Read the following text carefully and answer the questions below.

Earthquakes

    Earthquakes being the most deadly natural hazards strike without any prior warning leaving catastrophe in their wake with terrible loss of human lives as well as economic loss.

    Technically, an earthquake (also known as tremor, quake or temblor) is a kind of vibration through earth's crust. These powerful movements trigger a rapid release of energy that creates seismic waves that travel through the earth. Earthquakes are usually brief, but may repeat over a long period of time fearth science 2001).

    Earthquakes are classified as large and small. Large earthquakes usually begin with slight tremors but rapidly take form of violent shock. The vibrations from a large earthquake last for few days known as aftershocks. Small earthquakes are usually slight tremors and do not cause much damage. Large earthquakes are known to take down buildings and cause death and injury (Richter 1935). According to some statistics, there may be an average of 500.000 earthquakes every year but only about 100,000 can be felt and about 100 or so can cause damage each year.

    Earthquakes are dreaded by everyone.

What do paragraph 2 and 3 discuss on?