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.