Contrasting catastrophic eruptions predicted by different intrusion and collapse scenarios

Area of Science:

• Geosciences
• Volcanology
• Geophysics

Background:

• Catastrophic volcanic eruptions can be triggered by landslide collapses, leading to either vertical or lateral (sideways) explosive events.
• Magma intrusion dynamics are linked to both eruption styles, but the specific mechanisms and predictive precursors remain unclear.

Purpose of the Study:

• To investigate the physical processes governing landslide-triggered volcanic eruptions.
• To identify precursors for forecasting vertical versus lateral eruption scenarios.

Main Methods:

• Physical analogue modeling of volcanic systems.
• X-ray Multiple Detector Computed Tomography (X-ray MDCT) scanning to visualize internal magma intrusion, faulting, and surface deformation evolution.

Main Results:

• Identified three distinct volcano deformation patterns resulting from magma intrusions.
• Discovered an early-developing listric slump fault, creating asymmetric intrusion and deformation, which unifies explanations for lateral and vertical eruption scenarios.
• Determined that lateral blasts occur when intrusions reach the sliding block during flank collapse; otherwise, vertical expansion is favored by summit dilatation and flank buttressing.

Conclusions:

• The early deep potential slip surface provides a unified mechanism for landslide-triggered vertical and lateral volcanic eruptions.
• Distinctive surface deformation patterns, particularly early oblique development relative to major faults, can potentially forecast laterally directed blast events.