underthrust

 
Pronunciation: /ˈʌndəθrʌst/
Geology

verb (past and past participle underthrust)

[with object]
  • force (a crustal plate or other body of rock) beneath another formation: the Farallon plate was being underthrust beneath the North American plate (as noun underthrusting) this sediment may be deformed by the underthrusting
  • be forced underneath (another formation): plate X is underthrusting plate Y in a NE direction

noun

  • an instance of such forced movement: the westward underthrust of the Pacific Ocean plate