Maharashtra Board Class 9 Geography Chapter 2 Endogenetic Solutions

Endogenetic Movements Class 9 Questions And Answers Maharashtra Board

Class 9 Geography Chapter 2 Endogenetic Movements Questions And Answers Maharashtra Board

Geography Class 9 Chapter 2 Question Answer Maharashtra Board

Question 1. Tick in front of the correct option ✓
(a) On which of the following are slow movements in the earth's interior dependent?
Landforms []
Velocity []
Direction []
Answer: Velocity
In simple words: Slow movements within the Earth's interior are primarily influenced by the velocity of the moving forces. Different velocities lead to different geological outcomes like folding or faulting.

🎯 Exam Tip: Understanding the factors influencing Earth's slow movements is crucial for explaining landform development.

 

Question 1. Tick in front of the correct option ✓
(b) When waves divert from each other, what do they create
Compression []
Tension []
Mountain []
Answer: Tension
In simple words: When geological forces pull rocks apart, creating a stretching effect, it results in tension within the Earth's crust. This process often leads to faulting and the formation of rift valleys.

🎯 Exam Tip: Differentiate between compression and tension in geological movements as they lead to distinct landforms.

 

Question 1. Tick in front of the correct option ✓
(c) For the formation of a rift valley, which of the following processes should occur in the earth's crust?
Compression []
Tension []
Weathering []
Answer: Tension
In simple words: Rift valleys form when tensional forces pull the Earth's crust apart, causing blocks of land to subside between parallel faults. This stretching and breaking of the crust are characteristic of tensional movements.

🎯 Exam Tip: Remember that tensional forces are key to understanding the formation of rift valleys and block mountains.

 

Question 1. Tick in front of the correct option ✓
(d) Which of these is a fold mountain?
The Satpudas [ ]
The Himalayas []
The Western Ghats [ ]
Answer: The Himalayas
In simple words: The Himalayas are an example of fold mountains, formed when two tectonic plates collide, and the immense pressure causes layers of rock to buckle and fold upwards. This process is a classic result of compressional forces.

🎯 Exam Tip: Be able to identify major fold mountain ranges and associate them with compressional plate movements.

 

Question 1. Tick in front of the correct option ✓
(e) The formation of extensive plateaus is a result of which type of movements?
Mountain-building []
Continent-building []
Horizontal []
Answer: Continent-building
In simple words: Extensive plateaus are often formed by epeirogenic or continent-building movements, which involve the large-scale uplift or subsidence of continental masses over long geological periods. These movements create broad, elevated landforms.

🎯 Exam Tip: Distinguish between mountain-building (orogenic) and continent-building (epeirogenic) movements and their respective landforms.

 

Question 2. Give geographical reasons.
(a) Buildings collapsed at the foothills of the Himalayas because of an earthquake. Before collapsing they were moving forward and backward.
Answer:
• The seismic waves can be divided into primary, secondary and surface waves.
• The primary waves are the first ones to reach the surface of the earth after the energy is emitted in the Earth's interior.
• Subjected to a 'P' wave, particles in the rock move in the direction of waves to and fro and therefore, these waves are also called forward-backward waves.
• Thus, during an earthquake, the buildings at the foothills of the Himalayas moved forward and backward as they were first subjected to “P” waves.
In simple words: Buildings at the Himalayan foothills moved back and forth during the earthquake because they were affected by primary (P) waves, which are the fastest seismic waves causing particles to vibrate in the direction of wave propagation.

🎯 Exam Tip: Focus on the characteristics of P-waves and their direct impact on structures during an earthquake.

 

Question 2. Give geographical reasons.
(b) There is a difference in the formation of the Meghalaya Plateau and the Deccan Plateau.
Answer:
1. The Meghalaya plateau is formed due to slow movements (orogenic movements) whereas the Deccan Plateau is formed due to sudden movements (fissure volcano).
2. During the formation of the Meghalaya plateau, a part of the Earth's crust in between two parallel faults was lifted forming a plateau whereas, the Deccan plateau was formed due to molten material coming out with the eruption spreading on both sides of the fissure.
3. Thus, there is a difference in the formation of the Meghalaya plateau and the Deccan plateau.
In simple words: The Meghalaya Plateau resulted from slow uplift and faulting, while the Deccan Plateau was formed by sudden, massive fissure volcanic eruptions that spread vast sheets of lava. These distinct geological processes created their unique characteristics.

🎯 Exam Tip: Clearly distinguish between the causes of formation (slow movements vs. sudden volcanic eruptions) for different plateau types.

 

Question 2. Give geographical reasons.
(c) Most of the volcanoes are found on the plate boundaries.
Answer:
• The plate boundaries are directly related to the areas of volcanoes.
• Most of the volcanoes are located on the plate boundaries.
• The part of the plate boundary which slides under the crust, results in the loss of material. Such boundaries are called plate consuming boundaries.
• In areas where new material (magma) is coming up onto the Earth's crust, they are called plate creating boundaries.
• Both the processes result in earthquakes and volcanoes. Thus, most of the volcanoes are formed in the plate boundaries.
In simple words: Volcanoes are concentrated at plate boundaries because these are zones where tectonic plates either collide (consuming boundaries, leading to subduction and melting) or pull apart (creating boundaries, allowing magma to rise), both processes involving magma moving towards the Earth's surface.

🎯 Exam Tip: Linking volcanic activity directly to plate tectonics, specifically consuming and creating boundaries, is key to scoring.

 

Question 2. Give geographical reasons.
(d) The Barren Island is becoming conical in shape.
Answer:
• Barren island which was considered a dormant volcano has become active since February 2017.
• Mainly dust, smoke and mud are coming out of this eruption along with some lava.
• During eruption, the lava is spread around the mouth of this vent, when it comes out.
• As a result, a cone-shaped mountain starts forming.
Therefore Barren Island is becoming conical in shape.
In simple words: Barren Island is becoming conical because its dormant volcano reactivated, emitting lava, dust, and smoke. As the lava and ejected materials accumulate around the vent, they build up a distinctive cone shape over time.

🎯 Exam Tip: Explain the process of material ejection and accumulation leading to the specific landform (conical shape of a volcano).

 

Question 2. Give geographical reasons.
(e) Volcanic eruptions can cause earthquakes.
Answer:
• Generally, the movements in the Earth's interior occur in the upper layer of the mantle
• Tremendous energy is released by radioactive materials present here.
• This leads to a sudden movement in form of volcanic eruptions where hot solid, liquid and gaseous materials are forcefully thrown out from the mantle of the Earth, onto the surface of the Earth.
• This causes a lot of instability within the crust of the Earth which would also lead to the release of pressure in the form of seismic waves or tremors causing earthquakes.
In simple words: Volcanic eruptions cause earthquakes because the forceful movement of magma and gases within the Earth's crust creates immense pressure and instability. This pressure can fracture rocks and generate seismic waves, leading to ground tremors.

