Epicenter

epicentre (US), epicenter

the point on the earth's surface directly above the focus of an earthquake or underground nuclear explosion

---

epicenter [′ep·ə‚sen·tər]

(geology)

A point on the surface of the earth which is directly above the seismic focus of an earthquake and where the earthquake vibrations reach first.

(mathematics)

The center of a circle that generates an epicycloid or hypocycloid.

---

Epicenter 

(1) The projection of the hypocenter of an earthquake onto the earth’s surface (seeHYPOCENTER). The location of the epicenter is determined from recordings by seismic stations, and the epicentral region is determined by the degree of destruction on the surface. Epicenter maps showing the magnitudes of earthquakes are used in seismic zoning. (See alsoEARTHQUAKES.)

(2) The projection onto the earth’s surface of the center of an atmospheric (underwater or underground) nuclear explosion.