Earthquakes

Summary:

~ Earthquakes, or seismic tremors occur when energy stored within the Earth suddenly releases.

~ The energy stored is usually in the form of strain in rocks. This energy is transmitted to the surface of the earth by earthquake waves.

~ The centre where the earthquake energy release is called focus.

~ Epicentre is the highest energy of seismic waves occur.

~ There are two kinds of earthquakes : tectonic and volcanic.

~ Tectonic earthquakes are caused by the sudden release of energy stored within the rocks a long a fault. The released energy is produced by the strain on the rocks due to movement within Earth.

~ Volcanic earthquakes occur near active volcanoes but have the same fault slip (or landslide) mechanism as tectonic earthquakes.