Download Volcanoes and Earthquakes.

THE EARTHS CRUST
The earths crust is in constant motion.
Volcanoes and earthquakes arise as
sections of crust push toghether or
pulled apart. Volcanoes and earthquakes
are more common in certain parts of
the world. By monitoring ground
vibrations scientists can sometimes
Predict a massive earthquake or volcanic
eruptions and warn people.
THE SOLID SURFACE
The solid surface layer of the Earth is
known as the crust and ranges 5km
to 80 km in thickness. Beneath the
crust is the mantle which is 2,900km
thick and made up of molten rock.
The core is the centre of the Earth
and is mostly made of iron. It has
a liquid outer core and a solid inner
core and is around 4,500C .
VOLCANOES
Volcanoes form when molten rock is
pushed up trough the crust.
When subduction the occurs, the
oceanic plate melts underground,
creating a supply of molten rock.
The rock is then released as lava
in a volcanic eruption.
EARTHQUAKES
The earths crust is broken up into a
number of separate plates.
Earthquakes are caused when two
plates collide. The strongest
earthquakes occur along breaks in
the earths crust called fault lines.
FRICTION
Earthquakes are the result of
frictional forces as two plates
move side by side. The plates
judder as they slide past each
other and each judder causes an
earthquake.