Arrange the following mass movements in increasing order of velocity. (i) Rock fall (ii) Earth flow (iii) Debris flow (iii) Earth creep
Choose the correct answer from the options given below:

Correct option is B

The correct answer is (b) D, B, C, A. The increasing order of velocity for the listed mass movements is:
1. (D) Earth creep:
· The slowest type of mass movement, occurring at a rate of a few millimeters to centimeters per year. It involves gradual downhill movement of soil or rock.
2. (B) Earth flow:
· A moderate-speed flow of fine-grained materials, typically occurring after heavy rainfall. The velocity can range from millimeters per day to meters per day.
3. (C) Debris flow:
· A fast-moving flow of a mixture of water, soil, and debris. Velocities can range from meters per hour to tens of meters per second, depending on the slope and material.
4. (A) Rock fall:
· The fastest type of mass movement, involving the free fall of rock fragments down steep slopes. Velocities can reach several meters per second.
Information Booster 1. Earth Creep:
· Slowest movement due to soil expansion and contraction from moisture changes or freeze-thaw cycles.
2. Earth Flow:
· Typically occurs on gentle to moderate slopes with clay-rich soils that become saturated.
3. Debris Flow:
· Occurs in steep terrains and can be highly destructive, often triggered by heavy rainfall or volcanic eruptions.
4. Rock Fall:
· Common in steep, rocky cliffs and mountains, especially after weathering or seismic activity.
Additional Knowledge · Mass Movements: Geomorphological processes where materials move downslope due to gravity.
· Factors Influencing Velocity:
· Slope Gradient
· Material Type
· Moisture Content