🎯 Exam Tip: Emphasize the connection between magma movement, pressure buildup, and the subsequent release of seismic energy during volcanic activity.

 

Question 3. Identify and name the internal movement.
(a) Tsunamis are generated in coastal areas.
Answer: Sudden Movement
In simple words: Tsunamis are caused by sudden, powerful undersea events like earthquakes or volcanic eruptions, which displace large volumes of ocean water rapidly.

🎯 Exam Tip: Relate tsunamis to sudden geological shifts beneath the ocean, not slow movements.

 

Question 3. Identify and name the internal movement.
(b) The Himalayas are an example of fold mountains.
Answer: Slow movement - Mountain Building Movements.
In simple words: The Himalayas are formed by the slow, continuous collision of tectonic plates, where immense compressional forces over millions of years cause rock layers to fold and uplift.

🎯 Exam Tip: Understand that major mountain ranges like the Himalayas are products of long-term, slow, compressional movements.

 

Question 3. Identify and name the internal movement.
(c) Molten magma is thrown out of the earth's mantle.
Answer: Sudden Movement
In simple words: The expulsion of molten magma from the Earth's mantle is a rapid and forceful event, indicative of sudden internal geological activity like a volcanic eruption.

🎯 Exam Tip: Volcanic eruptions, characterized by magma expulsion, are clear examples of sudden Earth movements.

 

Question 3. Identify and name the internal movement.
(d) Rift valley is formed because of faulting.
Answer: The slow movement - Upward - Downward Movement.
In simple words: Rift valleys form due to the slow, tensional forces within the Earth's crust that cause blocks of land to move vertically (upward or downward) along faults, leading to a subsided linear depression.

🎯 Exam Tip: Note that while faulting is a sudden break, the overall formation of large rift valleys is often a cumulative result of slow, vertical movements.

 

Question 4. Arrange the following statements in chronological order in which an earthquake occurs.
(a) The earth's surface vibrates
Answer: The plates suddenly move.
In simple words: The Earth's surface vibrates as a direct consequence of the sudden, intense movement of tectonic plates, which releases seismic energy.

🎯 Exam Tip: For chronological order, always start with the underlying cause (plate movement) before the visible effects.

 

Question 4. Arrange the following statements in chronological order in which an earthquake occurs.
(b) The plates suddenly move.
Answer: Due to the movements in the mantle compression goes on increasing.
In simple words: Plates suddenly move when the accumulated compression from mantle movements exceeds the strength of the rocks, causing a rapid release of stored energy.

🎯 Exam Tip: Recognize that mantle convection drives plate movement, leading to increasing stress at plate boundaries.

 

Question 4. Arrange the following statements in chronological order in which an earthquake occurs.
(c) Due to the movements in the mantle, compression goes on increasing.
Answer: Along the weak point (faultlines) rocks break apart.
In simple words: As compression increases due to mantle movements, the stress eventually becomes too great, causing rocks to fracture and break along existing weak points, known as faultlines.

🎯 Exam Tip: Connect increasing compression directly to the fracturing of rocks along fault lines as a precursor to energy release.

 

Question 4. Arrange the following statements in chronological order in which an earthquake occurs.
(d) Along the weak points (faultlines) rocks break apart.
Answer: Stored energy is released in the form of seismic waves.
In simple words: When rocks break along faultlines, the immense energy that has been stored due to tectonic stress is suddenly released, propagating through the Earth as seismic waves.

🎯 Exam Tip: The breaking of rocks along faults is the immediate trigger for the release of seismic energy.

 

Question 4. Arrange the following statements in chronological order in which an earthquake occurs.
(e) Stored energy is released in the form of seismic waves.
Answer: The earth's surface vibrates.
In simple words: The release of stored energy as seismic waves causes the ground to shake and vibrate, which is felt as an earthquake on the Earth's surface.

🎯 Exam Tip: The final observed effect of an earthquake is the ground vibration caused by seismic waves reaching the surface.

 

Question 5. Distinguish between
(a) Block Mountain and Fold Mountain
Answer:

Block Mountain	Fold Mountain
(i) When a part of the earth's crust between two parallel faults is lifted a block mountain is formed.	(i) Because of the energy waves and pressure working towards each other, the layers of the soft rocks form folds leading to the formation of fold mountains.
(ii) Block mountains are formed due to tension.	(ii) Fold mountains are formed due to compression.
(iii) e.g. The Black forest mountains of Europe and the Meghalaya Plateau of India.	(iii) e.g. The Himalayas, the Aravalis, the Rockies, the Andes, the Alps

In simple words: Block mountains form from tensional forces that lift or drop blocks of crust along faults, creating steep-sided peaks, while fold mountains result from compressional forces that buckle and fold rock layers upwards.

🎯 Exam Tip: Focus on the types of forces (tension vs. compression) and the resulting structural deformation (block faulting vs. folding) as key differentiating factors.

 

Question 5. Distinguish between
(b) Primary and Secondary Seismic Waves
Answer:

Primary Seismic Waves	Secondary Seismic Waves
(i) Primary waves are the first one to reach the surface of the earth after the energy is emitted in the Earth's interior.	(i) The waves which reach the Earth's surface after the primary waves are called secondary waves.
(ii) Primary waves can travel through solid, liquid and gaseous medium.	(ii) Secondary waves can travel only through only solid medium.
(iii) While travelling through liquid medium, primary waves change their direction.	(iii) Secondary waves get absorbed as they enter the liquid medium.
(iv) The waves move to and fro in the direction of energy transfer.	(iv) These waves move up and down in the direction of energy transfer.

In simple words: Primary (P) waves are faster, arrive first, and can travel through all mediums by compressing and expanding material, while Secondary (S) waves are slower, arrive second, and can only travel through solids by moving material perpendicular to their direction.

🎯 Exam Tip: Remember the key differences: speed, arrival time, type of motion, and mediums of travel for P and S waves.

 

Question 5. Distinguish between
(c) Earthquakes and volcanoes
Answer:

Earthquakes	Volcanoes
(i) Earthquake is the movement of the Earth's crust.	A volcano is an opening in the Earth's crust from which hot solid, liquid and gaseous materials are thrown out from the mantle of.
(ii) Nothing is ejected out during an earthquake.	During a volcanic eruption, ash, water vapor, various types of poisonous and inflammable gases, hot molten magma etc. is ejected from the earth's interior.

In simple words: Earthquakes are sudden ground tremors caused by the movement of Earth's crust without material ejection, whereas volcanoes are openings from which hot molten material, ash, and gases erupt from the Earth's interior.

🎯 Exam Tip: Focus on the fundamental definitions, primary actions (movement vs. eruption), and whether material is ejected or not.

