What is "earthshock"

Earthquake \Earth"quake`\, n. A shaking, trembling, or concussion of the earth, due to subterranean causes, often accompanied by a rumbling noise. The wave of shock sometimes traverses half a hemisphere, destroying cities and many thousand lives; -- called also earthdin, earthquave, and earthshock.

Earthquake alarm, a bell signal constructed to operate on the theory that a few seconds before the occurrence of an earthquake the magnet temporarily loses its power.

n. An earthquake.

Earthshock is the sixth serial of the 19th season in the British science fiction television series Doctor Who, which was first broadcast in four twice-weekly parts from 8 March to 16 March 1982. This serial marks the final regular appearance of Matthew Waterhouse as the Doctor's companion Adric and his climactic death, with the final episode featuring unique silent credits in memory of the character. It is also the first to feature the Cybermen since Revenge of the Cybermen, in 1975.