Rheological evolution of a trachybasalt from Mt. Etna under slow cooling

Area of Science:

• Geosciences
• Volcanology
• Rheology

Background:

• Magma rheology dictates lava flow behavior and volcanic hazard potential.
• Crystallization significantly influences the rheology of basaltic magmas.
• Limited experimental data exists for magma rheology under slow cooling rates relevant to lava emplacement.

Purpose of the Study:

• To provide new rheological data for magma under slow cooling conditions.
• To investigate the influence of cooling and shear rates on magma crystallization kinetics.
• To offer constraints for numerical modeling of lava flows.

Main Methods:

• Rheological experiments on Etnean trachybasalt at low cooling rates (0.1 and 0.5 °C/min).
• Variable shear strain rates (1-10 s⁻¹) were applied.
• Technical validation included instrument calibration and sample integrity verification.

Main Results:

• Cooling rate is the primary control on crystallization kinetics; shear rate is secondary.
• Observed non-linear dependence of crystallization onset temperature, approaching the liquidus at slower cooling rates.
• Dataset captures rheological evolution relevant to lava flow emplacement.

Conclusions:

• The study provides critical data for understanding magma rheology under quasi-equilibrium conditions.
• Findings enhance the parameterization of lava flow emplacement models.
• This research improves volcanic hazard assessment by detailing lava flow dynamics.