[1] : The Collaborative International Dictionary of English v.0.48

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.
   1913 webster

   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.
      1913 webster
see also:
earthdin earthquave earthshock earthquake alarm 

Alarm >> A Words
Alarm, definition of term: Alarm
alarm_pag1.html

Earthquake >> E Words
Earthquake, definition of term: Earthquake
earthquake_pag1.html

Alarm System >> A Words
Alarm System, definition of term: Alarm System
alarm+system_pag1.html