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

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Social Science Guide Pdf Geography Chapter 1 Lithosphere – I Endogenetic Processes Text Book Back Questions and Answers, Important Questions, Notes.

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

Samacheer Kalvi 9th Social Science Lithosphere – I Endogenetic Processes Text Book Back Questions and Answers

I. Choose the correct answer

Question 1.
___________ is the rigid outer layer of the Earth.
(a) Core
(b) Mantle
(c) Crust
(d) Inner core
Answer:
(c) Crust

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

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:
(d) fold/fault

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

Question 6.
In the ancient period, Gondwanaland moved towards ___________
(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

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

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:
(b) focus

II. Match the following

  1. Endogenetic process – (i) Seismograph
  2. Mantle – (ii) Subduction Zone
  3. Convergent boundaries – (iii) Volcanic
  4. Earthquake – (iv) Pacific Ocean
  5. Composite volcano – (v) SIMA

Answer:

  1. – iii
  2. – v
  3. – ii
  4. – i
  5. – iv

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) Statement & reason are 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) Statement I and II are true

IV. Answer in brief:

Question 1.
Write a brief note on the various spheres of the Earth.
Answer:
The various spheres of the earth are given below:

  1. The lithosphere is the solid outer part of the Earth.
  2. The atmosphere is a thin layer of gases that surrounds the Earth.
  3. The hydrosphere is the watery part of the earth’s surface including oceans, rivers, lakes and water vapour.
  4. The biosphere is the layer of earth where life exists.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

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. 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 as SIAL.
  2. Mantle is the intereior 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.
Define Plate tectonics.
Answer:

  1. The lithosphere is divided into a number of huge slabs of rocks called ‘Tectonic Plates’.
  2. These tectonic plates are divided into major and micro plates.
  3. These plates float independently over the mantle.
    What are seismic waves and mention its types?
  4. Collisions of these plates produce mountain ranges and other irregular surface features, both on land and the ocean floor.
  5. This phenomenon is called plate tectonics.

Question 4.
What is Tsunami?
Answer:

  1. The word Tsunami is a Japanese terms, means harbour waves.
  2. It refers to large seismically generated sea waves caused by Earthquakes, submarine explosions and land slides.
  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 to a height of more than 15m near sea shore and are capable of causing destruction along the coastal area.

Question 5.
What is a Volcano? Mention its major components.
Answer:

  1. A volcano is a vent or an opening on the surface of the Earth crust through which hot solid, liquid and gaseous materials (magma) erupt out.
  2. It erupts from the earth’s interior, to the surface.
  3. Its major components are Magma Chamber, Vents and Volcanic cone.

Question 6.
What is an Earthquake and how its occur?
Answer:

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

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 7.
What are seismic wave and mention its type?
Answer:

  1. Earthquakes generate seismic wave
  2. These vibretions spread out
  3. Accordingly there are three major types of waves
  4. They are –
    • Primary or P-Waves
    • Secondary or S-Waves
    • Surface waves or L-Waves.

Question 8.
Write about the Pacific Ring of fire.
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.

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 called Primary or Mother Rocks because all other rocks are directly or indirectly formed from them.

VI. Distinguish between:

Question 1.
Core and Crust
Answer:
Core –

  1. The core is the innermost and hottest layer of the earth.
  2. It lies below the mantle.
  3. It is composed mainly of nickel and iron.
  4. It is called NIFE.

Crust –

  1. Crust is the outer layer of the earth, where we live.
  2. It lies above the mantle.
  3. The major elements of crust are silica and aluminium.
  4. It is called SIAL.

Question 2.
Epicentre and Hypocentre
Answer:

Epicentre –

  1. Epicentre is a point on the Earth’s surface that lies directly above the focus.
  2. The impact of the earthquake is felt the most at the epicentre.

Hypocentre –

  1. The point of origin of an earthquake is called Focus or Hypocentre.
  2. It generates a series of elastic waves.

Question 3.
Divergent and convergent boundaries
Answer:
Divergent Boundaries –

  1. Here the plates pull away from each other.
  2. Most active divergent plate boundaries occur between oceanic plates and exist as mid-oceanic ridges.
  3. Divergent boundaries also form volcanic islands.

Convergent Boundaries –

  1. Here the plates move towards each other and sometimes a plate sinks under another.
  2. The location where the sinking of a plate occurs is called a subduction zone.
  3. The subducting plate in a subduction zone is normally an oceanic crust.

Question 4.
Primary waves and Secondary waves.
Answer:
Primary Waves

  1. Primary or P waves are the fastest of all the Earthquake waves.
  2. They are the first to reach the epicentre
  3. These waves pass with an average, velocity of 5.3 km per second to 10.6 km/second.

Secondary Waves –

  1. Secondary or S waves travel only through solids.
  2. These transverse waves shake the ground perpendicular to the direction in which they propogate.
  3. These waves pass with an average velocity of 1 km/sec to 8 km/second.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 5.
Shield volcano and Volcanic Dome
Answer:
Shield Volcano –

  1. Shield volcanoes are formed by intense viscous lava.
  2. These are shallow depositions with gently sloping sides
  3. The lava flows out in all directions to create a shield.
  4. Eg: Mauna Loa, Hawaii.

Volcanic Dome –

  1. Volcanic dome is formed due to the slow ejection of viscous lava from a volcano.
  2. It is a lava dome roughtly a circular mound.
  3. As the lava is rich in silica with intense viscosity, it is prevented from flowing far from its vent.
  4. Eg: Paricutin, Mexico.

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 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 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, where as, 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 the Earth.
Answer:
The internal and external processes of earth are given below:
(a) Geomorphic processes:

  1. 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.
  2. These processes cause stress and deformation on earth materials and finally bring changes on the surface of the earth.
  3. These are referred to as geomorphic processes.

(b) Internal Processes (or) Endogenetic processes:

  1. The forces that act from the earth’s interior towards the earth’s surface are called internal processes endogenetic processes.
  2. These forces build the landscape and create topographic relief.
  3. The internal processes generate heat and eject materials from deep below the earth’s crust.
  4. Internal radioactivity is the principal source of power for this process.

(c) External Proesses (or) Exogenetic Processes:

  1. 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.
  2. 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:

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

(b) Dormant Volcano:

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

(c) Extinct or Dead Volcamo

  1. When a volcano permanently stops its volcanic activity, then it is called an extinct or dead volcano. Eg: Mt. Kilimanjaro, Tanzania.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

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 helps in generating geothermal energy.
  3. