badlands vs malpais

badlands

noun
  • An arid terrain characterized by severe erosion of sedimentary rocks. 

malpais

noun
  • Land akin to badlands, but having volcaniclastic rather than sedimentary rocks. 

  • Land having an underlayer of basaltic lava and little or no soil. 

How often have the words badlands and malpais occurred in a corpus of books? (source: Google Ngram Viewer )