Lesson Notes By Weeks and Term - Senior Secondary 3

TERM – 1^ST TERM

WEEK FIVE

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: MASS MOVEMENT

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Explain the concept of mass movements.
2. Identify types of mass movements
3. Describe the processes involved in the different types of mass movements 
4. Analyse the effects of mass movements on man

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

MASS MOVEMENT

Mass movements refer to the downslope movement of earth materials under the influence of gravity. These movements involve the transfer of soil, rock, and debris from higher elevations to lower elevations and are typically driven by the force of gravity acting on the Earth's surface. Mass movements can occur slowly over long periods or rapidly during events like landslides.

Types of Mass Movements

1. Landslides: Landslide is a mass movement of rock, soil, and debris down a slope, often triggered by factors such as heavy rainfall, earthquakes, volcanic activity, or human activities. Landslides can range from slow, gradual movements to rapid, destructive events, and they can occur on various scales, from small localized occurrences to large, landscape-altering events.
2. Rock avalanche is a more significant and chaotic mass movement involving the rapid descent of a large volume of rock material. Rock avalanches typically occur when a massive amount of rock detaches from a mountain or cliff, often triggered by factors like earthquakes, volcanic activity, or human activities.
3. Soil Creep: Soil creep is a slow, continuous downslope movement of soil and regolith. It is characterized by the gradual displacement of individual soil particles, typically in response to the expansion and contraction caused by temperature changes. While soil creep may be imperceptible over short periods, its cumulative effect can lead to noticeable changes in the landscape over time.
4. Slumps: Slumps are a type of mass movement involving the rapid movement of a mass of rock or soil along a curved slip surface. Unlike slides that move along a flat plane, slumps occur along a concave surface. Slumps are often triggered by saturation of the soil, which reduces its stability. They can result in the tilting or rotation of the affected material, leading to distinct features in the landscape.

Processes involved in the different types of mass movements

The following are processes Involved in different types of Mass Movements:

1. Rockfalls: Individual rocks detach due to weathering or seismic activity, free-falling or bouncing downslope.
2. Rockslides: Blocks of rock move as a unit, often along pre-existing fractures, sliding downslope.
3. Debris Flows: Rapid downslope movement of a mixture of soil, rock, and water, often triggered by heavy rainfall or rapid snowmelt.
4. Rock Avalanches: Swift and chaotic descent of large volumes of rock:* Triggered by factors like earthquakes, volcanic eruptions, or oversteepening of rock slopes.
5. Creep: Slow, continuous downslope movement of soil and regolith:* Expansion and contraction of soil particles due to temperature changes, causing gradual displacement.
6. Slumps: Rapid movement along a curved slip surface:* Often initiated by saturation of soil, causing the overlying material to slide along a curved plane.

Effects of mass movements on man

The following are effects of Mass Movements on Man

1. Rapid mass movements, such as landslides and mudflows, can lead to the loss of human lives and cause extensive damage to infrastructure, homes, and agricultural land.
2. Communities living in areas prone to mass movements may face forced relocation due to the destruction of their homes and the risk of future hazards.
3. Roads, bridges, and other infrastructure may be severely damaged or destroyed, hindering transportation and access to affected areas.
4. Mass movements can have significant economic consequences, including the cost of rebuilding, loss of livelihoods, and disruptions to local economies.
5. Mass movements can lead to environmental degradation, affecting ecosystems, water quality, and biodiversity in the affected areas.
6. Areas affected by mass movements may experience reduced agricultural productivity due to soil erosion, loss of topsoil, and disruption of farming practices.

EVALUATION: 1. What is Mass movement?

2. Mention and discuss the r types of mass movement
3. Discuss 5 processes that takes place in Mass movement that you know.
4. Mention 5 effects of Mass movement on Man.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively