Mass Movement Lab (GEOG 1113L) Exam 2026 Questions and
Answers 100% GSU
1. What is the primary driving force behind all mass movement processes?
A. Solar radiation
B. Wind erosion
C. Tectonic uplift
D. Gravity
Answer: D
Rationale: Gravity is the fundamental force that pulls material downslope, acting as the
primary driver for all mass movement.
2. The steepest angle at which unconsolidated material remains stable is known
as the:
A. Slope gradient
B. Shear plane
C. Angle of repose
D. Critical dip
Answer: C
Rationale: The angle of repose is the maximum angle at which a pile of loose material, like
sand or gravel, can remain stable without sliding.
3. Which of the following materials typically has the highest angle of repose?
A. Fine, dry sand
B. Large, angular rocks
C. Rounded pebbles
D. Wet, saturated silt
Answer: B
,Rationale: Angular and larger particles create more friction and interlocking, allowing for
a steeper stable slope compared to rounded or fine particles.
4. How does the addition of a small amount of water affect the stability of dry
sand?
A. It decreases stability by adding weight.
B. It increases stability through surface tension.
C. It has no effect on stability.
D. It causes immediate liquefaction.
Answer: B
Rationale: A small amount of water creates surface tension that acts like a weak glue,
increasing the cohesion and stability of the sand grains.
5. Excessive water saturation triggers mass movement primarily by:
A. Increasing pore water pressure and reducing friction.
B. Increasing the angle of repose.
C. Decreasing the weight of the slope material.
D. Freezing the soil particles together.
Answer: A
Rationale: Saturation fills pore spaces, increasing pressure which pushes grains apart and
reduces the internal friction (shear strength) of the material.
6. Which type of mass movement is characterized by the slowest rate of
downslope travel?
A. Creep
B. Debris flow
C. Rockfall
D. Slump
Answer: A
, Rationale: Creep is the extremely slow, gradual downslope movement of soil and regolith,
often measured in millimeters or centimeters per year.
7. A curved, rotational slide along a concave-upward surface is specifically called
a:
A. Slump
B. Rockslide
C. Mudflow
D. Creep
Answer: A
Rationale: A slump involves the movement of material as a coherent block along a curved
(rotational) failure surface.
8. What is the most common visible indicator of soil creep on a hillside?
A. Large boulders at the base of the cliff
B. A vertical scarp at the top of the slope
C. A fan-shaped deposit of mud
D. Curved tree trunks and tilted fence posts
Answer: D
Rationale: Because creep affects the upper layers of soil slowly, trees and man-made
structures like fences tilt or curve as the ground moves beneath them.
9. In the context of slope stability, ‘shear strength’ refers to:
A. The internal resistance of a material to sliding.
B. The component of gravity acting parallel to the slope.
C. The total weight of the overlying rock.
D. The velocity at which a landslide moves.
Answer: A
Rationale: Shear strength is the sum of friction and cohesion that holds material in place
against the force of gravity.
Answers 100% GSU
1. What is the primary driving force behind all mass movement processes?
A. Solar radiation
B. Wind erosion
C. Tectonic uplift
D. Gravity
Answer: D
Rationale: Gravity is the fundamental force that pulls material downslope, acting as the
primary driver for all mass movement.
2. The steepest angle at which unconsolidated material remains stable is known
as the:
A. Slope gradient
B. Shear plane
C. Angle of repose
D. Critical dip
Answer: C
Rationale: The angle of repose is the maximum angle at which a pile of loose material, like
sand or gravel, can remain stable without sliding.
3. Which of the following materials typically has the highest angle of repose?
A. Fine, dry sand
B. Large, angular rocks
C. Rounded pebbles
D. Wet, saturated silt
Answer: B
,Rationale: Angular and larger particles create more friction and interlocking, allowing for
a steeper stable slope compared to rounded or fine particles.
4. How does the addition of a small amount of water affect the stability of dry
sand?
A. It decreases stability by adding weight.
B. It increases stability through surface tension.
C. It has no effect on stability.
D. It causes immediate liquefaction.
Answer: B
Rationale: A small amount of water creates surface tension that acts like a weak glue,
increasing the cohesion and stability of the sand grains.
5. Excessive water saturation triggers mass movement primarily by:
A. Increasing pore water pressure and reducing friction.
B. Increasing the angle of repose.
C. Decreasing the weight of the slope material.
D. Freezing the soil particles together.
Answer: A
Rationale: Saturation fills pore spaces, increasing pressure which pushes grains apart and
reduces the internal friction (shear strength) of the material.
6. Which type of mass movement is characterized by the slowest rate of
downslope travel?
A. Creep
B. Debris flow
C. Rockfall
D. Slump
Answer: A
, Rationale: Creep is the extremely slow, gradual downslope movement of soil and regolith,
often measured in millimeters or centimeters per year.
7. A curved, rotational slide along a concave-upward surface is specifically called
a:
A. Slump
B. Rockslide
C. Mudflow
D. Creep
Answer: A
Rationale: A slump involves the movement of material as a coherent block along a curved
(rotational) failure surface.
8. What is the most common visible indicator of soil creep on a hillside?
A. Large boulders at the base of the cliff
B. A vertical scarp at the top of the slope
C. A fan-shaped deposit of mud
D. Curved tree trunks and tilted fence posts
Answer: D
Rationale: Because creep affects the upper layers of soil slowly, trees and man-made
structures like fences tilt or curve as the ground moves beneath them.
9. In the context of slope stability, ‘shear strength’ refers to:
A. The internal resistance of a material to sliding.
B. The component of gravity acting parallel to the slope.
C. The total weight of the overlying rock.
D. The velocity at which a landslide moves.
Answer: A
Rationale: Shear strength is the sum of friction and cohesion that holds material in place
against the force of gravity.
