Examkin

Question

Difficulty: MediumWeathering and Mass Wasting Processes

Mass movement processes vary significantly in their mechanism and rate of downslope displacement under the influence of gravity. Arrange the following mass wasting processes in sequential order from the slowest rate of movement to the fastest rate of movement.

  1. 1Soil Creep
  2. 2Solifluction
  3. 3Rotational Slump
  4. 4Rockfall

Answer

The correct sequence from slowest to fastest velocity is Soil Creep, followed by Solifluction, Rotational Slump, and Rockfall.
Mass wasting processes are classified by their velocity and movement mechanism. Soil creep is imperceptibly slow (millimeters/year). Solifluction is slow soil flow (centimeters to meters/year). Rotational slump represents moderate speed coherent rotational sliding along a curved rupture surface. Rockfall is the fastest process, featuring airborne free-fall at several meters per second.

Step-by-Step Solution

1
Identify the slowest form of mass wasting.
Soil creep is identified as the slowest process, measuring only millimeters per year.
Creep is driven by freeze-thaw or wetting-drying expansion/contraction cycles operating over extended periods.
2
Identify the slow-to-moderate flow process operating in saturated topsoil.
Solifluction follows soil creep as a slow downslope flow process.
Water saturation reduces friction in saturated regolith over impermeable substrate, causing slow flow measured in centimeters to meters annually.
3
Identify the moderate-speed sliding process.
Rotational slump comes next in velocity.
Slumping occurs along a defined curved slip plane, yielding faster displacement than soil creep or solifluction.
4
Identify the fastest mass movement process.
Rockfall is identified as the fastest mass wasting type.
Rockfall involves direct free-fall under gravity through air without basal friction, resulting in instantaneous, high-velocity movement.

Key Concept

Mass Wasting Rates of Movement
Rate this question

Topics

Weathering and Mass Wasting Processes

More questions from this topic