 

Question 6. Answer in brief
(a) Give reasons why an earthquake occurs.
Answer:
• When the movements occur in the interior of the Earth, tremendous tension is created in the Earth's crust.
• When the tension goes beyond limits, the energy is released in the form of waves.
• This results in the trembling of the earth's surface, i.e. an earthquake occurs.
Following are the reasons for the occurrence of an earthquake:
• Moving of the plates
• Colliding of the plates
• Plates sliding one below the other
• Forming of fractures in rock layers, due to tension in the interior of the Earth.
• Occurring of volcanic eruption
In simple words: Earthquakes occur when stress from internal Earth movements (like plate movement, collision, or sliding) builds up in the crust beyond its breaking point. This built-up energy is suddenly released as seismic waves, causing the ground to tremble.

🎯 Exam Tip: List both the general mechanism (tension and energy release) and specific geological activities (plate movements, faulting, volcanism) that cause earthquakes.

 

Question 6. Answer in brief
(b) Which type of movements have led to the formation of the major fold mountains in the world?
Answer:
• Fold mountains are formed due to mountain-building (orogenic) movements.
• Energy is transferred from the interior of the Earth. Because of these energy waves and pressure working towards each other and in horizontal direction, the layers of the soft rocks form folds.
• If the pressure is very high, large scale folds are formed and their complexity increases.
• As a result, the surface of the Earth gets uplifted and fold mountains are formed.
• The Himalayas, the Aravalis, the Rockies, the Andes, the Alps are the major fold mountains of the world.
In simple words: Major fold mountains are formed by orogenic (mountain-building) movements, which involve intense compressional forces caused by the collision of tectonic plates. This pressure folds and uplifts the Earth's crust over long periods.

🎯 Exam Tip: Emphasize "orogenic movements" and "compressional forces" as the primary drivers behind fold mountain formation, and provide examples.

 

Question 6. Answer in brief
(c) How is the magnitude of the earthquake-related to the collapse of houses
Answer:
• Through a seismogram, a graph showing movement of seismic waves (seismograph) can be generated.
• After studying this graph, the magnitude of the earthquake is known.
• The magnitude of the earthquake is measured with the help of a richter scale.
• It is because of the primary waves that the buildings on the Earth's surface move back and forth.
• The buildings on the Earth's surface move up and down because of the secondary waves. These are more destructive than the T' waves leading to collapse of buildings.
In simple words: The magnitude of an earthquake, measured by the Richter scale, determines the intensity of ground shaking. Higher magnitudes result in stronger primary (back-and-forth) and secondary (up-and-down) waves, which can cause severe stress and collapse in buildings.

🎯 Exam Tip: Connect earthquake magnitude to the destructive power of seismic waves (P and S waves) and their specific impacts on buildings.

 

Question 6. Answer in brief
(d) What are the effects of earthquakes on the earth's surface and human life?
Answer:
Following are the effects of earthquakes:
• Cracks/fractures develop on the ground.
• These causes landslides which leads to sliding of rocks.
• Sometimes the groundwater changes its course. For example, wells may get water, or may dry up.
• Some areas get uplifted while some may subside.
• Tsunamis are generated in oceans These waves can cause great loss of life and property in the coastal areas.
• In snow-covered areas, avalanches may occur.
• Buildings collapse and loss of life and property occurs.
• Transportation routes get disrupted.
• The communication system collapses.
In simple words: Earthquakes cause diverse impacts, including ground cracks, landslides, changes in groundwater, uplift or subsidence, tsunamis, and avalanches. They also lead to widespread destruction of buildings, infrastructure, and significant loss of life.

🎯 Exam Tip: Categorize effects into physical changes on the Earth's surface and direct impacts on human life and infrastructure for a comprehensive answer.

 

Question 6. Answer in brief
(e) Explain the types of seismic waves.
Answer:
When the intension is released at the focus, the released energy travels in all directions. This energy comes towards the Earth's surface in the form of waves. The seismic waves can be divided into primary, secondary and surface waves.
(i) Primary or 'P' waves:
• These waves are first to reach the surface of the Earth, after the energy is emitted in the Earth's interior. They travel at a very fast speed from the focus of the earthquake in radial direction.
• The waves moves to and fro, therefore these waves are called forward-backward waves.
• These waves can travel through all the three states - liquid, solid and gaseous.
• While travelling through liquid medium, their direction gets changed. It is because of the primary waves that the buildings on the Earth's surface move back and forth.
(ii) Secondary or 'S' waves :
• The waves which reach the Earth's surface after I the primary waves are called secondary waves. :
• These waves also scatter in all directions from the focus of the earthquake.
• Their velocity is less than 'P' waves.
• The particles lying in the way of these waves j move up and down in the direction of energy transfer.
• These waves can travel only through the solid medium and they get absorbed as they enter the liquid medium.
• The buildings on the Earth's surface move up and down because of these waves. These are more destructive than 'P waves.
(iii) Surface or 'L' waves :
• These waves are generated after the main 'P' and 'S' waves reach the epicenter.
• They travel in the direction of the circumference of the Earth, along the crust and are highly destructive.
In simple words: Seismic waves are energy pulses released during earthquakes, categorized as Primary (P-waves, fast, compressional, travel through all mediums), Secondary (S-waves, slower, shear, travel only through solids), and Surface (L-waves, slowest, most destructive, travel along the Earth's surface).

🎯 Exam Tip: For each wave type, remember its relative speed, arrival order, particle motion, and the types of mediums it can travel through, as well as its destructive potential.

 

Question 6. Answer in brief
(f) Explain the types of volcanoes on the basis of the periodicity of eruption with examples.
Answer:
According to the periodicity of the volcanic eruptions, three types of volcanoes can be identified.
(i) Active Volcanoes -
• If the volcanic eruptions are regular even in the present times, then such volcanoes are called active volcanoes.
• E.g., Mt Fujiyama in Japan and Mt. Stromboli in the Mediterranean Sea.
(ii) Dormant Volcanoes -
• When a volcano has not erupted since long, but may become active suddenly is called a dormant volcano.
• E.g., Mt. Vesuvius in Italy, Mt. Katmai in Alaska and Barren Island, India.
(iii) Extinct volcanoes -
• Those volcanoes which have not erupted in the past since long and are not likely to erupt in the future are called extinct volcanoes.
• E.g., Mr. Kilimanjaro in Tanzania.
In simple words: Volcanoes are classified by eruption frequency: Active volcanoes erupt regularly (e.g., Mt. Fujiyama), Dormant volcanoes have been inactive but could erupt again (e.g., Mt. Vesuvius), and Extinct volcanoes have not erupted for a very long time and are not expected to erupt in the future (e.g., Mt. Kilimanjaro).

🎯 Exam Tip: Define each type of volcano clearly and provide at least one relevant example for each category.

