earthquake vs seism

earthquake

noun
  • A shaking of the ground, caused by volcanic activity or movement around geologic faults. 

  • Such a quake specifically occurring on the planet Earth, as opposed to other celestial bodies. 

verb
  • To undergo an earthquake. 

seism

noun
  • A shaking of the Earth's surface; an earthquake or tremor. 

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