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In an average year approximately 12 million
earth quakes occur around the world, but
only 100 of these have significant imact on
human activity.…read more

Slide 3

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Most earthquakes are caused by sudden movements
in the earth, this could be caused along a fault
plane or as a result of the upwelling of magma in a
volcanic eruption.
The movement is because of the release of stress in
rocks that build up over a period of time. These are
called `shocks' or seismic waves.…read more

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The point at which the pressure
released is called the focus.
This is the centre of the earthquake. The point
immediately above the focus, on the Earths
surface, is called the epicentre.
The seismic waves radiate out from the focus and
decreases in strength as they spread.…read more

Slide 5

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Ground Shaking: this is the main hazard created by
earthquakes. It's severity depend of factors such
as strength of the earthquake, distance from the
epicentre, and local geological conditions. The
longer the shaking the more damage is caused.
Landslides, rock and snow avalanches: occurs in
mountainous areas where slopes are weakened
by shaking and eventually give way. Landslides
can block roads and fill reservoirs like in the
Sichuan earthquake in China.…read more

Slide 6

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Tsunamis: when earthquakes occur beneath the
sea it causes seismic sea waves. They can travel
at enormous speeds and cause devastation along
the coast. They can lead to tidal waves which can
kill many people.
Liquefaction: Shockwaves can cause groundwater
to rise to the surface turning soft ground to mud.
Any buildings built on clay, for example, sink
and collapse.…read more

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