 

Question 7. Show the epicenter, focus and the primary, secondary and surface waves of an earthquake with the help of a neat labeled diagram.
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र पृथ्वी के आंतरिक भाग को दर्शाता है जिसमें ऊर्जा निकलने का 'फोकस' बिंदु है। फोकस से तरंगें (प्राथमिक और द्वितीयक) बाहर की ओर फैलती हैं। 'अधिकेंद्र' पृथ्वी की सतह पर फोकस के ठीक ऊपर स्थित है, जहाँ से 'सतही तरंगें' फैलती हैं।
In simple words: The diagram illustrates an earthquake by showing the focus (origin of energy release), the epicenter (point on the surface directly above the focus), and the propagation of primary, secondary, and surface seismic waves from these points.

🎯 Exam Tip: A well-labeled diagram clearly showing the focus, epicenter, and the different types of seismic waves greatly enhances understanding and scoring.

 

Question 8. Show the following on a given outline map of the world.
(a) Mt. Kilimanjaro
(b) Mid-Atlantic Earthquake zone
(c) Mt. Fuji
(d) Krakatoa
(e) Mt. Vesuvius
Answer:
ℹ️ चित्र व्याख्या (Diagram Explanation): यह विश्व मानचित्र पृथ्वी की प्रमुख टेक्टोनिक प्लेटों को उनके उपभोग और निर्माण सीमाओं के साथ दर्शाता है। इसमें दुनिया भर के महत्वपूर्ण भूकंप क्षेत्रों और विभिन्न ज्वालामुखियों (जैसे माउंट किलिमंजारो, माउंट फ़ूजी, माउंट वेसुवियस, क्राकाटोआ, मध्य-अटलांटिक भूकंप क्षेत्र) के स्थान भी अंकित हैं।
World : Earthquakes and Volcanoes
In simple words: The world map depicts the major tectonic plates, indicating areas where plates converge or diverge, alongside the distribution of earthquake zones and prominent volcanoes like Mt. Kilimanjaro, Mt. Fuji, Krakatoa, and Mt. Vesuvius.

🎯 Exam Tip: Accurately locating key geographical features like volcanoes and earthquake zones on a world map demonstrates strong geographical knowledge.

 

Class 9 Geography Chapter 2 Endogenetic Movements Intext Questions and Answers

Can You Tell?

Read the following news. Observe the photograph and answer the questions.
NEPAL DEVASTATED
Powerful earthquake rocks Nepal, nearly 1500 killed
Kathmandu: 25 Apr (PTI)
A powerful earthquake measuring 7.9 on Richter scale struck Nepal today, as nearly 900 people were killed and over 1000 people were injured in the disaster.
The quake and a series of serious aftershocks delivered a severe blow to Nepal. The tremors were also felt across vast stretches of east and northeast India. It was also felt in China, Bhutan and as far as Pakistan and Bangladesh. The quakes also jolted parts of North and Northeast India.
The earthquake with epicentre at Lamjung, around 80 kilometers northwest of Kathmandu, had its impact in several cities in Bihar, West Bengal and Uttar Pradesh.
The initial report said the tremor measured 7.9-magnitude.
It said the quake hit at 11:40 am local time at a shallow depth of 11 km. There were 17 major aftershocks measuring over 5 in the next two and half hours," said an officer of the National Seismological Centre.
Another aftershock measuring 6.6 hit within 80 minutes of the quake. This is the largest earthquake in Nepal after 80 years. India has sent rescue teams immediately
2 BIG TREMORS
7.9 Richter Scale
11.40 am
6.6 Richter scale
12.19 pm
Epicenter :
Lamjung
(Nepal)
No of Dead: India 53, Tibet 12, Bangladesh 2
• Focus 11 km deep
• 17 more shocks after 2 big tremors
• Duration ranging from 30 sec to 2 min
• India, Bangladesh and Pakistan also experience tremors
• 22 States in India feel the tremors

 

Question 1. What caused large-scale casualties?
Answer: Calamity of earthquake led to large scale casualties.
In simple words: The powerful earthquake was the primary cause of the extensive loss of life and injuries, referred to as large-scale casualties.

🎯 Exam Tip: Directly identify the earthquake as the cause of casualties based on the provided news snippet.

 

Question 2. What was the magnitude of the earthquake?
Answer: The magnitude of the earthquake was 7.9 Richter scale.
In simple words: The earthquake's strength was measured at 7.9 on the Richter scale, indicating its high intensity.

🎯 Exam Tip: Accurately extract numerical data like magnitude from news articles or given text.

 

Question 3. Which country was the most affected because of this earthquake?
Answer: Nepal was most affected because of this earthquake.
In simple words: Based on the news, Nepal suffered the most significant impact from the earthquake.

🎯 Exam Tip: Identify the primary geographic focus of the disaster description to determine the most affected country.

 

Question 4. Where was the epicentre of the earthquake?
Answer: Lamjung in Nepal was the epicentre of the earthquake.
In simple words: The earthquake's epicenter, the point on the Earth's surface directly above the origin, was located in Lamjung, Nepal.

🎯 Exam Tip: Locate specific geographical details, such as the epicenter, directly from the source text.

 

Question 5. Which are the other affected areas?
Answer: Bihar, West Bengal and Uttar Pradesh in India as well as China, Bhutan, Pakistan and Bangladesh were affected by earthquake.
In simple words: Besides Nepal, the earthquake also impacted parts of India (Bihar, West Bengal, Uttar Pradesh), China, Bhutan, Pakistan, and Bangladesh.

🎯 Exam Tip: List all mentioned geographical locations that experienced the tremors or effects of the earthquake.

 

Question 6. At what depth was the focus located?
Answer: The focus of the earthquake was located at the depth of 11 km.
In simple words: The earthquake originated at a relatively shallow depth of 11 kilometers below the Earth's surface.

🎯 Exam Tip: Extract precise numerical data for the focus depth as provided in the source material.

 

Question 7. What kind of damage is seen because of the earthquake?
Answer: Nearly 1500 people were killed and over 1000 people were injured in the disaster.
In simple words: The earthquake caused significant human casualties, with approximately 1500 fatalities and over 1000 injuries.

🎯 Exam Tip: Summarize the immediate human impact (deaths and injuries) as the primary damage mentioned.

 

Question 8. According to you, what could be the reason behind the earthquake?
Answer: The sudden release of energy from the interior of the earth leads to earthquakes.
In simple words: Earthquakes occur due to the abrupt release of immense stored energy within the Earth's interior, typically caused by the movement and friction of tectonic plates.

🎯 Exam Tip: Frame your answer around the fundamental geological cause: sudden energy release from Earth's interior.

 

Question 9. Have you ever experienced a similar earthquake? Discuss.
Answer: Answers may vary.
In simple words: This question prompts personal reflection on earthquake experiences, so responses will differ based on individual encounters.

🎯 Exam Tip: For open-ended personal questions, acknowledge that answers will be subjective and varied.

Class 9 Geography Chapter 2 Endogenetic Movements Additional Important Questions And Answers

Complete The Statements Choosing The Correct Option From The Bracket:

Question 1. Richter scale is a unit of measuring the magnitude of a/an
(a) volcano
(b) creation of plate
(c) earthquake
(d) earth movement
Answer: (c) earthquake
In simple words: The Richter scale is specifically designed and used to quantify the magnitude, or energy released, by an earthquake.

