Mass movements, erosion, and deposition

Correct answer: A. Balance between driving force and resisting force

A slope may fail when driving force exceeds resisting force. In exams understand slope stability through force balance.

Correct answer: B. Because water can reduce its friction and shear strength

Wet clay can create a slippery surface on a slope. In exams link clay layers and water with slope failure.

Correct answer: C. Reduced basal support and increased pore-water pressure

Toe erosion removes support and rainfall saturates the slope. In exams focus on combined effects of multiple causes.

Correct answer: D. It is a rapid mixed flow of debris over a large area

A debris avalanche is a fast and spreading mass movement. In exams use speed and spread as identification clues.

Correct answer: A. Increased slope instability

Added load above and reduced support below increase failure risk. In exams study loading and undercutting together.

Correct answer: B. Tilted walls and bent trees

Soil creep is slow so small tilting signs are useful evidence. In exams remember field signs of slow movement.

Correct answer: C. Ignoring drainage on the cut slope

Poor drainage increases water pressure and weakens a slope. In exams treat drainage as a key control with road cutting.

Correct answer: D. Nearly planar or layered weak plane

Translational sliding occurs along a relatively planar weak surface. In exams distinguish it from slump.

Correct answer: A. Abrasion cuts the bed while attrition wears particles against each other

In abrasion load rubs the bed and in attrition particles rub each other. In exams identify the target of the action.

Correct answer: B. Capacity means total load and competence means largest particle

Capacity is total sediment load and competence is ability to move the largest particle. Do not reverse these terms in exams.

Correct answer: C. Hard rock lies above soft rock

Soft rock erodes below and the hard cap rock collapses. Link unequal rock resistance with waterfalls in exams.

Correct answer: D. River terraces

Renewed vertical cutting may leave old floodplains as higher terraces. In exams treat terraces as evidence of rejuvenation.

Correct answer: A. Outer bank erosion and inner bank deposition

Curving flow increases erosion on the outer bank and deposition inside. Understand meanders through velocity differences in exams.

Correct answer: B. Pebbles rotating in eddies and abrading the bed

Pebbles rotating in eddies cut rounded holes into the bed. Link potholes with local river abrasion in exams.

Correct answer: C. Load exceeds the river carrying capacity

When load exceeds capacity the river deposits excess sediment. In exams treat overload as a sign of deposition.

Correct answer: D. In sealing the ends of the cut-off meander

The river cuts the meander neck and deposition seals the old loop. Remember both erosion and deposition in oxbow lake formation.

Correct answer: A. Coarser particles deposit near the channel and finer particles farther away

As floodwater spreads beyond the bank heavier particles settle quickly. Remember levees with flood deposition in exams.

Correct answer: B. Strong waves and low river sediment

Strong waves remove sediment and low sediment supply reduces delta growth. Understand deltas through energy and sediment balance.

Correct answer: C. Gradient and carrying capacity

As a stream exits mountains gradient falls and coarse sediment is deposited. Write gradient change as the cause of alluvial fans in exams.

Correct answer: D. Water spreads over sparse vegetation and hard surfaces

In arid regions sudden rain can flow broadly over the surface. Do not ignore the role of water in desert erosion.

Correct answer: A. Fine particles are removed leaving stony pavement

Deflation removes fine sediment and leaves larger particles on the surface. Link desert pavement with deflation in exams.

Correct answer: B. Wind abrasion and erosion

Yardangs may form by wind erosion of rocks with different resistance. Treat them as aeolian erosional landforms in exams.

Correct answer: C. They generally point downwind

Barchan horns usually extend in the direction of prevailing wind. Use the horns to identify wind direction in exams.

Correct answer: D. Loess is fine dust and dunes are mainly sand

Loess is fine wind dust while dunes are built mainly from sand grains. In exams identify the difference by particle size.

Correct answer: A. It is a rock abraded and polished by wind-blown sand

A ventifact is shaped by abrasion from wind-blown sand. Treat it as a clear sign of wind abrasion in exams.