The epicenter of an earthquake is the point on the Earth’s surface directly above the hypocenter (or focus), which is the location within the Earth where the earthquake’s seismic energy is released or where the fault slip occurs. In simpler terms:
- The hypocenter (focus) is the point underground where the earthquake originates, typically within the Earth’s crust.
- The epicenter is the point on the Earth’s surface that is directly above the hypocenter.
When an earthquake occurs, seismic waves radiate outward from the hypocenter in all directions and reach the Earth’s surface. The point on the surface where these waves are first detected and where the ground motion is the strongest is designated as the epicenter. It is the epicenter that is commonly used to describe the location of an earthquake, as it is the point most relevant to the impact on human communities and structures.