Magma fragmentation by rapid decompression

摘要: THE processes leading to magma fragmentation and the generation of pyroclastic debris during explosive volcanic eruptions are fundamental importance in volcanology. Observations eruptions1–3, as well theoretical analyses underlying processes4, have raised question whether rapid decompression highly viscous, vesicular that results from collapse a lava dome or edifice can, itself, produce pyroclast formation. Here we report laboratory investigation formation following decompression. Samples 1980 eruption Mount St Helens, when rapidly depressurized initial pressures up 12 MPa (and at temperatures range 750–825 °C), fragmented form products many respects similar those formed real eruptions. Moreover, observe below normally associated with magmatic processes, suggesting even relatively cool bodies can be very hazardous subjected unloading events.