Page 87 - DK Children's Encyclopedia

Earthquakes SEE ALSO

▸ ▸ Buildings p.48
▸ ▸ Changing world
An earthquake is when the ground shakes. pp.50–51
Earthquakes happen along cracks in the Earth’s ▸ ▸ Earth’s surface
crust, known as faults. Small earthquakes can p.84

barely be felt by humans, but the biggest can ▸ ▸ Inside Earth p.135
cause enormous damage. ▸ ▸ Rocks and
minerals p.214

What causes A fault is a crack in Powerful shaking
the rocks that form
an earthquake? the Earth’s crust. causes buildings to
collapse, breaks up
An earthquake happens when roads, and brings
two huge areas of the ground down power lines.
jerk past one another, making
the ground shake. The crack
between them is called a fault.

The point on the ground
directly above where
the earthquake starts
is called the epicenter.

The ground on either
side of the fault moves Earthquake waves
in opposite directions. travel fast outward
in all directions, making
the ground shake.

The point in the ground
where the earthquake Giant waves
starts is called the focus. The biggest earthquakes happen
under the sea. They make the sea
bulge upward, forming dangerous giant
San Andreas Fault waves, known as tsunamis. Waves can
The San Andreas Fault is a Sea surface be taller than
large crack in the ground that lifts buildings
slices through California. It
marks the join between two
huge pieces of the Earth’s
crust, called plates. Big
earthquakes happen on the
fault about every 10 years.
Earthquake
pushes the seabed up

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