fall upon vs surround

fall upon

verb
  • to set upon; to attack suddenly 

  • to occur at some particular point in time. 

  • to experience; to suffer. 

surround

verb
  • To enclose or confine something on all sides so as to prevent escape. 

  • To encircle something or simultaneously extend in all directions. 

noun
  • Anything, such as a fence or border, that surrounds something. 

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