습곡은 지하 깊은 곳의 압력으로 변성 및 변형 작용으로 습곡 및 단층이 이뤄진 뒤 지각이 풍화·침식되면서 서서히 융기돼 형성됐다고 한다.
It is said that folds are formed by gradual uplift as the earth's crust is weathered and eroded after folds and faults are formed by metamorphism and deformation under the pressure of the deep basement.