volcanoes

basaltic lava is [felsic/mafic]

mafic

basaltic lava is [very/kind of/not] flowy

very

basaltic lava is [thin/medium/steep]

thin

basaltic lava spreads out [a lot/a bit/not at all]

a lot

andesitic lava is [felsic/mafic]

intermediate

andesitic lava is [very/kind of/not] flowy

kind of

andesitic lava spreads out [a lot/a bit/not at all]

a bit

andesitic lava is [thin/medium/steep]

medium

rhyolitic lava is [felsic/mafic]

felsic

rhyolitic lava is [very/a bit/not at all] flowy

not at all

rhyolitic lava is [thin/steep]

steep

pyroclastic debris can be

lapilli, ash, blocks, bombs

what 2 reasons do gases come out of solution as magma reaches the surface?

pressure and crystal mineralization (indirect)

viscosity controls (gas)…

which gases leave magma creating steam

three kinds of volcanoes

cinder cone, shield, composite

how are cinder cones formed

successive layering of solid ejecta (ash, lapilli, tephra)

relative size of cinder cone volcanoes

short and small

what kind of lava do shield volcanoes have

basaltic

what kind of lava do cinder cone volcanoes have

basaltic

how are shield volcanoes formed

layers of successive basaltic lava flows

relative shape of shield volcanoes

big, long, gentle slope, thin layers

composite volcanoes are also called

stratovolcanoes

what kind of lava do composite volcanoes have

felsic lava and pyroclastic debris (tephra)

how are composite volcanoes formed

successive layers of lava and tephra

relative size of composite volcanoes

big and steep

what happens when all of the magma is used up from a magma chamber?

the surface collapses on itself, creating a caldera

what can lava erupt out of

a conduit or a fissure

kinds of eruptions

effusive, small explosive, immense explosive

effusive eruptions

lava pours or fountains out of a vent or fissure

composition of effusive eruptions

basalt

viscosity of effusive eruptions

low

what kind of volcano has effusive eruptions

shield

examples of explosive eruptions

hawaiian, strombolian, vulcanian, plinean

explosive eruption composition

felsic

explosive eruption viscosity

high

volcanoes are located at

mid ocean ridges

volcanic hazards

lava, pyroclastic, lahars, earthquakes, blast, gas

relative distance of hazards

lava flow, mud flow, pyroclastic flow, ash fall

signs of volcanic eruptions

gas composition, changes in shape, changes in heat/temperature, earthquakes

recurrence interval formula

recurrence interval = 1/percent chance it occurs in a given year

limitations of recurrence interval

implies independence

what does recurrence interval mean

helps understand percent chance an event may occur each year