After the earthquake came a fire, but the Lord was not in the fire. And after the fire came a sound of sheer silence. It was after the silence that a still small voice came to Elijah. A historical earthquake is mentioned in passing in Amos and in Zechariah. Obviously, Biblical writers were fascinated by earthquakes, and referred to them often to make their point.
Earthquakes threaten our assumptions about the stability of life.
We like to think of earth as rock solid, but sometimes the earth moves. We expect the ground to be firm. We want our buildings tied to the bedrock because our foundations need to tie to something that won't move. We are easily lured into thinking the same about our lives. We expect stability.