The Collaborative International Dictionary of English v.0.48:

Quaking \Quak"ing\,
   a. & n. from Quake, v.
   [1913 Webster]

   Quaking aspen (Bot.), an American species of poplar
      (Populus tremuloides), the leaves of which tremble in
      the lightest breeze. It much resembles the European aspen.
      See Aspen.

   Quaking bog, a bog of forming peat so saturated with water
      that it shakes when trodden upon.

   Quaking grass. (Bot.)
   (a) One of several grasses of the genus Briza, having
       slender-stalked and pendulous ovate spikelets, which
       quake and rattle in the wind. Briza maxima is the large
       quaking grass; Briza media and Briza minor are the
       smaller kinds.
   (b) Rattlesnake grass (Glyceria Canadensis).
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Quake \Quake\, v. i. [imp. & p. p. Quaked; p. pr. & vb. n.
   Quaking.] [AS. cwacian; cf. G. quackeln. Cf. Quagmire.]
   1. To be agitated with quick, short motions continually
      repeated; to shake with fear, cold, etc.; to shudder; to
      tremble. "Quaking for dread." --Chaucer.
      [1913 Webster]

            She stood quaking like the partridge on which the
            hawk is ready to seize.               --Sir P.
                                                  Sidney.
      [1913 Webster]

   2. To shake, vibrate, or quiver, either from not being solid,
      as soft, wet land, or from violent convulsion of any kind;
      as, the earth quakes; the mountains quake. " Over quaking
      bogs." --Macaulay.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "quaking":
   agitation, ague, aquiver, aspen, bumpiness, chattering,
   chills of fear, chorea, cold creeps, cold shivers, cold sweat,
   creeps, didder, disquiet, disquietude, dithers, fear and trembling,
   fidgetiness, fidgets, fits and starts, flutter, goose bumps,
   gooseflesh, heartquake, heaving, horripilation, inquietude,
   jactation, jactitation, jerkiness, jimjams, joltiness, nervousness,
   palpitation, palsied, palsy, panting, perturbation, pitapat,
   pitter-patter, quaver, quavering, quavery, quiver,
   quiver of terror, quivering, quivery, restlessness, shakes,
   shaking, shaky, shiver, shivering, shivers, shivery, shudder,
   shuddering, spasms, succussatory, succussion, succussive, sweat,
   thrill of fear, throb, throbbing, tremble, trembling, trembly,
   tremor, tremulant, tremulous, tremulousness, trepidation,
   trepidity, twitter, uneasiness, unrest, vibrating, vibration,
   wobbly