booby trap vs land mine

booby trap

noun
  • An unforeseen source of danger; a pitfall. 

  • An antipersonnel device deliberately hidden or disguised as a harmless object. 

  • A practical joke by which something is made to fall upon someone entering through a door, or the like. 

land mine

noun
  • A critical subject or situation with concealed or unpredictable implications. 

  • A piece of exercise device consisting of a pivoting tube attached to the ground to which a barbell can be fitted to lift it off the ground. 

  • A mine that is placed on land and designed to explode when stepped upon or touched. 

How often have the words booby trap and land mine occurred in a corpus of books? (source: Google Ngram Viewer )