Download VOLCANOES STUDY GUIDE Test 1/14/15 Key Words • Volcano

VOLCANOES STUDY GUIDE
Test 1/14/15
Key Words
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Volcano-opening in Earth’s crust where one plate goes over another plate
Lava-magma that reaches Earth’s surface
Island chain-line of volcanic mountains
Hot spot-stationary pool of magma
Island arc-where an ocean-floor plate is pushed under another ocean-floor
plate
Types of Volcanoes
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Active volcano-currently erupting or has recently erupted
Dormant volcano-has not erupted in a long time
Extinct volcano-has stopped erupting
Shield Volcano-built by thinner, fluid lava that spreads over a large area
Cinder-Cone Volcanoes-built by thick lava, cone shape mountain, steep
sides
 Composite Volcanoes-built by layers of ash and cinders sandwiched
between layers of hardened lava
Need to know
 Most of Earth’s volcanoes are located at edges of plates.
 A string of volcanoes at plate boundaries around the Pacific Ocean is known
as the Ring of Fire.
 The hot rock sometimes erupts through openings in Earth’s surface as a
vent.
 Magma pushed into a thick sill can form a dike.
 The largest underground magma formations are batholiths.
 When mountains grow high enough to break the ocean’s surface, they
become volcanic islands.