Detailed Understanding Society India and Beyond Class 9 Solutions and Class 9 Social Science SST Chapter 2 Shaping of the Earth’s Surface Question Answer NCERT Solutions make it easier to complete textbook exercises.
Class 9 SST Chapter 2 Shaping of the Earth’s Surface Question Answer
Class 9 Shaping of the Earth’s Surface Question Answer
The Big Questions (Page No. 13)
Question 1.
What shapes the Earth’s surface? (Page No. 13)
Answer:
The Earth’s surface is shaped by internal forces such as plate movements, earthquakes, and volcanic eruptions, and external forces such as weathering, erosion, and deposition. These forces continuously create and modify different landforms.
Question 2.
What is plate tectonics? What are the effects of plate movement? (Page No. 13)
Answer:
Plate tectonics is the theory that explains the movement of the Earth’s lithospheric plates. The Earth’s outer solid layer is divided into several large and small plates that float on the semi-molten mantle beneath them. These plates move very slowly, usually a few centimetres each year. Plate movements occur in three main ways: plates may move towards each other, move apart, or slide past one another. When tectonic plates collide, mountain ranges can form. When they move apart, rift valleys and new ocean floors may develop. When plates slide past each other, earthquakes are common. Plate movement is also responsible for volcanic activity and the formation of many important landforms. Therefore, plate tectonics plays a major role in shaping the Earth’s physical features and influencing geological events.
Question 3.
How are landforms formed and how are they classified? (Page No. 13)
Answer:
Internal processes, such as tectonic movements and volcanic activity, and external processes, such as weathering, erosion, and deposition, form landforms. They are broadly classified into mountains, plateaus, and plains.
Question 4.
How are humans and other living beings connected to these landforms? (Page No. 13)
Answer:
Humans and other living beings are closely connected to landforms because they provide shelter, fertile agricultural land, water resources, forests and wildlife habitats, transport routes, and valuable natural resources such as minerals, all of which support life and economic activities.
Question 5.
How do disasters associated with different landforms impact human lives? (Page No. 13)
Answer:
Disasters associated with different landforms, such as earthquakes, landslides, avalanches, Glacial Lake Outburst Floods (GLOFs), and dust storms, impact human lives by causing loss of life and property, damaging houses, roads, bridges, and crops, disrupting transport and communication, affecting livelihoods, and forcing people to leave their homes.
Class 9 Shaping of the Earth’s Surface Question Answer
InText Questions
Question 1.
Pick any two plates from the map above and complete the table given below. (Page No. 16)
Answer:
Two plates from the map above are
| Name of the Plate | Continents | Ocean |
| Indo-Australian Plate | Asia, Australia | Indian Ocean |
| North American Plate | North America | Atlantic Ocean, Arctic Ocean |
Question 2.
Examine the plate map with the earthquake and volcano map. What correlation do you observe? (Page No. 16)
Answer:
The plate map and the earthquake and volcano map show that most earthquakes and volcanoes occur along tectonic plate boundaries. This indicates that the movement and interaction of tectonic plates are responsible for these natural events.
Question 3.
Observe the map showing the distribution of earthquakes and volcanoes. Can you identify which continents and countries are located around the Ring of Fire with the help of an atlas or a globe? (Page No. 17)
Answer:
The Ring of Fire surrounds the Pacific Ocean and includes parts of the continents Asia, North America, South America, and Australia (Oceania). Countries located around it include Japan, Indonesia, the Philippines, New Zealand, Russia, the United States, Canada, Mexico, Peru, and Chile. These regions experience frequent earthquakes and volcanic eruptions because they lie along active tectonic plate boundaries.
Question 4.
Look carefully at this photograph and answer the following questions. (Page No. 18)
(i) What do you think caused this situation?
(ii) What could that grey powder be?
(iii) What does it tell us about the Earth’s internal forces?
Answer:
(i) This situation was caused by a volcanic eruption that covered the area with ash.
(ii) The grey powder is volcanic ash released during the volcanic eruption.
(iii) It tells us that the Earth has powerful internal forces that can cause volcanic eruptions and bring magma, ash, and gases to the Earth’s surface.
Question 5.
