graben

/ˈɡrɑːbən/
noun
  1. A block of the Earth's crust that has dropped down between two faults, forming a valley or depression.
    • A graben can create a flat valley floor surrounded by steep cliffs.
    • Geologists studied the graben to understand the region's earthquake history.
    • The Rhine Valley is a famous graben formed by tectonic activity.
Antonyms