What is an earthquake?
An earthquke is the shaking and trembling result of continental
plates moving,
the plates creat big and little earthquakes that cause damage to buildings
and other structures around the world.
Waves.
Types of waves that are underground are P waves and S waves, primary and secondary.
P waves move side to side and compress and expand earth and buildings.
S waves go side to side as well as up and down,S waves shake structures violently.