Observe the photographs and also note the types of erosion. How are farmers affected by erosion due to water and wind? (Page No. 21)
Answer:
Farmers are affected by both water erosion and wind erosion because
- These processes remove the fertile topsoil needed for farming.
- Water erosion washes away the fertile topsoil, damages crops, forms gullies, and reduces soil fertility, making the land less productive.
- Wind erosion blows away the loose topsoil, covers fields with sand and dust, and decreases the soil’s ability to retain water and nutrients.
Question 6.
Have you heard about the Sundarbans delta? Try to explore its uniqueness and find out why it is popular with tourists. (Page No. 25)
Answer:
The Sundarbans Delta is unique because it is the largest river delta in the world, formed by the Ganga, Brahmaputra, and Meghna rivers, and is covered with dense mangrove forests. It is popular with tourists because it is home to the Royal Bengal Tiger, diverse wildlife, beautiful waterways, and offers activities such as boat safaris, bird watching, and nature tourism.
Question 7.
A devastating flood struck the Chamoli district in Uttarakhand in February 2021, in which many people and livestock lost their lives. There was severe damage to buildings, roads, bridges, and hydro projects, and connectivity to villages was adversely affected. Can you find out the reasons that led to the sudden and unexpected flood? (Page No. 29)
Answer:
The landforms around my school/residence include open fields, small mounds, and a nearby stream. These features appear to have been shaped mainly by running water. The stream has gradually eroded the soil in some places and deposited sediments in others, creating slightly raised and low-lying areas. If there are flat agricultural fields in the area, they may have been formed by the deposition of fertile soil carried by rivers over a long period. In some dry and sandy areas, wind may also play a role by moving and depositing fine soil particles. Therefore, based on observation, running water is the most important agent responsible for shaping the landforms around my locality, while wind may have contributed to minor changes in some places.
Question 8.
Observe the landforms around your school or residence and try to identify which agent may have created them. (Page No. 32)
Answer:
The sudden flood in Chamoli, Uttarakhand, occurred because
- A large rock and ice mass broke off from a mountain.
- It triggered an avalanche and released huge amounts of water.
- The flood rushed through river valleys, destroying bridges, roads, hydro projects, and villages.
- Climate change and rapid glacier melting increased the risk of such disasters.
Question 9.
Complete the exercises given at the end of each type of disaster with the help of newspapers, atlases, and books. Make a list of disaster-prone areas from India and the world and enlist mitigation measures quoting recent examples. (Page No. 32)
Answer:
The following table lists some major disaster-prone areas in India and the world, along with recent examples and important mitigation measures to reduce their impact.
| Disaster | Disaster-prone Areas | Recent Example | Mitigation Measures |
| Earthquake | Himalayan region, Gujarat, Japan, Turkey | Turkey-Syria Earthquake (2023) | Earthquake-resistant buildings, early warning systems, mock drills |
| Flood | Assam, Bihar, Uttarakhand, Bangladesh | Assam Floods (2024) | Flood forecasting, embankments, proper drainage, afforestation |
| Landslide | Himachal Pradesh, Uttarakhand, Western Ghats | Himachal Landslides (2023) | Avoid construction on steep slopes, afforestation, slope stabilization |
| Cyclone | Odisha, Andhra Pradesh, West Bengal, Philippines | Cyclone Remal (2024) | Early warning, cyclone shelters, evacuation plans |
| Volcanic Eruption | Indonesia, Japan, Iceland | Volcanic eruption in Iceland (2024) | Hazard mapping, evacuation, monitoring volcanic activity |
| Glacial Lake Outburst Flood (GLOF) | Himalayas (India, Nepal, Bhutan) | Sikkim GLOF (2023) | Monitoring glacial lakes, early warning systems, safer infrastructure |
Shaping of the Earth’s Surface Class 9 Questions and Answers
Questions and Activities (Page No. 37-38)
Question 1.
What are the sources of energy that are required to cause movements associated with the internal forces of the Earth?
Answer:
The movements associated with the internal forces of the Earth are mainly caused by heat energy from the Earth’s interior. These energy sources create convection currents in the mantle, which move the tectonic plates.
Question 2.
