Mass movements, erosion, and deposition

Mass movement is the downslope movement of material due to gravity. Exam tip: distinguish it from river transport.

Gravity pulls material down a slope. Exam tip: remember gravity as the basic cause of mass movement.

Soil creep is a very slow type of mass movement. Exam tip: connect very slow movement with creep.

In a landslide slope material moves downward suddenly. Exam tip: link sudden movement with landslide.

On steep slopes the effect of gravity is stronger. Exam tip: connect mountain slopes with landslides.

Erosion means agents like water wind and ice wear away and remove surface material. Exam tip: link erosion with removal of material.

Running water cuts rocks and also deposits material. Exam tip: connect rivers with both erosion and deposition.

When river speed decreases it starts depositing heavier material. Exam tip: link low velocity with deposition.

The direct answer is B: deposition means the accumulation of transported material at a place. Erosion removes sediment, transport moves it, and deposition occurs when the transporting agent loses enough energy to drop it. For example, a river may carry sand and then leave it on a bank when its speed decreases. Option A describes removal, which is erosion, not deposition. Option B correctly describes material collecting or settling in one location. Option C is unrelated to surface-material movement; Earth’s rotation is a planetary motion. Option D describes evaporation, the change of liquid water into vapour, not the settling of sediment. A useful sequence is: weathering breaks, erosion removes, transport carries, deposition drops. Memory cue: deposition means deposit or जमा होना.

In soil erosion, water, wind, or other agents mainly carry away the fertile upper layer of soil. This topsoil contains more humus and plant nutrients, so its loss reduces agricultural productivity. Groundwater is not the surface layer removed during erosion. Exam tip: remember soil erosion as the loss of fertile topsoil.

Wind erodes by removing loose particles in dry areas. Exam tip: remember the role of wind in sandy regions.

A glacier moves as heavy ice and grinds rocks. Exam tip: remember glaciers as erosion agents in cold regions.

Coastal erosion is the wearing away and removal of material from a shore. Sea waves strike cliffs, beaches, and other coastal surfaces, and their repeated force can break, loosen, and carry away rock or sediment. Water pressure, moving sediment, and wave impact may work together, so the coastline can gradually retreat or develop features such as notches and cliffs.

The wording describes waves cutting the coast, which is erosion rather than deposition. Deposition happens when transported material is laid down, while forest formation, snowfall, and soil creep are different processes. A useful distinction is that a wave removing or wearing coastal material causes coastal erosion; a wave dropping sand in a sheltered place contributes to coastal deposition. Hence option A is the correct choice.

Roots bind soil and help stabilize slopes. Exam tip: connect vegetation removal with slope instability.

The direct answer is B: heavy rainfall can saturate soil and make it heavier, weaker, and more likely to slide downhill. Step by step, rain enters the spaces between soil particles; the soil holds more water and gains weight; water can reduce friction and weaken the contact between soil and rock; gravity then pulls the unstable mass down the slope. Option A is wrong because heavy rain generally wets soil rather than making it dry. Option B is correct because saturation and increased weight can reduce slope stability. Option C is wrong because rainfall does not stop gravity; gravity remains the force pulling material downward. Option D is wrong because rain does not automatically flatten a slope. A landslide may also depend on slope angle, vegetation loss, earthquakes, and weak rock, but saturation is the key link in this question. Memory cue: more water, more weight, less stability.

In plains river speed decreases and fine sediments settle. Exam tip: connect fluvial deposition with fertile plains.

Water speed is higher on the outer bank causing erosion. Exam tip: outer bank erosion and inner bank deposition.

Direct answer: Option A, deposition. Water in a river does not move at the same speed everywhere around a bend. On the outer bank, the current is generally faster and erosion is stronger. On the inner bank, the water is generally slower, so it has less ability to carry sand, silt and gravel. The transported material settles there, producing deposition and often a point bar or gentle inner-bank buildup. Option A is correct because low velocity encourages settling. Option B is wrong because an earthquake is a tectonic event, not the normal result of slow flow on an inner bend. Option C is wrong because lava flow comes from volcanic activity, not an ordinary river bend. Option D is wrong because a cyclone is a large atmospheric storm, not a depositional process specific to the inner bank. A small qualification is that local flow conditions can vary, but the general school-level rule is inner bank deposition and outer bank erosion. Memory cue: inner bend is slower and builds; outer bend is faster and cuts.

Erosion removes material and deposition places it elsewhere. Exam tip: connect both with landform change.

Loose soil and a steep slope make mass movement easier. Exam tip: check both slope and looseness.

The direct answer is A: rock falling directly from a steep slope is called a rock fall. It is a rapid type of mass movement in which individual rock pieces or blocks detach and move mainly downward through the air under gravity. Step by step: a steep slope or cliff provides a high position; weathering, cracks, or vibration loosens a block; gravity overcomes its support; the block falls to the foot of the slope. Option A is correct. Option B, soil formation, is a slow process in which weathered material develops into soil, not a sudden fall. Option C, rain shadow, is a dry area on the sheltered side of a mountain and is a climate term. Option D, ocean current, is the movement of seawater and does not describe falling rock. Do not confuse rock fall with a slide: a fall leaves the slope and drops freely or nearly freely. Exam cue: steep cliff plus falling blocks equals rock fall.

Mass movement is directly gravity based while erosion uses external agents. Exam tip: distinguish by the operating agent.

In desert regions, wind carries sand particles and deposits them where its speed decreases. This deposition forms sand dunes. A waterfall is mainly associated with river erosion, while a glacial valley is formed by glacial erosion. Exam tip: remember that sand dunes are the major depositional landforms made by wind in deserts.

The direct answer is A: transporting sand by wind is related to wind action. Wind is moving air, and in dry, open regions it can pick up, roll, bounce or carry loose sand particles. This is part of aeolian erosion and transportation. The reasoning is: sand must be loose and exposed; moving air applies force; sufficiently strong wind lifts or pushes the grains; the grains travel and may later be deposited as dunes or sand sheets. Option A is correct because it directly names the agent responsible for the transport. Option B is wrong because a river flood transports sediment through flowing water, not through wind; it can move sand, but that would be fluvial action. Option C is wrong because sea waves can move beach sand, but the question specifically says that wind carries sand from one place to another, and “sea waves only” is too limited and is not the named process. Option D is wrong because seismic activity means earthquakes and related ground movement; it does not normally transport loose sand over distance. The exam cue is: “sand in dry open land plus moving air equals wind action or aeolian transport.”

A faster river with more water can carry more material. Exam tip: link velocity and discharge with carrying capacity.