10.2.2 Rock Falls and Debris Falls
Rock fall refers to quantities of rock falling freely from a cliff face. A rockfall is a fragment of rock (a block) detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down a slope by bouncing and flying along ballistic trajectories or by rolling on talus or debris slopes(figure 3 & 4). It is the natural downward motion of a detached block or series of blocks with a small volume involving free falling, bouncing, rolling, and sliding. Rock falls occur when a piece of rock on a steep slope becomes dislodged and falls down the slope. Debris falls are similar, except they involve a mixture of soil, regolith, and rocks. A rock fall may involve a single rock, or a mass of rocks, and the falling rocks can dislodge other rocks as they collide with the cliff.
Figure 3: Rock material may breaks from an outcrop and falls due to gravity
Figure 4: Damage of rock and vechicals due to rock fall