An earthquake is caused by the tectonic plates when one gets on top of the other that is when the earthquake comes in. It changes the surface of the earth by causing the ground to move up when one tectonic is on top of the other. The damage it does is pretty serious sometimes it will depend on on how bad is it like 4-9 those are pretty bad.
It is important people are ready for earthquakes because if there's a earth quake and from the rector scale is nine and they cant get out of there house they would be ready because they have food and flash lite's and water and way more.
Most earth quakes happen in the fault lines (border of tectonic plates)like the San Andre's fault some times here in Colorado, Denver we have earthquakes and we don't even know.
Tsunamis are like the sister to earthquakes they are caused by earthquakes when there's an earthquake under water which creates a huge wave which some times goes around the world then finally it hits land and we got a tsunami.So basically earthquakes and tsunamis are related.what are volcanoes you ask volcanoes are you ask?volcanoes are melted magma as a start but over the years it drys off and turns into rock which starts growing and turns into a volcano and soon it will erupt like this volcano that is erupting this volcano is called mount Fuji. The way a volcano is detirmend is when there's an earth quake and we have a crack inside the crater that's that's when the smoke comes out.