An earthquake is a violent tremor in the earth crust which send out a series of vibrating waves in all directions.
These are sudden movement or vibrations of in the earth crust. They occur as a result of disturbances within and below the earth crust
CAUSES OF EARTHQUAKES
Most earthquakes one caused by sudden movement within the earth crust particularly where there are fractures of faults, stress is built up within the earth crust when a certain point of tension or intensity is reached, cracked or ships occurs within the earth crust. This produce the shock effect that sands but vibrations.
The point at which the shock originates is caved in a nut shell earthquakes are caused by the development of faults or cracks in the crust which results from the collision between the tectonic plains.
The movement of molten rock below or within crust or the sudden release or stress which are slowly built up along the plain. The point at which the shuck originates is called Origin or Focus and the point on the earth surface directly above the focus or where the shock waves first meet the surface with Intensity of earthquake is called seismograph. This instrument records the vibration produced by an earthquake. The effect produced by the earthquakes is referred to as Intensity. The magnitude of shock of the earthquake which refers to the total amount of energy released is measured according to Richter’s scale.
When earthquakes occur on the seafloor for example, it sets up huge waves called tsunamis. This waves at times more than 10m high invade adjacent costal lands drowning people and livestock and pull down structure. For example on December 27, 1939 an earthquake and accompanying waves killed 50,000 people and destroy 100,000 homes in Turkey.
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