Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1 Lithosphere – I Endogenetic Processes

You can Download Samacheer Kalvi 9th Social Science Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.

Tamilnadu Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1 Lithosphere – I Endogenetic Processes

Lithosphere – I Endogenetic Processes Textual Exercise

I. Choose the correct answer.

Question 1.
The ………….. is the rigid outer layer of the Earth.
(a) core
(b) mantle
(c) Crust
(d) inner core
Answer:
(c) Crust

Question 2.
…………… layer is made up of liquid iron.
(a) Inner core
(b) Outer core
(c) Mantle
(d) Crust
Answer:
(b) Outer core

Question 3.
Magma is found in the ……………
(a) crust
(b) mantle
(c) core
(d) None of the above
Answer:
(b) mantle

Question 4.
Diastrophism is connected to ……………
(a) volcanism
(b) earthquakes
(c) tectonics
(d) fold/fault
Answer:
(c) tectonics

Question 5.
The movement of tectonic plates is induced by ………….. energy.
(a) hydel
(b) thermal
(c) wave
(d) tidal
Answer:
(b) thermal

Question 6.
In the ancient period, Gondwana land moved towards ………….. direction.
(a) north
(b) south
(c) east
(d) west
Answer:
(a) north

Question 7.
Many million years ago, India was a part of the super continent ………….
(a) Gondwana
(b) Laurasia
(c) Panthalasa
(d) Pangea
Answer:
(a) Gondwana

Question 8.
The movement of plates that creates stress and tension in the rocks causing them to stretch and cracks result in ………….
(a) fold
(b) fault
(c) mountain
(d) earthquake
Answer:
(b) fault

Question 9.
……………… refers to a bowl-shaped depression found at the top of the volcano.
(a) crater
(b) vent
(c) chamber
(d) volcanic cone
Answer:
(a) crater

Question 10.
The point of origin of an Earthquake is called the …………..
(a) epicentre
(b) focus
(c) seismic wave
(d) magnitude
Answer:
(a) epicentre

II. Match the following.

Answer:

III. Consider the given statements.

Question 1.
(i) Mt. Fuji is a dormant Volcano.
(ii) Mt. Kilimanjaro is a dormant Volcano.
(iii) Mt. Tanzania is a dormant Volcano.
Which of the statement(s) is are true?
(a) (i) is true
(b) (ii) is true .
(c) (iii) is true
(d) (i) (ii) (iii) are true
Answer:
(a) (i) is true

Question 2.
Statement: Magma gushes out when it finds vents.
Reason: Interior of the Earth contains compressed hot magma.
Which of the statement(s) is are true?
(a) Statement & reason are true
(b) Statement is true, reason is false
(c) Statement is false reason is true
(d) Statement & reason are false
Answer:
(a) is true

Question 3.
Statement I: Mountain ranges are formed by the collision of tectonic plates.
Statement II: The movement of tectonic plates is due to the thermal energy from the mantle.
(a) Statement I is false II is true
(b) Statement I and II are false
(c) Statement I is true II is false
(d) Statement I and II are true
Answer:
(d) is true

IV. Answer the following in one or two sentences.

Question 1.
Write a brief note on the various spheres of the Earth.
Answer:
(i) The Earth is divided into Biotic and ABiotic Spheres.

(ii) Biotic sphere is the Biosphere
A Biotic sphere is further divided into Lithosphere, Atmosphere and Hydrosphere.

Question 2.
Mention the layers of the interior of the Earth.
Answer:
The structure of the earth’s interior is divided into three layers namely the crust, the mantle, the core.

1. The crust is the outer layer of the earth, where we live. The major elements of crust are silica (Si) and aluminium (Al). Hence it is named SIAL.
2. The mantle is the interior part beneath the crust. The major elements of the mantle are silica (Si) and magnesium (Mg). Hence it is called SIMA.
3. The core is the innermost and hottest layer of the earth. It is composed mainly of nickel (Ni) and iron (Fe). Hence it is called NIFE.

