Precursor-free eruption triggered by edifice rupture at Nyiragongo volcano

Area of Science:

• Volcanology
• Geophysics
• Geochemistry

Background:

• Classical volcanic eruption models involve pressure buildup and magma ascent.
• Open-vent volcanoes with persistent lava lakes present unique monitoring challenges.
• The 2021 Mount Nyiragongo eruption deviated from typical precursor-driven models.

Purpose of the Study:

• To investigate the atypical flank eruption of Mount Nyiragongo on May 22, 2021.
• To analyze the reversed sequence of eruption precursors and magma movement.
• To understand the mechanisms behind edifice rupture and subsequent dyke intrusion.

Main Methods:

• Analysis of geophysical and geochemical data.
• Modeling of magma ascent and dyke propagation.
• Interpretation of the Mount Nyiragongo 2021 flank eruption sequence.

Main Results:

• The Mount Nyiragongo eruption was initiated by edifice rupture, not typical magma ascent.
• A 25-km-long dyke intruded shallowly beneath Goma, Gisenyi, and Lake Kivu.
• The eruption occurred without apparent precursors, with magma motion following the eruption.

Conclusions:

• The study challenges conventional eruption precursor models for open-vent volcanoes.
• The findings highlight risks of hazardous events like urban effusions or limnic eruptions.
• Effective monitoring and risk management for shallow magma systems remain critical.