🎯 Exam Tip: Remember the specific purpose of the Richter scale in measuring earthquake magnitude.

 

Question 2. There are in all major plates on the Earth.
(a) five
(b) seven
(c) nine
(d) four
Answer: (b) seven
In simple words: Geologists generally identify seven primary tectonic plates that make up the Earth's lithosphere.

🎯 Exam Tip: Be aware of the number of major tectonic plates to answer such factual questions.

 

Question 3. Large scale and sudden release of energy in the interior of the Earth gives rise to Earth movements.
(a) slow
(b) sudden
(c) internal
(d) external
Answer: (b) sudden
In simple words: The rapid and significant release of energy from within the Earth results in sudden and often dramatic Earth movements, such as earthquakes.

🎯 Exam Tip: Link "large scale and sudden release of energy" directly to "sudden" Earth movements.

 

Question 4. Earthquakes occur due to the movement of
(a) plates
(b) earth
(c) oceans
(d) land
Answer: (a) plates
In simple words: Earthquakes primarily result from the movement and interaction of the Earth's tectonic plates along their boundaries.

🎯 Exam Tip: The core cause of most earthquakes is the shifting and interaction of tectonic plates.

 

Question 5. Earthquake is measured with the help of an instrument called a
(a) seismogram
In simple words: A seismogram is the record produced by a seismograph, which is the instrument that detects and measures earthquakes.

🎯 Exam Tip: Understand that the seismograph is the instrument, and the seismogram is the recording it produces.

 

Question 6. If lava is released through a vent, it is called a vent volcano.
(a) fissure
(b) central
(c) upper
(d) below
Answer: (b) central
In simple words: When magma erupts from a single, pipe-like opening in the Earth's crust, it is known as a central vent volcano.

🎯 Exam Tip: Identifying different types of volcanic eruptions and their characteristics is crucial for scoring well in geography questions related to internal movements.

 

Question 7. Kilimanjaro is a volcano.
(a) central type
(b) fissure type
(c) extinct type
(d) dormant type
Answer: (a) central type
In simple words: Mount Kilimanjaro is an example of a central type volcano, which means its lava erupts from a single, concentrated vent.

🎯 Exam Tip: Knowing specific examples of each type of volcano helps illustrate understanding and earns full marks.

 

Question 8. A tremendous amount of energy is given out by the radioactive elements in the
(a) crust
(b) core
(c) mantle
(d) sial
Answer: (c) mantle
In simple words: The Earth's mantle contains radioactive elements whose decay releases significant energy, driving many internal geological processes.

🎯 Exam Tip: Understanding the Earth's internal structure and the energy sources within it is fundamental to explaining geological phenomena.

 

Question 9. The movements that give rise to mountains are called movements.
(a) epiorogenic
(b) orogenic
(c) slow
(d) sudden
Answer: (b) orogenic
In simple words: Orogenic movements are the slow, internal Earth movements responsible for the formation of large mountain ranges through folding and faulting.

🎯 Exam Tip: Distinguishing between different types of internal movements (e.g., orogenic vs. epeirogenic) and their resulting landforms is important.

 

Question 10. When a portion of the crust between two parallel faults is raised up, it is called a mountain.
(a) block
(b) fold
(c) residual
(d) ancient
Answer: (a) block
In simple words: A block mountain forms when a section of the Earth's crust is uplifted between two faults.

🎯 Exam Tip: Clearly defining landforms based on their formation processes (e.g., block vs. fold mountains) is key to accurate answers.

 

Question 11. The area between two adjoining faults subsides, such area of subsidence is called
(a) rift valley
(b) block mountain
(c) fold mountain
(d) faulting
Answer: (a) rift valley
In simple words: A rift valley is a lowland region that forms when a block of Earth's crust drops down between two parallel faults.

🎯 Exam Tip: Knowing the geological terms for subsided and uplifted areas between faults is crucial for describing tectonic landforms.

 

Question 12. Black Forest Mountain in Europe is a mountain.
(a) fold
(b) residual
(c) block
(d) ancient
Answer: (c) block
In simple words: The Black Forest mountains are a classic example of block mountains, formed by tectonic uplift between fault lines.

🎯 Exam Tip: Remembering key examples for different landforms helps reinforce your understanding and provides concrete evidence in answers.

 

Question 13. The movements that give rise to continents are
(a) orogenic
(c) fold
(b) epeirogenic
(d) fault
Answer: (b) epeirogenic
In simple words: Epeirogenic movements are broad, slow, upward or downward movements of the Earth's crust that lead to the formation of continents and plateaus.

🎯 Exam Tip: Differentiate between orogenic (mountain-building) and epeirogenic (continent-building) movements, as they represent distinct scales of crustal deformation.

Endogenetic Movements Class 9 Geography Chapter 2 Tick in Front of the Correct Option.

 

Question 1. Which of these is a block mountain?
(a) Black forest mountain
(b) Alps
(c) Andes
Answer: (a) Black forest mountain
In simple words: The Black Forest in Germany is a prime example of a block mountain, formed when large blocks of crust are uplifted along faults.

🎯 Exam Tip: Always associate specific geographical features with their correct classification to show comprehensive knowledge.

 

Question 2. Which type of volcano has eruptions regularly even during present times?
(a) Dormant
(b) Extinct
(c) Active
Answer: (c) Active
In simple words: An active volcano is characterized by frequent or continuous eruptions in recent times, indicating ongoing geological activity.

🎯 Exam Tip: Understanding the classification of volcanoes (active, dormant, extinct) based on their eruption frequency is a fundamental concept.

Give One Word For Each Of The Following:

 

Question 1. A volcano, where lava reaches the surface through a vent or a pipe.
Answer: Central Vent Volcano
In simple words: This describes a central type volcano where magma rises and erupts through a single, main conduit.

🎯 Exam Tip: Concise one-word answers demonstrate precise understanding of geographical terms.

 

Question 2. An instrument, which is used for recording earthquakes.
Answer: Seismogram
In simple words: A seismograph is the instrument, and a seismogram is the record it produces, showing ground motion during an earthquake.

🎯 Exam Tip: Be precise with terminology; distinguish between the instrument (seismograph) and the record (seismogram).

 

Question 3. The surface position immediately above the origin of an earthquake.
Answer: Epicenter
In simple words: The epicenter is the point on the Earth's surface directly above where an earthquake originates, often experiencing the most intense shaking.

🎯 Exam Tip: Clearly distinguish between the focus (origin below surface) and the epicenter (point on surface). This is a common point of confusion.

 

Question 4. An example of a volcanic plateau.
Answer: Deccan Plateau.
In simple words: The Deccan Plateau in India was formed by extensive fissure-type volcanic eruptions, where lava flowed over a vast area.

🎯 Exam Tip: Providing a well-known example like the Deccan Plateau strengthens your answer regarding volcanic landforms.

