Mass Wasting Overview and Types

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Questions and Answers

What primarily causes mass wasting in mountainous areas?

Excessive vegetation cover

Low levels of soil moisture

Stable weather patterns

Increased slope steepness (correct)

What is a characteristic of slumps in mass wasting?

They occur on flat surfaces only.

They involve the rapid flow of water and debris.

They involve coherent rock materials sliding along a curved surface. (correct)

They are triggered exclusively by volcanic activity.

How does excessive rainfall affect the stability of a mountain slope?

It causes soil particles to break apart and lose cohesion. (correct)

It makes the vegetation thrive.

It strengthens the bond between soil particles.

It has no significant impact.

Which of the following is NOT a cause of mass wasting?

Decreased slope steepness Signup and view all the answers

What happens to a mountain slope that has reduced vegetation cover?

It is more prone to mass wasting. Signup and view all the answers

What is the nature of the movement in mass wasting events?

Movement is generally downward due to gravity. Signup and view all the answers

What would likely occur if a mountain slope experiences an earthquake?

Detachment of mountain sections due to shaking. Signup and view all the answers

Which statement about the relationship between mass wasting and water is accurate?

Excess water can decrease soil stability and induce mass wasting. Signup and view all the answers

What characterizes a slump in mass wasting events?

A block rotates around an axis while sliding down. Signup and view all the answers

How does a rockslide differ from a slump?

A rockslide moves in a more uniform direction down a slope. Signup and view all the answers

What is a primary characteristic of a debris flow?

It can travel at speeds of 100 miles per hour or greater. Signup and view all the answers

What best describes the movement of an earthflow?

It often moves at a very slow rate, typically a few inches per year. Signup and view all the answers

Which of the following human activities can contribute to slumps?

Road construction that cuts away slope bases. Signup and view all the answers

What is an important component of debris flow that contributes to its destructive nature?

It is a mixture of water, mud, and various debris. Signup and view all the answers

What type of material is predominantly found in an earthflow?

Fine-grained particles such as clay and silt. Signup and view all the answers

Study Notes

Mass Wasting Overview

Mass wasting is the downward movement of rock, soil, and debris due to gravity.
Various factors contribute to mass wasting, including steep slopes, excessive water, and vegetation loss.
Natural forces and human activities can trigger mass wasting events.

Types of Mass Wasting

Slumps

Slumps involve the sliding of coherent rock materials along a curved surface.
It’s a rotational slide where a section of the slope rotates around an axis.
Slumps can occur as single units or in groups and form due to erosion at the base of the slope (e.g., by water or waves).
Human activities, such as road construction, can also trigger slumps.

Rockslides

Rockslides are the sliding of rock material along a pre-existing plane.
Unlike slumps, rockslides move in a more uniform direction.
They often result in piles of rock at the base of a slope.

Debris Flows

Debris flows are the movement of water-laden loose material (mud, sand, soil, rock, debris) down a slope.
They can reach high speeds, up to over 100 miles per hour.
These flows often carry debris, including trees, bridges, and buildings, posing significant danger.

Earthflows

Earthflows involve the flow of fine-grained material (clay, silt, pyroclastic material) that combine with moisture.
The speed varies significantly, from extremely slow (inches per year) to moderate speeds.
Earthflows often form a distinctive hourglass shape.
Typically develop at the lower end of a slope or at the base of slumps.

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Description

Explore the phenomena of mass wasting, including the processes of slumps, rockslides, and debris flows. This quiz covers the factors that influence these geological events, their mechanics, and the impacts of both natural and human activities on mass wasting. Test your knowledge about how gravity affects earth materials in various environments.