Strain-induced magma fragmentation in explosive eruptions.

Area of Science:

• Volcanology
• Geophysics
• Materials Science

Background:

• Explosive volcanic eruptions are driven by magma fragmentation, transforming bubbly magma into gas-pyroclast dispersions.
• The precise mechanisms of magma fragmentation remain poorly understood, hindering accurate volcanic hazard forecasting.
• Current models lack a comprehensive understanding of the transition from effusive to explosive eruption styles.

Purpose of the Study:

• To develop a new model for magma fragmentation during volcanic eruptions.
• To incorporate a fragmentation criterion based on rate-limited glass transition into magma ascent dynamics.
• To reconcile experimental, theoretical, and observational data on explosive volcanic eruptions.

Main Methods:

• Development of a multiphase fluid-dynamic model for magma ascent.
• Incorporation of a novel fragmentation criterion based on the glass transition.
• Numerical simulations of magma ascent and fragmentation processes.

Main Results:

• The model demonstrates the feasibility of strain-induced brittle fragmentation of magma.
• Numerical results align with experimental findings and theoretical predictions.
• The model successfully explains volcanic products from large explosive eruptions.

Conclusions:

• Strain-induced brittle fragmentation is a viable mechanism for explosive volcanic eruptions.
• The developed model provides a unified framework for understanding magma fragmentation.
• This research enhances our ability to forecast volcanic hazards and discriminate eruption styles.