Seismic energy is a wave phenomenon. From the hypocenter or focus of the earthquake, the seismic waves depart in all directions. There are two types: body ones and surface ones. The former, of little destructive power, travel through the interior of the Earth and produce the preliminary tremors of an earthquake. Body waves are divided into primary and secondary. The surface waves, which are the most destructive, travel across the Earth's surface and appear after the arrival of the primary and secondary waves to the epicenter of the earthquake. Depending on the type of waves, an earthquake can be trepidatory or oscillatory. Depending on the depth of the focus, eathquakes can be superficial, intermediate or deep. This infographic from the Ábaco collection corresponds to the Catastrophes series, to which the following original titles also belong: Tsunamis, Deep Tear, Risk Areas and Measure an Earthquake.