The earthquake that hit the Tohoku region of Japan on March 11, 2011, had a magnitude of 9.0 and killed over 15000 people.
An earthquake can last for just a few short seconds or go on for several long minutes.
Many earthquakes happen on the ocean floor. Big ocean waves can form after a quake resulting in a tsunami.
The shaking of the ground is not what kills most victims of earthquakes. The main killers in earthquakes are falling buildings, fires, landslides, avalanches and tsunamis.