Heyuan earthquake epicenter depth of 13 kilometers is the source of the earthquake to the surface of the earth is the meaning of 13 kilometers

Seismic waves originated in the place, called the source of the earthquake. Vertical projection of the source on the ground, the ground from the source of the nearest point is called the epicenter. It is the earliest part to receive vibrations. The depth from the epicenter to the source (the distance from the source to the earth's surface) is called the depth of the epicenter. Usually the depth of the epicenter is less than 60 kilometers called shallow earthquakes, the depth of 60-300 kilometers called medium-source earthquakes, the depth of more than 300 kilometers called deep earthquakes.