Question 3.
What is pedosphere?
Answer:
The ‘Pedosphere’ is part of the lithosphere made up of soil and dirt. It exists at the interface of the lithosphere, atmosphere, hydrosphere, and biosphere.

Question 4.
Define Plate tectonics.
Answer:

1. The word Tsunami is a Japanese term, means harbour waves.
2. It refers to large seismically generated sea waves caused by Earthquakes, submarine explosions, and landslides.
3. These waves travel at a great speed (more than 500 km per hour) and the length of the waves exceeds 600 km.
4. These waves reach a height of more than 15m near the seashore and are capable of causing destruction along the coastal area.

Question 5.
Write a note on Fold and fault?
Answer:
Folding: Due to lateral compressional forces, the plates are forced to move upwards and downwards. This is called folding.
Faulting: The movement of plates also creates stress and tension in the rocks, causing them to stretch and crack. This called ‘faulting’.

Question 6.
What is a Tsunami?
Answer:

1. Earthquakes generate seismic waves.
2. The nature, force, and speed of these seismic waves depend on the nature of the medium through which it
3. The point of origin of an earthquake is called focus
4. The epicenter is a point on the Earth surface that lies directly above the focus
5. The impact of the earthquake is felt most at the epicenter

Question 7.
What is a Volcano? Mention its major components.
Answer:
A volcano is a vent or an opening on the surface of the Earth’s crust through which hot solid, liquid, and gaseous materials (Magma) erupt out to the surface from the Earth’s interior.

Question 8.
What is an Earthquake and how it occurs?
Answer:

1. Most Earthquakes and Volcanic eruptions do not strike randomly but occur along the plate boundaries.
2. One such area is the circum – Pacific Ring of Fire.
3. Here the Pacific Plate meets many surrounding plates. The Ring of Fire is the most seismically and volcanically active zone in the world.

Question 9.
What are seismic waves and mention their types?
Answer:
Earthquakes generate seismic waves. The nature force and speed of these seismic waves depend on the nature of the medium through which it passes.
The major types are

• Primary (or) P waves
• Secondary (or) S waves
• Surface waves (or) L waves.

Question 10.
Write about the Pacific Ring of fire.
Answer:

• The Pacific Ring of Fire is an arc around the Pacific Ocean where many volcanoes are found.
• The Pacific Ring of Fire is the most seismically and volcanically active zone in the world.

V. Give Reasons for the following.

Question 1.
SIAL floats over SIMA.
Answer:

1. SIAL floats over SIMA because SIAL is less dense and lighter.
2. SIAL consists of Silica and Aluminium which is lighter than SIMA which contains silica and Magnesium. Therefore SIAL floats or SIMA.

Question 2.
Igneous rocks are also called Primary Rocks or Mother rocks.
Answer:
Igneous rocks are also called Primary Rocks (or) Mother rocks because all other rocks are directly or indirectly formed from them.

VI. Distinguish between.

Question 1.
Core and crust.
Answer:

S.No.	Core	Crust
(i)	The core is the innermost hottest layer of the earth and the true centre.	The crust is the outer layer of the earth.
(ii)	It is composed mainly of Nickel (Ni) and Iron (Fe). So it is termed as NIFE.	It is composed of Silica and Aluminium. So it is termed as SIAL.
(iii)	Denser materials exist within Earth’s core.	Lighter materials exist on the surface.

Question 2.
Epicentre and Hypocentre.
Answer:

S.No.	Epicentre	Hypocentre
(i)	Epicentre is a point on the Earth’s surface that lies directly above the focus.	It is a point within the earth where an earthquake rupture starts.
(ii)	The impact of the Earthquake is felt, the most at the centre.	It generates series of elastic waves.

Question 3.
Divergent and convergent boundaries.
Answer:

Divergent Boundary	Convergent Boundary
The plates pull away from each other as magma pushes up from the mantle.	The plate moves towards each other and sometimes a plate sinks under another.

