1 : Surface area is a country's total area, including areas under inland bodies of water and some coastal waterways. 2  Irrigated land: The number of square kilometers of land area that is artificially supplied with water. 3  Population density: People per square kilometre, in 1999. 4  At this time the world average was 14.42.
A ground fault is an inadvertent contact between an energized conductor and ground or equipment frame. The return path of the fault current is through the grounding system and any personnel or equipment that becomes part of that system.
When rocks break and move suddenly, the energy released causes an earthquake. Faults may occur at the Earth's surface or deeper in the crust. Faults are found alone or in clusters, creating a fault zone. Figure 7.14: Faults are easy to recognize as they cut across bedded rocks.