Earth Mother vs Mother Earth

Earth Mother

noun

  • The Great Goddess of the Earth and fertility. 

  • A figurine or depiction of this goddess. 

Mother Earth

name

  • The goddess of the earth in various cultures. 

  • The personification of the Earth, (chiefly) conceived as a fertile, nurturing, and loving mother. 

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