decrepitate vs flare up

decrepitate

verb
  • To roast (a salt or mineral) until it stops crackling in the fire. 

  • Of salts and minerals, to crackle when heated, indicating a sudden breakdown of their particles. 

flare up

verb
  • To burn brightly again. 

  • To become more intense suddenly. 

  • To burst out suddenly, as in anger. 

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