zemljotres

1. earthquake
   Sinoć se u Kraljevu osetio jak zemljotres. — A strong earthquake was felt in Kraljevo last night.
   Zemljotres je oštetio stotine kuća. — The earthquake damaged hundreds of houses.
2. (figuratively) upheaval; shake-up
   Rezultati izbora izazvali su pravi politički zemljotres. — The election results caused a real political earthquake.

This is the usual word in Serbia; potres also means an earthquake in Serbian and is the usual term in Croatian. Potres mozga means concussion.