sudden release of these gases can fuel large, explosive eruptions, leading to the collapse of a volcanic peak and the formation of a caldera.
Beyond geochemical analysis, the study also emphasizes the role of tectonic factors. The research indicates that a steeper subduction plate angle beneath East Java,compared to Central and West Java,contributes to the formation of potassium-rich magma. This geological condition is reflected in the higher prevalence of caldera formations in East Java, with examples like ijen Caldera, Raung, Jambangan, and Bromo situated in areas where the subduction zone is deeper. In contrast, areas with shallower subduction, such as Central Java (Dieng Caldera) and West Java (Swamp lake and Sunda Caldera), show fewer caldera formations.
Based on these findings, the UGM research team has proposed three distinct evolutionary pathways for volcanoes:
- Stratovolcano to Caldera: This pathway describes the transformation of a stratovolcano into a caldera without passing through a compound phase, driven by a substantial increase in potassium levels.
- Stratovolcano to Compound to Caldera: In this scenario,a volcano first develops into a compound type before eventually forming a caldera,a process also characterized by the magma’s evolution towards high potassium content.
- Stratovolcano to Compound only: This path represents volcanoes that evolve into compound types but are unlikely to form calderas due to persistently low potassium levels.
The implications of this research are far-reaching for disaster management. Traditionally, the potential for large eruptions has been assessed based on silica content or the physical size of a volcano. However,this study establishes potassium as a crucial new parameter for early warning systems. By monitoring potassium levels, authorities can gain a more accurate understanding of a volcano’s potential for large eruptions that coudl lead to caldera formation, thereby enhancing preparedness and mitigation efforts.
