15.6 How do mass movements sculpt the landscape?

Fig 15.31
Mass movements are "the" primary agents of regolith movement in mountains. Downcutting by streams steepens valleys, and periodic slides, falls, and flows occur.
A study in NZ points this out by comparing activity based on photos across 60 years—7000 mass movements in that time span lowering the entire 5000 km2 an average of 5 mm/yr or ~30 cm overall.