Final answer:
A landslide is a type of mass movement where material moves along a concave surface, often preserving some of the original surface. Examples include slope failures, rockslides, and debris flows.
Step-by-step explanation:
The mass movement that involves movement along a concave surface with some of the original surface often preserved is called a landslide. A landslide is a type of mass wasting where a significant amount of rock, soil, or debris moves down a slope due to factors like gravity, erosion, or human activities.
One example of a landslide is a slope failure, where the slope of a hill or mountain fails and moves down, often preserving some of the original surface.
Other examples include rockslides, debris flows, lahars, and slumps, all of which involve the movement of material along a concave surface.