Relate various physiographic divisions you have studied in the earlier grades with various endogenic forces responsible for their origin.
Answer:
The major physiographic divisions of the Earth are formed by the following different endogenic (internal) forces.
- Mountains: Formed by folding, faulting, and volcanic activity due to the movement of tectonic plates.
- Plateaus: Formed by volcanic eruptions or the uplift of the Earth’s crust.
- Plains: Mainly formed by deposition of sediments by rivers.
- Rift Valleys: Formed by faulting, when blocks of the Earth’s crust move apart or sink.
Question 3.
Why and where do earthquakes occur frequently? Is it possible to predict earthquakes?
Answer:
Earthquakes occur primarily along plate boundaries, where tectonic plates interact with each other. When plates converge, diverge, or slide past each other, immense pressure and stress build up along fault lines. When this stress is suddenly released, it sends seismic waves through the Earth, causing an earthquake. Earthquakes occur most frequently along convergent boundaries (like the Himalayan region), transform boundaries (like the San Andreas Fault in California), and around the Ring of Fire in the Pacific Ocean.
India is also earthquake-prone, especially in the Himalayan region and the northeastern states, as demonstrated by events like the 2001 Gujarat earthquake. As for prediction, it is currently not possible to accurately predict the exact time, location, and magnitude of an earthquake in advance. Scientists can identify earthquake-prone zones and use seismic instruments to monitor activity, but reliable short-term prediction remains a major scientific challenge. Preparedness and mitigation measures are therefore more important than prediction.
Question 4.
“Plate movements are responsible for the distribution of earthquakes and volcanoes.” Explain.
Answer:
Plate movements are responsible for the distribution of earthquakes and volcanoes because tectonic plates are constantly moving due to convection currents in the mantle. Most earthquakes and volcanoes occur along plate boundaries, where plates collide, move apart, or slide past each other. These movements create stress in the Earth’s crust, causing earthquakes, while rising magma at some plate boundaries leads to volcanic eruptions. Therefore, earthquakes and volcanoes are mainly concentrated along plate boundaries, especially around the Pacific Ring of Fire.
Question 5.
Draw and label a diagram of a meander and a delta.
Answer:
Question 6.
How are deforestation and erosion associated with each other? Explain.
Answer:
Deforestation and erosion are closely associated with each other because the removal of trees leaves the soil exposed. Tree roots hold the soil firmly in place and reduce the impact of rain and wind. When forests are cut down, the loose soil is easily carried away by water and wind, leading to increased soil erosion. This reduces soil fertility, damages agricultural land, and increases the risk of landslides.
Question 7.
Develop a plan to protect the land in your local area from erosion.
Answer:
A plan to protect the land in my local area from erosion should include the following measures.
- Plant more trees and grasses to hold the soil firmly with their roots.
- Construct contour bunds, terraces, and check dams to reduce soil erosion and slow the flow of rainwater.
- Avoid deforestation and promote proper land use.
- Maintain proper drainage systems to prevent waterlogging and soil loss.
- Create awareness among local people about soil and water conservation practices.
Question 8.
Which disasters do you think you might experience in your region? Discuss a mitigation plan in your classroom.
Answer:
The disasters that may occur in my region include earthquakes, floods, landslides (in hilly areas), and dust storms, depending on the local geographical conditions.
Mitigation Plan:
- Spread awareness about disaster preparedness and safety measures.
- Plant more trees and prevent deforestation.
- Maintain proper drainage systems and avoid construction in high-risk areas.
- Prepare emergency kits, identify safe shelters, and conduct regular disaster preparedness drills.
- Follow weather warnings and instructions issued by government authorities.
Question 9.
Prepare a model of landforms created by underground water.
Answer:
A model of landforms created by underground water can be prepared by using cardboard or a shoebox as the base. Create a cave and label the main landforms formed by underground water, such as stalactites, stalagmites, sinkholes (dolines), and underground rivers. Use clay, paper, or thermocol to make the landforms and add labels to each feature. This model will help explain how underground water forms Karst topography through chemical weathering and erosion.
Question 10.
What precautionary measures will you take if you are staying in an earthquake-prone region?
Answer:
If I lived in an earthquake-prone area, I would take the following precautions:
- Stay calm and avoid panic.
