7 terms

Pyroclastic Flows

What is a Pyroclastic flow?
Ground hugging composite if ash, magmatic gases and rock. Hot and dry. Follows topograpy
What is a Pyroclastic blast?
Laterally directed blasts that travel far but are short lived
What is a PDC?
Pyroclastic density currents exert abnormally high pressure eon obstacles causing structural damage and collapse
Triggers of Pyroclastic flows?
Plininan eruption column collapse (Mt Pinatubo) Volcanic Vents (Mt St Helens) lava dome collapse (Soufriere Hills)
Dangers of PC Flows?
Asphyxiation, burial, incineration. Almost impossible to predict and avoid
Distance PC Flows travel?
Up to several kilometres. Volcanoes with longer eruptions tend to travel further as the topography is smoother. Depends on the amount of ejected material and the height of collapse if a column or vent is involved
Mitigation of Pyroclastic flows?
Difficult pre - evacuation is the only way and hazard maps which are based off of previous flow pathways and topograpy