Question 4.
Primary waves and Secondary waves.
Answer:

S.No.	Primary waves	Secondary waves
(i)	These waves are the fastest of all the Earthquake waves and the first to reach the epicentre.	Secondary waves travel less faster than the primary waves.
(ii)	These waves pass through solids, liquids and gases.	These waves travel only through solids.
(iii)	The average velocity of these waves is -5.3 k.m/sec to 10.6 k.m/second.	The average velocity of these waves is 1 k.m/sec to 8 k.m/second.

Question 5.
Shield Volcano and Volcanic Dome.
Answer:

S.No.	Shield Volcano	Volcanic Dome
(i)	Shield volcanoes are formed by intense viscous lava.	A lava dome (or) Volcanic dome is roughly circular mound formed due to the slow ejection of viscous lava from a volcano.
(ii)	As the lava is rich in silica with intense viscosity, it is prevented from flowing far from its vent, e.g., Paricutin, Mexico.	These are shallow depositions with gently sloping sides. Hence the lava flows out in all directions to create a shield, e.g., Mauna Loa, Hawai.

VII. Write answers in a Paragraph.

Question 1.
Describe the structure of the Earth.
Answer:
(a) The structure of the Earth:

1. The outer surface and inner core of the earth are totally different in their nature and structure.
2. The structure of the earth’s interior is divided into three layers namely the crust, the mantle and the core.

(b) Crust:

1. Crust is the outer layer of the earth, where we live
2. It is the solid and rigid layer of the earth.
3. The thickness of the crust is greater below the continents than the ocean floor.
4. The crust is classified as the continental crust and oceanic crust.
5. The major elements of crust are silica and aluminium, hence it is called SIAL.

(c) Mantle:

1. The interior part beneath the crust is called the mantle, which is about 2,900 km thick.
2. The major elements of the mantle are silica and magnesium hence it is known as SIMA.
3. In the upper part of the mantle, the rock remains solid, whereas, in the lower part of the mantle, rocks arc in molten form.
4. This molten rock inside the Earth is called ‘magma’

(d) Core:

1. The core is the innermost and hottest layer of the earth which lies below the mantle.
2. It is composed mainly of nickel and iron, hence it is called NIFE.
3. The core is divided into solid inner core and liquid outer core.
4. The presence of large quantities of iron in the core is responsible for the earth’s gravitational force.
5. As the earth rotates on its axis, the liquid outer core spins over the solid inner core and generates the earth’s magnetic field.

Question 2.
Write a note on the internal and external processes of Earth.
Answer:
The formation and deformation of landforms on the surface of the Earth is a continuous activity of two broad processes i.e. internal and external. These processes cause stress and deformation on Earth materials and finally bring changes on the surface of the Earth. These are referred as Geomorphic Processes.

The forces that act from the Earth’s interior towards the Earth’s surface are called Internal processes or Endogenetic processes. These forces build the landscape and create topographic relief.

The forces that act on the surface of the Earth due to natural agents like running water, glacier, wind, waves etc. are called External processes or Exogenetic processes. These external processes tear the landscape down into relatively low elevated plains.

Question 3.
How are volcanoes classified based on the periodicity of their eruptions?
Answer:
Based on the periodicity of eruptions, volcanoes are classified into
(a) Active volcano
(b) Dormant volcano
(c) Extinct volcano.

(a) Active Volcano:
Active volcanoes are those which constantly eject volcanic lava, gases, and fragmented materials.
Eg: Mount St. Helens in the United States.

(b) Dormant Volcano:
Volcanoes that do not show any sign of volcanic activity for a long period of time are known as dormant volcanoes.
Sometimes there may be a sudden explosion which may cause unimaginable loss to life and property.
Eg: Mt. Fuji, Japan

(c) Extinct or Dead Volcano
When a volcano permanently stops its volcanic activity, then it is called an extinct or dead volcano.
Eg: Mt. Kilimanjaro, Tanzania.

