Volcanic Eruption Mechanisms, Styles, and Hazards

All flashcards

Phreatomagmatic eruption

An eruption in which direct interaction between magma and water fragments magma and can generate explosive activity.

Hawaiian eruption

Typically effusive activity involving fluid, low-gas basaltic lava that can form fountains and broad shield volcanoes.

Strombolian eruption

Episodic explosions caused by gas slugs bursting through magma and ejecting volcanic fragments.

Vulcanian eruption

A short-lived explosion caused by pressure building beneath a cap of viscous magma or solid material.

Phreatic eruption

A steam-driven blast that ejects pre-existing rock and typically does not bring fresh magma to the surface.

Quiz questions

1. Which feature is most characteristic of typical Hawaiian activity?Answer: Fluid basaltic lava commonly produces fountains and sustained flows.
2. How does a Vulcanian eruption typically begin?Answer: Pressure builds beneath a cap until the cap breaks in an explosion.
3. What hazard is especially associated with collapse of a lava dome during Peléan activity?Answer: A fast-moving pyroclastic flow of hot gas, ash, and rock fragments.
4. What is a base surge in a Surtseyan eruption?Answer: A ground-hugging cloud that spreads outward as a dense eruption column collapses.
5. Which lava form commonly develops when lava cools underwater?Answer: Rounded masses of pillow lava.