WHAT IS AN EARTHQUAKE?
The vibration or tremors in the earth’s crust , caused by a sudden release of energy when the rock displaced along a fault.
THE FORMATION OF AN EARTHQUAKE
When two plates move towards or away from each other or slide movement is not smooth cause the friction between the moving plates cause stress to build up in the crust and eventually faulting occurs. The rock breaks and move in sudden jerks along the fracture. The energy which has been stored up in the rocks is suddenly released as shock waves. This cause vibration or tremors of the earth’s surface known as an earthquake.
Shockwaves of the earthquakes
During an earthquake the shock waves spread out in all directions from the point where the earthquake starts.
The point in the earth’s crust at which an earthquake starts is called the focus.
The point on the earth’s crust that is directly above the focus is the epicentre.
The shock waves are the strongest at the epicentre and so the greatest damage in that area.