Question 4.
Explain the effects of Volcanoes.
Answer:
Effects of volcanoes can be given under two groups as constructive effects and destructive effects.
(a) Constructive Effects:

1. Volcanic materials enrich the soil fertility that promotes agricultural activities.
2. The hot volcanic regions help in generating geothermal energy.
3. Many dormant and active volcanoes are the most attractive tourist spots in the world.
4. Most of the volcanic materials are used as building materials.

(b) Destructive Effects:

1. Volcanic eruption causes earthquakes to fast floods and mudslides and rockfall.
2. Lava can travel very far and bum, bury or damage anything in its path.
3. A large amount of dust and ash makes breathing hard and irritable.
4. Volcanic emotions can alter the weather conditions and disrupt transport (Iceland volcanic emotion) in and around the volcanic region.

VIII. Map Skill.

On the given outline map of the world, mark the following:
(a) Pacific Ring of fire
(b) Earthquake-prone zones (any two)
(c) Locate any two active volcanoes of the world
(d) Himalayas and Alps ranges
(e) Rift valley of East Africa
Answer:
(a) Pacific Ring of fire: It is a major area and an arc in the basin of the Pacific ocean where many earthquakes and volcanic emptions occur.

(b) Earthquake prone zones (any two): Turkey, Indonesia

(c) Locate any two active volcanoes of the world: Hawaii, Mount Fujji

(d) Himalayas and Alps ranges

(e) Rift valley of East Africa

IX. Higher Order Thinking Skills (HOTs) Questions.

Question 1.
Consider the various sources of information related to the Earth’s Interior. Classify the above as DIRECT & INDIRECT sources of information. Give reasons.
Answer:
• Seismic activity
• Earth’s magnetism
• Volcanoes
• Mined rocks
• Gravitational force
• Meteors

• Seismic Activity: Frequency and size of an earthquake.
• Earth’s magnetism: Due to the movement of molten material under the earth’s crust.
• Volcanoes: A rupture in the crust of a planetary-mass object such as Earth, that allows hot lava, volcanic ash & gases to escape.
• Mined Rocks: Excavating hard minerals:
• Gravitational force: A natural phenomenon.
• Meteors: A bright streak of light.

Question 2.
Scientists use GPS to measure the rate of Tectonic Plate movements. Discuss.
Answer:
GPS works by sending radio signals from satellites to ground stations. The distance between the satellites and the station is recorded. Over time, these distances change slightly. Scientists can measure the rate of Tectonic Plate movements by recording the time it takes for ground stations to move a given distance.

In-text HOTs Question

Question 1.
Pacific Ring of Fire — Most seismically and volcanically active. Why?
Answer:
The Pacific Ring of fire is an arc around the Pacific Ocean. It is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and plate movements. It has 452 volcanoes (more than 75% of the world’s active and dormant volcanoes). The Ring of Fire is a direct result of plate tectonics: the movement and collisions of lithospheric plates. That is why it is the most seismically and volcanically active zone in the world.

X. Life Skills

Imagine that you feel tremors or shocks in your locality. What will be your role in saving • lives from destruction? List out the Do’s and Don’ts.
Answer:

(a) Do’s

1. Dropdown onto your hands and knees. This can protect you from falling but allows you to still move if necessary.
2. Cover your hand and neck and your entire body if possible under a study-table or desk. If there is no shelter nearby, only then should you get down near an interior wall or next to low-lying furniture that won’t fall on you and cover your head and neck with your arms and hands.
3. Hold on to your shelter or to your head and neck until the shaking stops. Be prepared to move with your shelter if the shaking shifts it around.

(b) Dont’s

1. Do not run outside or to other rooms during shaking. The area near the exterior walls of a building is the most dangerous place to be. Windows, facades, and architectural details are often the first parts of the building to collapse.
2. Do not stand in a doorway. In modem houses, doorways are no stronger than any other part of the house and the doorway does not protect you from the most likely source of injury.
3. If you are outside, do not go near power lines or electric units. Move away from buildings, trees, street lights, and utility wires. If you are in an open space, stay there till the shaking stops.

