What happens to cause earthquakes at plate boundaries?

Hey!

So imagine the crust is made out of different plates. These plates aren't regularly shaped or similar in size. They are varied.

An earthquake is commonly created when rocks underground (or the plate in general) breaks suddenly along a fault line (this is just where two different plates meet).

The release of [movement] energy causes seismic waves (the chain effect of movement in the ground) which makes the ground shake (this is what we feel). An earthquake won't usually happen is the boundaries were smooth...so commonly occurs on all the different types of boundary!

I HOPE THIS HELPED!