What is an Earthquake?

Nature has some terrible and extreme forms of expression such storms, terrifying winds and floods. One of the most severe and fear inducing natural events is the earthquake and the various levels of devastation it can leave behind.

With very little warning an earthquake can strike at any time of the day or night with huge force and energy and can lay waste to entire towns and cities and lead to a significant loss of life. This was seen most recently in Haiti. The Haiti disaster was compounded by the fact that it was such a densely packed city and built on rock that allowed energy to pass through it with less resistance.

Earthquakes are occurring all year round on a frequent basis more than people would actually think. There is an average figure of around 700,00 per year but most of these are small tremors and go undetected by most of us. There are a number of destruction causing quakes each year though.

The areas of occurrence are generally along the boundaries of where tectonic plates meet; these are the slabs of the Earth's crust that move and bump into each other deep below us and they are constantly moving. The 'crust' or 'upper mantle' undergoes stress due to the tectonic shifting and this causes energy to move upward creating shock waves breaking up the rock - which we experience as earthquakes!

The really big quakes happen about once every decade and these are classed as severe and leave a lot of chaos in the aftermath.