Shield volcanoes are short and
wide at the bottom, and have
gentle eruptions.
Composite
Composite volcanoes are tall and
narrow at the bottom, and have violent
eruptions.
Formation
How
They are formed by convection currents in
the mantle pulling or pushing the plates
away or towards each other.
Where
Constructive and Destructive margins
What
An opening in the earths crust through
which molten lava, ash and gases are
ejected.
Tectonics
Types
Continental
Continental is
thicker, less dense
and older.
Oceanic
Oceanic is thinner,
denser and newer.
Earthquakes
What
A sudden and often
violent shift in the
rocks forming the
earths crust, which
is felt at the surface.
Formation
Where
Earthquakes can happen
along any type of plate
boundary.
How
Earthquakes occur when tension is
released from inside the crust. Plates
do not always move smoothly
alongside each other and sometimes
get stuck. When this happens
pressure builds up.
Tsunamis
What
A tsunami is a large ocean wave usually
caused by an underwater earthquake or a
volcanic explosion. Tsunamis are NOT tidal
waves. Tidal waves are caused by the forces
of the moon, sun, and planets upon the
tides, as well as the wind as it moves over
the water.
Formation
Where
Tsunamis occur most
often in the ocean from
undersea earthquakes or
landslides.
How
Tsunami waves are formed as the
displaced water, attempts to find a stable
position again. Undersea earthquakes, can
cause tsunami waves to form as water
attempts to find a stable position.