Fault Line

noun

The line you can sometimes see on the ground where a fault is — the boundary between two pieces of crust that can move against each other. Some fault lines show as cracks or cliffs; others run hidden underground.

Geotechnical Engineering — Cracker
Go Deeper For parents & teachers
The surface expression of a fault — where the fault plane intersects the ground. Many major fault lines are mapped along topographic features (cliffs, offset rivers, linear valleys) that record their long-term motion. Others are buried beneath sediment or ice and are known only from earthquake epicentres and subsurface imaging techniques like seismic reflection.

The Burning Mountain Chapter 5 — The Hidden Road of Fire

"… A gap here, a buried hollow there, an old crack, a damp fault line. Not one road. Many little roads that together became something larger."