Earthquakes cause a lot of damage, I will try to go through some of the short-term effects earthquakes have on the world. The effects of the ground shaking by earthquakes usually leads to the destruction of structures such as buildings, bridges and dams. This means that people still in buildings, on roads or under bridges can be seriously injured or killed. They could be killed by structures collapsing on them, glass shattering and hitting people, fires resulting from the earthquake and many other ways that are caused by earthquakes. Earthquakes also trigger landslides, which can also injure and kill people as well as block rivers and cause them to flood surrounding towns and cities. Earthquakes that take place under the ocean can sometimes cause Tsunamis or tidal waves. Tsunamis are giant waves of water which travel very fast. They are known for destroying entire populations and cities on the coast.
This is a picture of a coastal town after the destruction that came with a tsunami caused by an under water earthquake: