Chapter 5Lesson 2

The Moving Crust

Pgs. 212-221

Earth’s surface is broken into several large pieces called

tectonic plates.

A fault is a crack in the crust where the plates meet.

These plates are constantly slowly moving. This movement creates changes in the Earth’s

surface.

A fault-block mountain forms when one plate slides on top of

another plate as they push together.

If two plates push together and both plates push up, a fold

occurs.

Folded Mountains

When a sudden movement along a fault occurs, an

earthquake takes place. This is cause by pressure being built

up for a long time along a fault.

The energy released during an earthquake travels in waves through the earth. These are

called seismic waves.

Scientists use an instrument called a seismograph to

measure seismic waves.

The magnitude of an

earthquake is how strong the earthquake is.

The Richter Scale is how

the magnitude of earthquakes

are rated.

If an earthquake takes place below the ocean, and is

powerful enough, it can cause a giant wave called a tsunami.

A volcano is a mountain that builds up around an opening in

the Earth’s crust.

Most volcanoes occur at the edges of tectonic plates where magma (melted rock) pushes

towards the surface.

A volcanic eruption can send out melted rock (lava), gases, ash,

or rocks into the air.