Rift

v. burst open, split, cleave

n. split, cleft, fissure, crevice; break in friendly relations; disagreement that causes a break in friendly relations

In geology, a rift is a place where the Earth's crust and lithosphere are being pulled apart. Typical features are a central linear downdropped fault segment, called a graben, with parallel normal faulting and rift-flank uplifts on either side forming a rift valley. The axis of the rift area commonly contains volcanic rocks and active volcanism is a part of many but not all active rift systems. Rifts are distinct from Mid-ocean ridges, where new oceanic crust and lithosphere is created by seafloor spreading. In rifts, no crust or lithosphere is produced. If rifting continues, eventually a mid-ocean ridge may form, marking a divergent boundary between two tectonic plates. Failed rifts are ancient to modern features where continental rifting began, but then failed to continue. Typically the transition from rifting to spreading develops as three converging rifts over a hotspot. Two of these evolve to the point of seafloor spreading, while the third ultimately fails, becoming an aulacogen.
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Noun
1. a gap between cloud masses; "the sun shone through a rift in the clouds"
(hypernym) opening, gap
2. a narrow fissure in rock
(hypernym) crack, cleft, crevice, fissure, scissure
3. a personal or social separation (as between opposing factions); "they hoped to avoid a break in relations"
(synonym) rupture, breach, break, severance, falling out
(hypernym) separation, breakup, detachment

p. p. of Rive.
  

(v. t.)
To cleave; to rive; to split; as, to rift an oak or a rock; to rift the clouds.
  

(v. i.)
To burst open; to split.
  

(v. i.)
To belch.
  

(n.)
An opening made by riving or splitting; a cleft; a fissure.
  

(n.)
A shallow place in a stream; a ford.
  

  frit