An earthquake is the shaking and vibration of the Earth’s crust due to movement of the Earth’s plates.
Earthquakes are found at constructive, desctructive and conservative plate boundaries. This means they are found in zones around the world.
Latest earthquakes in the world – past 7 days.
Earthquakes occur at plate boundaries because of the build up of friction that occurs are plates try to move past each other and get stuck.
Plate boundary Friction builds up when… destructive margins one plate tries to sink below the other collision zones
plates are pushing together
constructive margins both plates try to move over the mantle conservative margins plates moving alongside each other get stuck
Features of an earthquake
Focus: the point inside the crust where the pressure is released
Epicentre: the point on the Earth’s surface directly above the focus
Seismic waves: the energy released by the earthquake travels in waves
Measuring earthquakes 
The power of an earthquake is measured using a seismometer. This detects the vibrations caused by an earthquake and plots them on a seismograph. The strength or magnitude of an earthquake is measured using the Richter scale which is a logarithmic scale which means that a magnitude 6 earthquake is ten times stronger than a magnitude 5 earthquake, and 100 x stronger than a magnitude 4. This scale allows you to directly compare the magnitude (strength) of an earthquake however, strength of earthquake doesn’t allow correlate with damage. To overcome this the Mercalli scale measures the effects. It has twelve points of the scale (but uses Roman numerals I – XII), to view the different intensities click here.