Where do earthquakes occur?

Earthquakes occur at all three types of plate margin. They are caused by pressure that builds up at all three plate margins or by the upwelling of magma during a volcanic eruption. The plates eventually kerk past each other, sending out shock waves.

The shock waves spred out from the focus. The epicentre is the area that spreads out right across the focus. Near the epicentre the shock waves are stronger and cause more damage.

The amount of energy realeased by an earthquake (its magnitude) is measured using a Richter scale. The scale doesn't have an upper limit and its logarithmic (this means an earthquake with a magnitude is ten times powerful then a magnitude of 4)

Primary Impacts:

• Buildings and bridges collapse
• People are injured or killed by buildings and bridges collapsing
• Roads, railways, ports and airports are damaged
• Electricity cables are damaged, cutting off supplies
• Gas pipes are broked, causing leaks and cutting off supplies
• Telephone poles and cables are destroyed
• Underground water and sewage pipes are broken, causing leaks and cutting off supplies.

Secondary Impacts:

• Earthqaukes can trigger landslides and tsunamis- these destory more buildings and cause more injuries and deaths
• Leaking gas can be ignited, starting fires
• People are left homeless
• People may suffer psychological problems if they know people who diesd or if they lose their home etc.
• There's a shortage of clean water and a lack of proper sanitation-this makes it easier for diseases to spread.
• Roads or blocked or destroyed so aid and emergency vehicles can't get through 
• Businesses are damaged or destroyed causing unemployment