What rock is formed at the fault line of an earthquake?

From an earthquake's point of view, there's more than one way to devastate a city. Most earthquakes occur along cracks in the planet's surface called faults. These cracks may be small and localized or can stretch thousands of miles where tectonic plates meet. Usually, the rocks on either side of the fracture are moving past each other too slowly for us to notice, but sometimes stress (pressure) builds up and they'll suddenly slip, making a big move all at once. The effect of that sudden shift depends on the type of fault the movement occurs in.