You will be successful if you can:
• Describe the reasons as to why earthquakes
and volcanoes are unpredictable.
• Recall that earthquakes, volcanoes and
mountain building occur at the edges of
• Be able to describe how the movement of
tectonic plates contribute to the rock cycle.
The Earth’s outer layer is
made up of a dozen giant
SLABS of rock, and some
These are called TECTONIC
There are more than 30 000 earthquakes
of these is
The tectonic plates can move in 3 ways:
MOVE AWAY from Earthquakes are common at all
each other. Usually moving plate boundaries. The
under the sea, at most destructive happen at
OCEANIC RIDGES. subduction boundaries: these
may cause TSUNAMIS.
PUSH TOGETHER in
mountains like the
SLIDE PAST each
other, like the San
Andreas fault in
A volcano is a vent (or valve) in the
Earths surface. It erupts magma,
which forms lava or ash.
They are also
common at PLATE
where the Earth’s
crust is stretched,
Crust Mantle Core
Heat Low density Tectonic plates
Africa S America Rock types
Oceanic Plate Fossils High Density
Magnetic Continental Radioactive
reversal plate Decay
Complete the Geohazards project on
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