How do rockfalls differ from other landslide movements?

In geology, a rockfall is distinguished from other types of landslides primarily by its movement mechanism. While many landslides involve the displacement of material along discrete shearing surfaces or within a flowing mass, a rockfall is defined by the abrupt, free-fall movement of loosened blocks of solid rock from a steep slope.21

Key differences include:

• Lack of Shearing: Unlike slides, which involve movement along internal slip planes or shearing surfaces, rockfalls occur when material detaches from a steep face and falls freely under the influence of gravity without significant shearing.1
• Movement Dynamics: After the initial free fall, the rock fragments typically land on a surface where they may bounce or roll further downslope.1
• Classification: Landslides are generally categorized by their type of movement—such as slides, flows, spreads, topples, or falls—and the type of material involved. Rockfalls represent the "fall" category, whereas other movements like rockslides involve sliding along a defined plane.12

While large-volume rockfalls can sometimes trap air to facilitate rapid flow—forming rock avalanches—the fundamental distinction remains the initial detachment and free-fall process.1