More Instructions:

1. Stay calm and do not panic.
2. Avoid going near the beach after the earthquake is over as a strong earthquake can set off a tsunami.
3. If possible have supplies set aside in an emergency kit.
4. You may include first aid, bottled water, canned or dried food to carry during an emergency.

Student Activities

Question 1.
Collect a few rock samples from your area and classify them on the basis of what you have learned.
Answer:
You can do this activity under the guidance of your teacher.

Question 2.
Narrate the processes involved in the given rock cycle diagram in your own words.
Answer:

Rocks are continually changing from one type to another and back again. Rock Cycle is the geologic process that describes the transition of rocks between the three rock types: igneous, sedimentary, and metamorphic. The forces inside the earth bring the rocks closer to the surface. Here the rocks are weathered, eroded, and compacted. Then the forces on the earth sink the rocks. Back down, the rocks are heated, pressed, and melted. So the elements that create rocks are constantly being recycled.

Question 3.
Here is a list of a few mountains.

• Ural Mountains, Andes Mountains, Vindhya Range, Alps mountains
• Satpura range, Rocky Mountains, Sierra Nevada.
• Identify and Locate with help of an atlas

Answer:
You can identify and locate the above-mentioned mountains with the help of an atlas or the Internet.

Question 4.
(a) Arrange a few books one above the other on a table. Just shake the table and observe what happens.
Answer:
You can do this activity under the guidance of your teacher.

(b) Ask two students to hold two ends of a rope. Instruct one of them to shake the rope, while the other holds it lightly and then firmly. What do you observe?
Answer:
You can do this activity under the guidance of your teacher.

Question 5.
Take a bottle filled with soda. Give it a few shakes. Now twist the cap open. What do you observe?
Answer:
A capped bottle is under uniform pressure. The molecules of carbon dioxide gas and liquid are at equilibrium (due to a uniform pressure). When we shake the bottle, the contents are pressurized. So when the cap is opened, the liquid comes out with a force and fizzes.

Lithosphere – I Endogenetic Processes Additional Questions

I. Choose the correct answer.

Question 1.
This is the solid outer part of the Earth.
(a) Lithosphere
(b) Atmosphere
(c) Hydrosphere
(d) Biosphere
Answer:
(a) Lithosphere

Question 2.
Earths’ surface is a vast area of _______ million.
(a) 490
(b) 510
(c) 500
(d) 520
Answer:
(b) 510

Question 3.
This is the storehouse of rocks.
(a) crust
(b) core
(c) mantle
(d) None of the above
Answer:
(a) crust

Question 4.
The word ‘Igneous’ is derived from the …………… word.
(a) Arabic
(b) Roman
(c) Latin
(d) Sanskrit
Answer:
(c) Latin

Question 5.
An aggregate of minerals on the Earth’s Crust is called _______
(a) Magma
(b) Waves
(c) Rock
(d) Core

Question 6.
These waves are the fastest of all the Earthquake waves.
(a) P – waves
(b) S – waves
(c) L- waves
(d) None of the above
Answer:
(a) P – waves

Question 7.
The sixth deadliest natural disaster due to the Tsunami caused in the year …………..
(a) 1996
(b) 1998
(c) 2000
(d) 2004
Answer:
(d) 2004

Question 8.
…………… is a vent (or) and opening on the surface of the Earth crust.
(a) Volcano
(b) Tsunami
(c) Earthquake
(d) None of the above
Answer:
(a) Volcano

Question 9.
Seismology deals with __________
(a) Tsunami
(b) Earthquakes
(c) Volcano
(d) Crust
Answer:
(b) Earthquakes

Question 10.
Composite volcanoes are commonly found in the ………….. ocean.
(a) Pacific
(b) Southern
(c) Indian
(d) Atlantic
Answer:
(a) Pacific

II. Match the following.
(a)

Answer:
1. (b)
2. (c)
3. (a)
4. (e)
5. (d)

b.

