Volcanoes and Plate Tectonics

Volcanoes and Plate Tectonics

Question Where are volcanoes found?

What is a hot spot?

AnswerVolcanoes form along the boundaries of Earth's plates.

An area where material from deep within the mantle rises, and then melts, forming magma.

Ring of Fire

a weak spot in the crust where molten material, or magma, comes to the surface

What is a volcano?

What is Magma?

A molten mixture of rock-forming substances, gases, and water from the mantle.

When magma reaches the surface.

When does magma become lava?

a major volcanic belt formed by the many volcanoes that rim the Pacific Ocean.

What is the Ring of Fire?

along diverging plate boundaries such as mid-ocean ridges and along converging plate boundaries where subduction takes place.

Where do volcanoes come from?

Along the rift valley, lava pours out of cracks in the ocean floor, gradually building new mountains.

Describe how volcanoes form along the mid-ocean ridge?

Volcanoes can form along diverging plate boundaries.

True or false?

Many volcanoes form near converging plate boundaries where oceanic crust returns to the mantle.

True or false?

When 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 the magma is less dense than the surrounding rock, it rises toward the surface. Eventually, the magma breaks through the ocean floor, creating volcanoes. Volcanoes can also form where oceanic crust is subducted beneath continental crust.

How does subduction at converging plate boundaries lead

to the formation of volcanoes

Volcano boundaries where two oceanic plates collide to create a string of islands

Island arc?

Japan, New Zealand, Indonesia, the Philippines, the Aleutians, the Caribbean islands

Name of 6 major island arcs?

an area where material from within the mantle rises and the melts, forming magma

What is a hot spot?

They formed over millions of years as the Pacific plate drifted over a hot spot.

How did the Hawaiian Islands form??

When lava that has erupted from a volcano cools, it forms solid rock. In this way, volcanoes add new rock to existing land and form new islands.

How do volcanoes change Earth’s surface?

At the boundaries where plates diverge (pull apart) or converge (push together), the crust is weak and fractured, allowing magma to reach Earth's surface

Why do so many of Earth’s volcanoes occur at plate boundaries?

Lava erupted from the hot spot and built a volcanic island. The Pacific plate is slowly moving over the hot spot, so it carried the island away from the spot. Another volcanic island formed at the hot spot and then was carried away. Over time, a chain of islands formed.

Explain how hot spots created the Hawaiian Islands.

Magma is molten, rock-forming material underground. Magma that reaches the surface is called lava.

What is the difference between magma and lava?

a weak spot in Earth's crust where magma comes to the surface

Define volcano

a belt of many volcanoes that rim the Pacific Ocean

Define Ring of Fire

a chain of volcanic islands that forms at the boundary where two oceanic plates push together and one plate subducts under the other plate

Define island arc