How do conservative plate boundaries cause earthquakes?

-Tectonic plates (which can be either continental or oceanic) slide past each other either in opposite directions or in the same direction but at different speeds-This causes friction between the plates to build up and create tensions and stresses between the plates where they catch against one another-These tensions are released suddenly and cause seismic waves to spread out from the focus of the earthquake-The point on land above the focus is called the epicentre of the earthquake-An example of this is the San Andreas Fault line in Southern California where the Pacific plate is moving in the opposite direction to the North American plate causing approximately 10,000 very small earthquakes a year with only about 20 being above magnitude 4.