subsequently vs thereupon

subsequently

adv
  • Following, afterwards in either time or place. 

  • Accordingly, therefore (implying a logical connection or deduction), consequently. 

thereupon

adv
  • Following that; forthwith; in sequence, but not necessarily in consequence. 

  • In consequence, or by reason, of that; therefore. 

  • Upon that; thereon. 

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