Q. Consider the following statements regarding Mass Movements:
1. Mass movements are aided by gravity and no geomorphic agent like running water, glaciers, wind, waves and currents participate in the process of mass movements.
2. Mass movements do not come under erosion.
Which of the above given statements is/are correct?

[A] 1 only

[B] 2 only

[C] Both 1 and 2

[D] Neither 1 nor 2

Answer: C
Notes:

Mass movements transfer the mass of rock debris down the slopes under the direct influence of gravity.  

  • That means, air, water or ice doesn’t carry debris with them from place to place but on the other hand the debris may carry with it air, water or ice.  
  • The movements of mass may range from slow to rapid, affecting shallow to deep columns of materials and include creep, flow, slide and fall. Gravity exerts its force on all matter, both bedrock and the products of weathering.  
  • So, weathering is not a pre-requisite for mass movement though it aids mass movements. Mass movements are very active over weathered slopes rather than over un-weathered materials.  
  • Mass movements are aided by gravity and no geomorphic agent like running water, glaciers, wind, waves and currents participate in the process of mass movements.  
  • That means mass movements do not come under erosion though there is a shift (aided by gravity) of materials from one place to another.  
  • Materials over the slopes have their own resistance to disturbing forces and will yield only when force is greater than the shearing resistance of the materials.  
  • Weak unconsolidated materials, thinly bedded rocks, faults, steeply dipping beds, vertical cliffs or steep slopes, abundant precipitation and torrential rains and scarcity of vegetation etc., favor mass movements. 

Source: NCERT – XI Fundamentals of Physical Geography