Lava released during volcanic activity builds up earth's surface.
Volcanic belts form along the boundaries of Earth's plates.
At plate boundaries, huge pieces of the crust diverge (pull apart) or converge (push together). As a result, the crust often fractures, allowing magma to reach the surface.
Most volcanoes form along diverging plate boundaries such as mid-ocean ridges and along converging plate boundaries where subduction takes place.
Along the _____________________, lava pours out of cracks in the ocean floor, gradually building _______________________.
Eastern seaboard, new states
rift valley, new mountains
Many volcanoes form near ________________ plate boundaries where oceanic plates return to the _____________________.
Volcanoes often form where:
two oceanic plates collide
an oceanic plate collides with a continental plate
near boundaries where two oceanic plates collide
near converging plate boundaries where oceanic plates return to the mantle
Through subduction, the older, denser plate sinks beneath a deep-ocean trench into the mantle. Some of the rock above the subducting plate melts and forms magma.
Because magma is more dense than the surrounding rock, it rises toward the surface.
When magma breaks through the ocean floor, it creates
Resulting volcanoes formed along a deep ocean trench are called a
ring of fire
Volcanoes occur where an oceanic plate is __________________________ beneath a continental plate.
Some volcanoes result from "hot spots" in Earth's mantle.
A volcano forms above a hot spot when water erupts through the crust and reaches the surface.
A hot spot in the ocean floor can gradually form a series of volcanic mountains.
The _____________________ Islands formed over ______________ of years as the Pacific Plate drifted over a hot spot.
Hot spots can form under continents.
_______________________________________ in Wyoming marks a hot spot under the North American plate.
Yellowstone National Park