 

Question 5. An example of Conical volcanic mountains.
Answer: Mt. Kilimanjaro
In simple words: Mount Kilimanjaro is an iconic conical volcano, a type of mountain formed by accumulated lava and ash from repeated eruptions.

🎯 Exam Tip: Specific examples demonstrate a practical application of theoretical knowledge about geological features.

Class 9 Geography Chapter 2 Endogenetic Movements Questions And Answers Answer in One Sentence Each.

 

Question 1. What are Endogenetic processes?
Answer: Endogenetic processes are processes that originate internally in the Earth's surface. E.g. earthquakes, volcanoes, continent building, mountain building etc.
In simple words: Endogenetic processes are geological activities like earthquakes and volcanic eruptions that originate from within the Earth and shape its surface.

🎯 Exam Tip: Providing clear examples along with the definition enhances the quality of your answer.

 

Question 2. What is a Richter scale?
Answer: It is a scale for expressing the magnitude of an earthquake.
In simple words: The Richter scale is a numerical scale used to measure the strength or magnitude of an earthquake based on the amplitude of seismic waves.

🎯 Exam Tip: Remember that the Richter scale measures magnitude (energy released) not intensity (effect on surface).

 

Question 3. What is a Focus or Hypocentre?
Answer: The point below the Earth's surface where energy is released during an earthquake is called the focus of the earthquake.
In simple words: The focus, also called the hypocenter, is the exact underground point where an earthquake originates, releasing seismic energy.

🎯 Exam Tip: Using both terms "focus" and "hypocenter" correctly demonstrates a thorough understanding of earthquake terminology.

 

Question 4. What are Primary Waves?
Answer: The earthquake waves that reach the surface of the Earth first, immediately after the energy is released in the interior of the Earth, are called Primary waves.
In simple words: Primary waves (P-waves) are the fastest seismic waves that travel through solids, liquids, and gases, causing particles to move back and forth in the direction of wave propagation.

🎯 Exam Tip: Focus on the key characteristics of P-waves: speed, type of movement, and mediums they can travel through.

 

Question 5. What are Secondary Waves?
Answer: The earthquake waves reporting at the surface after the primary waves are called the secondary waves.
In simple words: Secondary waves (S-waves) are slower than P-waves and can only travel through solid mediums, causing particles to move perpendicular to the wave's direction.

🎯 Exam Tip: Differentiate S-waves from P-waves by their speed and the types of material they can propagate through.

 

Question 6. What are Surface Waves?
Answer: Primary and secondary waves affect the surface on reaching it. As a result a new set of waves gets generated at the surface. These waves are called surface waves.
In simple words: Surface waves are seismic waves that travel along the Earth's surface, generated by the interaction of P and S waves with the surface, and are responsible for most earthquake damage.

🎯 Exam Tip: Recognize that surface waves are the most destructive type of seismic waves due to their movement along the Earth's surface.

 

Question 7. What are Plates?
Answer: The parts of varying sizes of the Earth's crust floating on the upper portion of the mantle are called plates.
In simple words: Plates are large, rigid sections of the Earth's lithosphere that move slowly over the softer, semi-fluid asthenosphere, causing geological activity.

🎯 Exam Tip: Emphasize that plates are composed of crust and a part of the upper mantle, and their movement drives plate tectonics.

 

Question 8. What do you mean by an Epicentre?
Answer: The point located on the surface of the Earth nearest to the focus is called the epicenter of the earthquake.
In simple words: The epicenter is the point on the Earth's surface directly above the earthquake's origin (focus), where seismic waves first arrive.

🎯 Exam Tip: Clarity in defining "epicenter" as a surface point is crucial, distinguishing it from the deeper "focus."

 

Question 9. Explain Orogenic Movements
Answer: The slow movements in the interior of the Earth that give rise to mountains are called orogenic movements (mountain building movements).
In simple words: Orogenic movements are the long-term, slow internal forces that fold and fault the Earth's crust, leading to the formation of large mountain ranges.

🎯 Exam Tip: Use the term "mountain building movements" interchangeably with "orogenic movements" to show versatility in geographical vocabulary.

 

Question 10. What is Folding?
Answer: As energy moves through the interior of the Earth, soft rocks are subjected to pressure leading to creation of folds called folding.
In simple words: Folding is the process where layers of rock bend and deform under compressional forces, typically forming wavelike structures.

🎯 Exam Tip: Explain that folding occurs primarily in soft or ductile rocks under intense pressure, leading to structures like anticlines and synclines.

 

Question 11. Define Fault.
Answer: The fracture line created in a rock due to the energy waves moving away from each other is called a fault.
In simple words: A fault is a fracture or zone of fractures in rock along which there has been displacement, caused by tensional or compressional forces.

🎯 Exam Tip: Specify that faults involve displacement, distinguishing them from simple cracks or fractures without movement.

 

Question 12. What is a Block Mountain?
Answer: A raised portion of the crust between two parallel faults is called a block mountain.
In simple words: A block mountain forms when a section of the Earth's crust is uplifted or remains high relative to adjacent areas that have subsided along parallel faults.

🎯 Exam Tip: Emphasize the role of tensional forces and parallel faults in the creation of block mountains.

 

Question 13. What is a Rift valley?
Answer: The area of subsidence between two adjoining faults is called a rift valley.
In simple words: A rift valley is a linear lowland created when a block of land subsides between two parallel normal faults, often associated with tectonic plates pulling apart.

🎯 Exam Tip: Mentioning the association of rift valleys with divergent plate boundaries and tensional forces adds depth to the explanation.

 

Question 14. Explain Epeirogenic Movements.
Answer: The Earth's slow movements that give rise to continents and extensive plateaus are called epeirogenic movements.
In simple words: Epeirogenic movements are large-scale, slow vertical movements of the Earth's crust that lead to the uplift or subsidence of continental landmasses and plateaus.

🎯 Exam Tip: Highlight that epeirogenic movements affect vast areas and typically result in elevation changes rather than intense folding or faulting.

 

Question 15. Explain the process of Volcanic Eruption.
Answer: A process in which hot solid, liquid and gaseous materials are thrown out from the mantle of the earth onto the surface of the earth, is called volcanic eruption.
In simple words: Volcanic eruption is the process where molten rock (magma), ash, and gases escape from the Earth's interior through a vent or fissure to the surface.

🎯 Exam Tip: Mention the different forms of material ejected (solid, liquid, gaseous) to provide a complete description of a volcanic eruption.

Identify And Name The Internal Movements.

 

Question 1. Dust, smoke and mud with some lava coming out of Barren Island.
Answer: Sudden Movement
In simple words: The eruption of materials from Barren Island signifies sudden internal movements related to volcanic activity.

🎯 Exam Tip: Volcanic eruptions are clear indicators of sudden endogenetic movements due to the rapid release of energy and material.

