Volcanism Flashcards
Define crater
Bowl shaped depression at top of volcano, formed as eruption builds up around vent
Caldera
Huge crater, can’t see volcano anymore because it’s fully caved in
Define a shield volcano
Largest broad, slight dome, low viscosity
Define cinder cones
Smallest, steep comical piles of pyreclastic debris/rubble
Define Stratovolanoes
Intermediate, made of composite layers (cone shape with steeper slopes)
Define viscosity
A lava’s resistance to flow
Define pillow lavas
Mafic/basaltic lava that extruded underwater to form blob -like shapes, or pillows, which typically have a glassy rind.
What is pyroclastic debris
Unconsolidated fragments resulting from an eruption
What is pyroclastic flow?
A fast-moving avalanche that occurs when hot volcanic ash and pyroclastic debris mix with air and flow down the side of a volcano
What volcanic gases
Occurs because most magma contains dissolved gas!
Define Lahars
A thick slurry formed when volcanic ash and debris mix with water, either in rivers or from rain or melting show on the flank of a volcano
Define magma chamber
A large, irregularly-shaped space below ground filled with magma
Define Fissure
A conduit in a magma chamber in the shape of a long crack through which magma rises and erupts at the surface
Define effusive eruptions
Outpouring of lava
Define eruptive styles
Release pressure catastrophically
