Chapter 7 - Section 1 Flashcards
volcano
A weak spot in the crust where magma has come to the surface.
magma
The molten mixture of rock-forming substances, gases, and water from the mantle.
lava
Liquid magma that reaches the surface; also the rock formed when liquid lava hardens.
Ring of Fire
A major belt of volcanoes that rims the Pacific Ocean.
island arc
A string of islands formed by the volcanoes along a deep-ocean trench.
hot spot
An area where magma from deep within the mantle melts through the crust above it.
Where are most of Earth’s volcanoes found?
Short answer:
at plate boundaries
Long answer:
Most volcanoes form along diverging plate boundaries such as mid-ocean ridges and along converging plate boundaries where subduction takes place.
How do hot spot volcanoes form?
A volcano forms above a hot spot when magma erupts through the crust and reaches the surface.
What features form as an oceanic plate moves across a hot spot?
volcanic mountains
