alarm bell vs disturbance

alarm bell

noun
  • A sudden awareness of danger. 

  • Used other than figuratively or idiomatically: see alarm, bell. 

disturbance

noun
  • The act of disturbing, being disturbed. 

  • A noisy commotion that causes a hubbub or interruption. 

  • Something that disturbs. 

  • An interruption of that which is normal or regular. 

  • A serious mental imbalance or illness. 

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