Epicenter
The point on the surface directly above where an earthquake's rupture began.
The epicenter is the location on the Earth's surface directly above the hypocenter, the underground point where the fault rupture started. It is the dot you see on every earthquake map, including the USGS pages this tracker links to.
The epicenter is not necessarily where the worst shaking occurs. A long fault can rupture for tens or hundreds of kilometers away from the epicenter, and local soil conditions can concentrate damage far from that point. It marks the start of the rupture, not the whole story of where the ground moved.