- Follow the “Drop, Cover, and Hold” method during an earthquake.
- Stay away from windows, mirrors, and heavy furniture.
- Keep an emergency kit ready.
- Learn evacuation routes and emergency contact numbers.
- Use earthquake-resistant construction whenever possible.
- Switch off gas and electricity after the shaking stops.
- Avoid using lifts during or immediately after an earthquake.
- Move to an open area after the tremors stop.
- Follow instructions issued by disaster management authorities.
Question 11.
Prepare a map showing landform-associated disasters that happened in the current calendar year.
Answer:
Do it yourself.
Question 12.
Create a poster showing landforms that are considered to be sacred or important in your region, and add the folk stories associated with them.
Answer:
Do it yourself.
Question 13.
Document a case of a disaster that hit your region in the past, highlighting its effects on various human activities.
Answer:
Case Study: The 2008 Kosi Flood in Bihar
The Kosi Flood of 2008 was one of the most devastating natural disasters in the history of Bihar. In August 2008, the embankment of the Kosi River broke near Kusaha in Nepal, causing the river to change its course. As a result, floodwaters spread across several districts of north Bihar, including Supaul, Madhepura, Saharsa, Araria, Purnia, and Katihar. Millions of people were affected, and thousands of villages remained underwater for several weeks.
The flood had a severe impact on human life. Many people lost their lives, while thousands of families became homeless. People had to take shelter in relief camps, where they faced shortages of food, clean drinking water, and medical facilities. Schools and colleges were closed for many days, disrupting the education of students. Agriculture suffered the most because standing crops were destroyed. Fertile agricultural land remained covered with sand and silt, making farming difficult for several years. Many farmers lost their only source of income and faced financial hardship.
The flood also caused extensive damage to roads, bridges, railways, electricity supply, and communication networks. Transport services came to a halt, making rescue and relief operations difficult. Local markets and small businesses remained closed, affecting trade and employment. The environment was also affected. Large-scale soil erosion occurred, riverbanks were damaged, and many animals died due to drowning and lack of food. Waterlogging and stagnant water increased the spread of diseases such as diarrhoea, malaria, and dengue.
The government, along with the army and several voluntary organisations, carried out rescue and relief operations by providing food, drinking water, medicines, temporary shelters, and medical assistance. Later, damaged roads, bridges, and houses were gradually rebuilt. The 2008 Kosi Flood highlighted the importance of strong embankments, effective flood forecasting, disaster preparedness, and better river management. It also showed that timely rescue operations and community cooperation are essential for reducing the impact of such disasters.
Question 14.
Translate the given poster on landslides into your native language and display it in your home.
Answer:
Do it yourself.
Question 15.
Divide the class into three groups. Each group will work on one project (water, wind, and glacier). The project should highlight the causes, impact on human life and the environment, and mitigation measures.
Answer:
The class can be divided into three groups, with each group working on one of the following topics
Project 1: Water
- Causes: Heavy rainfall, fast-flowing rivers, floods, and sea waves cause erosion and deposition.
- Impact on Human Life and the Environment: Water erosion removes fertile soil, damages crops, roads, and houses, and changes the shape of river valleys and coastlines.
- Mitigation Measures: Plant trees, build check dams and embankments, practise contour farming, and improve drainage systems.
Project 2: Wind
- Causes: Strong winds in dry and sparsely vegetated areas lift and carry loose soil and sand.
- Impact on Human Life and the Environment: Wind erosion causes dust storms, reduces soil fertility, lowers crop production, and affects human health and transportation.
- Mitigation Measures: Plant trees as windbreaks, prevent deforestation, use cover crops, and develop early warning systems.
Project 3: Glacier
- Causes: The movement of glaciers and rapid melting due to rising temperatures reshape the land and may cause Glacial Lake Outburst Floods (GLOFs).
- Impact on Human Life and the Environment: Glacial erosion forms valleys and moraines, while GLOFs can damage roads, bridges, houses, and agricultural land.
- Mitigation Measures: Monitor glacial lakes, install early warning systems, strengthen natural dams, avoid construction in high-risk areas, and train people for emergency evacuation.