What are seismic waves?

During an earthquake, earth shakes and waves are produced on the surface of earth

These waves are called seismic waves

Focus -The point of origin of the earthquake deep inside the crust is called the seismic focus. The focus is often deep below the surface of earth.

Epicentre - The epicenter is the point on the earth's surface vertically above the focus where a seismic waves begins on the surface of the earth