Reading Comprehension Sheet - Volcanoes And Plate Tectonics printable pdf download

Reading Comprehension Sheet - Volcanoes And Plate Tectonics

Name ____________________________ Date ___________________ Class____________

Ch 3 Sec 1: Volcanoes and Plate Tectonics

Guide for Reading

■ Where are most of Earth’s volcanoes?

■ How do hot spot volcanoes form?

A volcano is a weak spot in the crust where molten material, or

magma, comes to the surface.

Magma is a molten mixture of rock-forming substances, gases,

and water from the mantle.

When magma reaches the surface, it is called lava. When lava

has cooled, it forms solid rock. Lava released during volcanic

activity builds up Earth’s surface.

Volcanoes occur in belts that extend across continents and oceans.

One major volcanic belt is the Ring of Fire, formed by the many

volcanoes that rim the Pacific Ocean. 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:

1. diverging plate boundaries such as mid-ocean ridges &

also on land as in the Great Rift Valley in East Africa.

Along the rift valley, lava pours out of cracks in the ocean

floor, gradually building new mountains.

2. converging plate boundaries where subduction takes place.

Many volcanoes form near converging plate boundaries

where oceanic plates return to the mantle.

Volcanoes may form where:

a. two oceanic plates collide

b. an oceanic plate collides with a continental plate.

Reading Comprehension Sheet - Volcanoes And Plate Tectonics