Distinguish Between:

 

Question 1. Seismic Focus and Epicentre
Answer:

Seismic Focus	Epicenter
(i) The point below the surface where energy is released during an earthquake is called the seismic focus of the earthquake.	(i) The place on the surface which is directly above the focus and closest to it is called the epicenter.
(ii) From the seismic focus, an energy wave radiates in all directions.	(ii) Seismic waves reach the epicenter first and foremost and so its intensity is the maximum at this point.

In simple words: The seismic focus is the underground origin point of an earthquake, while the epicenter is the point on the Earth's surface directly above it, where shaking is often strongest.

🎯 Exam Tip: A clear, comparative table is highly effective for "Distinguish between" questions, ensuring all key differences are highlighted.

 

Question 2. Central Type Volcano and Fissure Type Volcano
Answer:

Central Type Volcano	Fissure Type Volcano
(i) Lava is released through a pipe-like vent, hence it is called central type volcano.	(i) Lava is released through a number of fissures or cracks, hence it is called fissure type volcano.
(ii) The ejected material gets settled near the mouth of the central vent, giving rise to conical hills.	(ii) The ejected material spreads on either side of the fissures and forms volcanic plateaus.
(iii) e.g. Mt. Fujiyama of Japan, Mt. Kilimanjaro in Tanzania.	(iii) e.g. the Deccan plateau of India

In simple words: Central type volcanoes erupt from a single vent, forming conical mountains, whereas fissure type volcanoes erupt from long cracks, creating extensive plateaus.

🎯 Exam Tip: Including distinct examples for each type of volcano reinforces the differences and demonstrates comprehensive knowledge.

 

Question 3. Orogenic Movements and Epeirogenic Movements
Answer:

Orogenic Movements	Epeirogemic Movements
(i) The movements that give rise to mountains are called Orogenic Movements.	(i) The movements that give rise to continents are called Epeirogenic Movements.
(ii) They lead to the formation of Fold mountains, Block mountains and Rift valleys.	(ii) They lead to the formation of continents and extensive plateaus.

In simple words: Orogenic movements are responsible for mountain formation through folding and faulting, while epeirogenic movements cause broad uplift or subsidence that forms continents and plateaus.

🎯 Exam Tip: Clearly differentiating the scale and resulting landforms of these two types of movements is crucial for a strong answer.

 

Question 4. Slow Internal Movements and Sudden Internal Movements
Answer:

Slow Internal Movements	Sudden Internal Movements
(i) The movements in the interior of the earth that are caused by continuous and slow release of energy are called slow internal movements	(i) The movements in the interior of the earth that are caused by the sudden release of energy on a large scale are called sudden internal movements.
(ii) Slow internal movements give rise to mountains and continents.	(ii) Sudden internal movements lead to earthquakes and volcanic eruptions.

In simple words: Slow internal movements gradually build mountains and continents, while sudden internal movements release large amounts of energy quickly, causing earthquakes and volcanic eruptions.

🎯 Exam Tip: Focus on the rate of energy release and the resulting geographical features to effectively distinguish between slow and sudden internal movements.

Make Friends With Maps!

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र विश्व के प्रमुख विवर्तनिक प्लेटों, भूकंपीय क्षेत्रों और ज्वालामुखियों को दर्शाता है। इसमें दिखाया गया है कि कैसे पृथ्वी की सतह बड़ी प्लेटों में विभाजित है, और इन प्लेटों की सीमाओं पर भूकंप और ज्वालामुखी जैसी प्रमुख भूगर्भीय गतिविधियाँ केंद्रित होती हैं। चित्र विभिन्न महासागरीय और महाद्वीपीय प्लेटों, जैसे प्रशांत प्लेट, यूरेशियाई प्लेट, अफ्रीकी प्लेट, और उत्तरी अमेरिकी प्लेट, और उनके किनारों पर स्थित ज्वालामुखी और भूकंपीय हॉटस्पॉट को स्पष्ट करता है।

Answer The Following Questions:

 

Question 1. Examine the plate boundaries in the given map and write the names of the plates.
Answer: North American Plate, South American Plate, Indo-Australian Plate, African Plate, Eurasian Plate, Pacific Plate, Antarctic Plate, Arabian Plate, Nazca Plate, Cocos Plate, Caribbean Plate, Scotia Plate, Arabian Plate and Somali Plate.
In simple words: The map displays the major tectonic plates of the world, including large continental and oceanic plates, whose interactions drive global geological activity.

🎯 Exam Tip: Familiarize yourself with the names and locations of the major tectonic plates, as this knowledge is fundamental to understanding plate tectonics.

 

Question 2. On which side of the continents of North and South America are the earthquake-prone zones located? Which mountains are located there?
Answer: The earthquake-prone zone is located on the western side of North and South America. Rockies and Andes mountain ranges are located there.
In simple words: Earthquake-prone zones in North and South America are predominantly on their western coasts, coinciding with the location of the Rocky and Andes mountains, which are formed by plate collisions.

🎯 Exam Tip: Connecting the location of earthquake zones with major mountain ranges demonstrates an understanding of plate boundary dynamics.

 

Question 3. In which mountainous zone in Asia does the earthquake-prone zone lie?
Answer: The Himalayan mountainous zone of Asia is an earthquake-prone zone.
In simple words: In Asia, the earthquake-prone zone is situated within the Himalayan mountainous region, a result of the ongoing collision between the Indian and Eurasian plates.

🎯 Exam Tip: The Himalayas are a classic example of a collision plate boundary, explaining the high seismic activity in that region.

 

Question 4. In which region are the volcanoes concentrated in Africa? What could be the reason?
Answer: Volcanoes are concentrated in the eastern part of Africa along the Rift Valley region as this region is located on plate boundaries.
In simple words: Volcanoes in Africa are primarily concentrated along the East African Rift Valley because this area is a divergent plate boundary where the continent is slowly splitting apart.

🎯 Exam Tip: Understanding that volcanic activity often occurs at plate boundaries, especially divergent ones, helps explain their geographical distribution.

 

Question 5. Correlate earthquake regions, distribution of volcanoes and plate boundaries.
Answer: Plate boundaries are directly related to areas of earthquakes and volcanoes. Most of the volcanoes are located on the plate boundaries. Similarly, the earthquake zones are also seen in the border areas.
In simple words: Earthquake regions and volcanic distributions largely coincide with plate boundaries because these are zones of intense tectonic activity where plates interact, causing stress, friction, and magma movement.

🎯 Exam Tip: This question requires synthesising knowledge about plate tectonics; emphasize that plate boundaries are the primary drivers of both earthquakes and volcanic eruptions.

Give Geographical Reasons:

 

Question 1. The secondary earthquake waves are very destructive.
Answer:
• Due to secondary earthquake waves, the grains in the rocks move up and down, that is, perpendicular to the direction of the movement of the waves.
• Therefore, secondary waves are very destructive.
In simple words: Secondary (S) waves are destructive because they cause rock particles to move perpendicular to the wave's direction of travel, creating significant shearing and shaking.

