The best replacement for earthquake is aftershock.

The best alternatives to earthquake are rated as following:
★★★★★  aftershock
★★★★★  tornado
★★★★  magnitude pokemon
★★★★  hurricane
★★★★  volcano
★★★  yokozuna
★★★  earth power
★★  tremor
★★  kitao
★★  dig
★★  sonic boom
★★  bulldoze
★★  tsunami
★  rock slide
★  land's wrath
★  drill run
★  earthquake
★  jake the snake
★  stone edge
★  haiti earthquake
★  call of the ancients
  earthquakes
  volcano which is more dangerous
  adam bomb
  quarry blast
  crunch
  tugboat
  rubick
  chile earthquake
  japan earthquake
  earth movement
  nuclear bomb
  volcanoes

Your alternative for earthquake is not listed? Suggest!
Speaking about earthquake, one probably shouldn't forget about highest magnitude.

Other search terms related to earthquake and their ratings are:
★★★★★ highest magnitude
★★ tsunami
★★ greatest magnitude
★ magnitude
You have in mind a companion for earthquake and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of earthquake in all years. Click on graph for more.
earthquake
aftershock
tornado