Tectonics: Earthquakes

Earthquakes are one of the most frightening and power natural disasters.
They occur along tectonic plate boundaries in the same way of volcano's. As the plates move pressure in the earth builds and the tension is released via earthquakes. This map shows the global position of the plates.

The area in the earth where the earthquake starts is called the focus or the hypocentre. The centre of the quake on the surface is called the epicentre. I have previously considered the merging of coming together of plates in the blog entitled 'plate tectonics' (not unsurprisingly!) so i am just going to look at the measuring of quakes, the types and then the effects in the next blog.

The machine used to record the power of an earthquake is a seismometer and the value that is placed is assigned under the Reciter scale, the higher the score on the scale the more serious the earthquake. Low score quakes can occur frequently on certain boundaries, with limited damage.

There are 2 types of earthquake with different types of waves of energy. The first is when the waves create a rolling up and down motion called Rayleigh waves and Love waves that cause the ground to twist from side to side. There are earthquakes that occur on land and out at sea and it is the latter that then lead to a tidal wave AKA a tsunami. As well as the initial quake there are also aftershocks that may not be as powerful but can be devastating.

When looking to teach this subject there are many recent examples of severe earthquakes e.g.China's south-western Sichuan province in May 2008 measured 7.8)and tsunamis e.g. Thailand on December 26, 2004. Consideration of the cause/origins and human consequences should bring the subject to life and make it very memorable.