🎯 Exam Tip: When explaining destructiveness, focus on the type of motion (shear/perpendicular) that S-waves impart, which causes structural damage.

Answer In Brief:

 

Question 1. Explain the types of volcanoes on the basis of their type of eruption, with examples.
Answer: On the basis of the type of eruption, volcanoes can be divided into two types.
(i) Central-type or conical volcano:
• During eruption, the molten magma comes out through a pipe-like vent from inside the Earth's surface. The lava spreads around the mouth of this vent, when it comes out.
• Asa result, cone-shaped mountains start forming and conical volcanic mountains are formed.
• Mt. Fujiyama in Japan and Mt. Kilimanjaro in Tanzania are examples of central-type volcanoes and conical mountains.
(ii) Fissure-type volcano:
• During eruption, when the magma comes out not from a single vent, but from many cracks (fissures), it is called fissure-type volcanic eruption.
• The molten material coming out with the eruption spreads on both the sides of the fissure. -
• As a result, volcanic plateaus are formed.
• The Deccan Plateau of India has also been formed due to such a type of volcanic eruption.
In simple words: Volcanoes erupt either from a central pipe (central-type), building conical mountains like Mt. Fujiyama, or from long cracks (fissure-type), spreading lava widely to form plateaus like the Deccan Plateau.

🎯 Exam Tip: Clearly define each type of eruption, describe the resulting landform, and provide specific geographical examples for full marks.

 

Question 2. Describe the changes that take place on the surface of the Earth, due to the movements taking place in the interior of the Earth.
Answer: The changes taking place on the surface of the Earth, due to the internal movements of the Earth are as follows:
1. The soft rocks are subjected to pressure due to the energy released in the interior of the Earth. This leads to the development of folds.
2. If the pressure is very high, large scale folds are formed, and their complexity increases. As a result, the surface of the Earth gets uplifted and fold mountains are formed.
3. When the energy waves move away from each other, tension in the rock is developed. In hard rocks, the tension leads to faulting, when a portion between two parallel faults is raised up, block mountains are created.
4. Sometimes, when the portion between two parallel faults subsides, a rift valley is created.
5. Sometimes, an extensive portion is raised to form a continent or an extensive plateau.
In simple words: Internal Earth movements cause folding in soft rocks to form fold mountains, faulting in hard rocks to create block mountains and rift valleys, and broad uplift to form continents or plateaus.

🎯 Exam Tip: Structure your answer by linking specific internal movements (compression, tension, uplift) to the distinct landforms they create on the Earth's surface.

 

Question 3. How are continents and extensive plateaus formed?
Answer:
• The epeirogenic movements are responsible for the formation of continents.
• Slow movements occur towards the centre or from the Earth's centre towards the Earth's crust.
• Because of these movements, a vast part of the Earth's crust is uplifted or gets subsided.
• When the part of the Earth's crust is uplifted above the sea mean level, continents are formed.
• Therefore, these movements are called continent-building movements.
• Extensive plateaus can also be formed because of such movements.
In simple words: Continents and extensive plateaus are formed by epeirogenic movements, which are slow, broad, vertical uplifting of large parts of the Earth's crust.

🎯 Exam Tip: Emphasize "epeirogenic movements" as the primary cause and differentiate them from mountain-building forces.

 

Question 4. What are the effects of volcanoes?
Answer: The following are the effects of volcanoes:
• Loss of life and property.
• Sometimes tsunamis get generated due to volcanic eruptions occurring below ocean floors.
• Dust, smoke, ash, gases, water vapour, etc. remain in the atmosphere for a long time.
• This may create an imbalance in the environment.
• Land may become fertile due to volcanic ash.
• Many minerals are found near the earth's surface because of lava.
• New land is formed due to volcanic eruption or at times, an island may even disappear.
• Lakes are formed at the mouth of the craters of dead volcanoes when rainwater accumulates in them.
In simple words: Volcanoes cause both destructive effects like loss of life, tsunamis, and atmospheric pollution, and constructive effects such as creating fertile land, mineral deposits, and new landforms.

🎯 Exam Tip: For this type of question, provide a balanced answer, including both the negative (destructive) and positive (constructive) effects of volcanic activity.

 

Question 5. Explain the process of the formation of Block mountains.
Answer:
• Because of internal movements, horizontal waves moving away from each other are formed.
• This causes tension on the layers of rocks leading to the formation of fractures in the rocks called as faults.
• Similarly, waves coming towards each other in hard rocks also form faults due to compression.
• When a part of the earth's crust in between two parallel faults is lifted, it looks like a block. Such a landform is called as a Block mountain.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र 'ब्लॉक पर्वत' के निर्माण की प्रक्रिया को दर्शाता है। इसमें दिखाया गया है कि कैसे तनाव (tension) बल के कारण पृथ्वी की ऊपरी परत में दो समानांतर भ्रंश (faults) बन जाते हैं। इन भ्रंशों के बीच का हिस्सा ऊपर उठ जाता है, जिससे एक ब्लॉक जैसी संरचना बनती है जिसे ब्लॉक पर्वत कहते हैं। चित्र भ्रंश रेखाओं और उनके बीच उठे हुए भूभाग को स्पष्ट रूप से चित्रित करता है।
In simple words: Block mountains form when tensional forces cause parallel faults in the Earth's crust, leading to the uplift of the land block between these faults relative to the surrounding areas.

🎯 Exam Tip: Clearly explain the role of tensional forces and parallel faults in creating the characteristic block-like structure of these mountains.

 

Question 6. Explain the process of formation of Rift valley.
Answer:
• When horizontal movements on the earth's surface act in opposite direction, it causes tension on the rocks in the earth's crust.
• When tension increases, fractures develop in the rocks leading to the formation of faults.
• Consequently, rocks on both the ends slide and the continuity in the layers of rocks is not found.
• Sometimes, two fractures develop side-by-side in the earth's crust and land in between the two fractures subsides. This subsided deep part is called the rift valley.
ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र 'रिफ्ट घाटी' के निर्माण की प्रक्रिया को दर्शाता है। इसमें दिखाया गया है कि कैसे तनाव (tension) बलों के कारण पृथ्वी की ऊपरी परत में दो समानांतर भ्रंश (faults) बनते हैं, और इन भ्रंशों के बीच का भूभाग नीचे धंस जाता है। धंसा हुआ यह गहरा हिस्सा एक लंबी, संकरी घाटी का रूप ले लेता है जिसे रिफ्ट घाटी कहते हैं। चित्र भ्रंश रेखाओं और उनके बीच धंसे हुए भूभाग को स्पष्ट रूप से दर्शाता है।
In simple words: A rift valley forms when tensional forces pull the Earth's crust apart, creating two parallel faults, and the land block between these faults subsides to form a long, narrow depression.

🎯 Exam Tip: Emphasize the tensional forces and the subsidence of the central block as key mechanisms in rift valley formation.