Answer:
1. (d)
2. (a)
3. (b)
4. (c)

III. Consider the given statements

Question 1.
(i) When magnia reaches this Earth’s surface, it is referred to as ‘Lava’. (True)
(ii) The interior of the earth contains very hot molten material called ‘Magma’. (True)
(iii) Sedimentary are also called Primary (or) Mother rocks. (False)
(a) (i) is true
(b) (i) & (ii) are true (iii) false
(c) (iii) is true
(d) (i), (ii), (iii) are true
Answer:
(b) (i) and (ii) are true (iii) false

Question 2.
(i) The plates move vertically in convergent Boundary. (False)
(ii) The plates pull away from each other in the Transform boundary. (False)
(iii) The plates slide horizontally past each other in Transform Boundary. (True)
(a) (i) is false
(b) (i) and (ii) are false
(c) (ii) false (i) and (iii) are true
(d) (i) (ii) are false (iii) true
Answer:
(i) (ii) are false (iii) true

IV. Answer the following questions in one or two sentences.

Question 1.
What is Hydrosphere?
Answer:
The Hydrosphere is the watery part of the Earth’s surface including oceans, rivers, lakes, and water vapour.

Question 2.
What are fossils?
Answer:
The bodies of plants and animals that fall on the sedimentary rock deposits get embedded in the layers and form fossils.

Question 3.
What do you know about the Active Volcano?
Answer:
Active volcanoes are those which constantly eject volcanic lava, gases, and fragmented materials, e g., Mount St. Helens in the United States.

Question 4.
What is Geology?
Answer:
Science deals with the physical structure and substances of the earth their history and the processes which act on them.

Question 5.
What do the internal processes generate?
Answer:

• The internal processes generate heat and eject materials from deep below the Earth’s crust.
• Internal radioactivity is the principal source of power for this process.

V. Give reasons for the following.

Question 1.
Why did Tsunami occur on 26th December 2004?
Answer:

• It was the result of the Indo-Australian plate subducting below the Eurasian plate.
• It was caused by an earthquake measuring a magnitude of above 9 in the Richter scale.
  Hence the seafloor was uplifted, displacing the sea water above.

Question 2.
Why does the lava flow out in all directions in the shield volcano?
Answer:

• Shield volcanoes are formed by intense viscous, lava.
• These are shallow depositions with gently sloping sides.
• Hence the lava flows out in all directions to create a shield.

VI. Distinguish between:

Question 1.
Internal Processes and External processes.
Answer:

S.No.	Internal Processes	External processes
(i)	The forces that act from the Earth’s interior toward the Earth’s surface are called Internal processes.	The forces that act on the surface of the Earth due to natural agents like running water, glacier, wind, waves, etc., are called External processes.
(ii)	These forces build the landscape and create topographic relief.	These external processes tear the landscape down into relatively low elevated plains.

Question 2.
Seismology and Geology.
Answer:

Seismology	Geology
The science that deals with Earthquakes are called seismology’	Science that deals with the physical structure and substance of the earth their history and the processes which act on them.

Question 3.
Atmosphere and Biosphere.
Answer:

Atmosphere	Biosphere
The atmosphere is a thin layer of gases that surround the Earth.	The Biosphere is the layer of Earth where life exists.

VII. Write answers in a Paragraph.

Question 1.
Give an account tsunami.
Answer:

1. The word Tsunami is a Japanese term meaning harbour waves.
2. It is adopted to describe large seismically generated sea waves caused by Earthquakes, submarine explosions, and landslides.
3. These waves travel at a great speed (more than 500 km/hr) and the length of the waves exceeds 600 kms.
4. These waves reach a height of more than 15 m near the seashore and are capable of causing destruction along the coastal area.
5. On 26th December 2004, a tsunami occurred in the Indian ocean.
6. It was the result of the Indio-Australian Plate subducting below the Eurasian plate.
7. lt was caused by an earthquake measuring a magnitude of above 9 in the Richter Scale.
8. The Earthquake caused the seafloor to uplift, displacing the seawater above.