Please, speak slowly and clearly.
Lightning: Lightning is characterized by the discharge of electricity between rain clouds or between a rain cloud and the earth. It is usually seen as an arc of extremely bright light which can be many kilometers in length; however, there are other forms as well. Accompanying the lightning is the giant roar of thunder. The thunder is caused by the expansion of air that has been heated by the lightning which then collides with cooler air, creating the sound of an explosion.
Thunderstorms are the most common types of storms, and thunder itself, although frightening, is not dangerous. It is the lightning that causes the problems. Lightning and thunder occur together, however we hear the thunder after we see the lightning. Sound waves travel about one mile in five seconds, while light travels at more than 186,000 miles per second. Therefore, lightning is seen immediately when it occurs, and thunder is heard a little later.
The different sounds of thunder (deep roar/loud crash) is caused by the different types of lightning, for example, the thunder that has the sharp crackle like sound is caused when the large trunk of lightning forks into many branches.
Earthquake: is a shaking of the ground caused by the sudden dislocation of material within the earth's outer layer, or crust. When forces pushing on a mass of rock overcome the friction holding the rock in place and blocks of rock slip against each other a earthquake may occur. Some earthquakes are so slight, and some occur in such remote areas, that they are barely felt. Others are so violent that they cause extensive damage.
Earthquakes are caused by stresses below the earth's outer surface. These stresses usually build up until the rocks fracture along a "fault plane." This causes vibrations, also known as seismic waves. Seismic waves will then travel in all directions from the area of fracture. In large earthquakes seismic waves may be detected over the entire earth.
Earthquakes can be caused by volcanoes in certain cases. Nuclear explosions under the ground can create waves that are very similar to natural seismic waves. The seismic energy created in a atomic bomb is one hundred-thousandth that of the largest earthquake.
Earthquakes take place or have taken place in all parts of the world. Frequent activity occurs along certain belts. 80% of all seismic energy is generated from a belt that is found at the border of the Pacific Ocean. The intensity of an earthquake is measured in terms of its geological effects and the overall damage it brings. There are two major scales in which earthquakes are measured. These two scales are the Mercalli Scale and the Richter Scale.
