Faults are defined as the planar discontinuities on the rocks of earth's crust. These are the lines along which one block goes up and the other goes down. There occurs relative displacement of crustal rocks.
These fault lines are often shown in the topographic maps. They are highlighted by the dashed lines when they are present below the surface. And if they are present on the surface of the land, then they are often represented by the solid line.
The lithospheric plates move relative to each other during earthquakes.
