Hypocenter

[3] 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.

[4] The term "ground zero" originally referred to the hypocenter of the Trinity test in Jornada del Muerto desert near Socorro, New Mexico, and the atomic bombings of Hiroshima and Nagasaki in Japan.

At Hiroshima, the hypocenter of the attack was Shima Hospital, approximately 800 ft (240 m) away from the intended aiming point at Aioi Bridge.

In advance of the 10th anniversary of the attacks, New York City mayor Michael Bloomberg urged that the "ground zero" moniker be retired, saying, "…the time has come to call those 16 acres [6.5 hectares] what they are: The World Trade Center and the National September 11th Memorial and Museum.

The 2013 Chelyabinsk meteor's hypocenter in Russia was more populated than that of Tunguska, resulting in civil damage and injury, mostly from flying glass shards from broken windows.

[10] An earthquake's hypocenter or focus is the position where the strain energy stored in the rock is first released, marking the point where the fault begins to rupture.

[11] The expanding wavefront from the earthquake's rupture propagates at a speed of several kilometers per second; this seismic wave is what is measured at various surface points in order to geometrically determine an initial guess as to the hypocenter.