earthquake

A sudden release of energy in the earth's crust that produces seismic waves — the ground itself moving, sometimes gently enough to rattle a window, sometimes violently enough to level a city. Earthquakes originate at a point called the focus, typically along a fault where accumulated tectonic stress exceeds the strength of the rock. The point on the surface directly above is the epicenter. The word is plain — earth plus quake — and the plainness is appropriate. Nothing about the experience is metaphorical. The earth quakes.