Hypocenter

A hypocenter or hypocentre ('' ()|below the center}}), also called ground zero or surface zero, is the point on the Earth's surface directly below a nuclear explosion, meteor air burst, or other mid-air explosion. In seismology, the hypocenter of an earthquake is its point of origin below ground; a synonym is the focus of an earthquake.

Generally, the terms ''ground zero'' and ''surface zero'' are also used in relation to epidemics, and other disasters to mark the point of the most severe damage or destruction. The term is distinguished from the term zero point in that the latter can also be located in the air, underground, or underwater. Provided by Wikipedia