alluvion vs emergency

alluvion

noun
  • The increase in the area of land due to the deposition of sediment (alluvium) by a river. 

emergency

noun
  • Arising from or used in an emergency. 

  • A situation which poses an immediate risk and which requires urgent attention. 

  • An individual brought in at short notice to replace a member of staff, a player in a sporting team, etc. 

  • The department of a hospital that treats emergencies. 

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