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]

The Collaborative International Dictionary of English v.0.48:

Earthquake \Earth"quake`\, a.
   Like, or characteristic of, an earthquake; loud; startling.
   [1913 Webster]

         The earthquake voice of victory.         --Byron.
   [1913 Webster]

WordNet (r) 3.0 (2006):

earthquake
    n 1: shaking and vibration at the surface of the earth resulting
         from underground movement along a fault plane of from
         volcanic activity [syn: earthquake, quake, temblor,
         seism]
    2: a disturbance that is extremely disruptive; "selling the
       company caused an earthquake among the employees"

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "earthquake":
   apoplexy, breakup, cataclysm, climax, convulsion, diastrophism,
   disaster, fit, overthrow, paroxysm, quake, quaker, shake, shock,
   spasm, stroke, temblor, tidal wave, tremor, tsunami, upheaval



The Free On-line Dictionary of Computing (30 December 2018):

earthquake

   (IBM) The ultimate real-world shock test for computer
   hardware.  Hackish sources at IBM deny the rumor that the
   San Francisco Bay Area quake of 1989 was initiated by the
   company to test quality-assurance procedures at its California
   plants.

   [Jargon File]

   (1995-04-22)


Easton's 1897 Bible Dictionary:

Earthquake
   mentioned among the extraordinary phenomena of Palestine (Ps.
   18:7; comp. Hab. 3:6; Nah. 1:5; Isa. 5:25).

     The first earthquake in Palestine of which we have any record
   happened in the reign of Ahab (1 Kings 19:11, 12). Another took
   place in the days of Uzziah, King of Judah (Zech. 14:5). The
   most memorable earthquake taking place in New Testament times
   happened at the crucifixion of our Lord (Matt. 27:54). An
   earthquake at Philippi shook the prison in which Paul and Silas
   were imprisoned (Act 16:26).

     It is used figuratively as a token of the presence of the Lord
   (Judg. 5:4; 2 Sam. 22:8; Ps. 77:18; 97:4; 104:32).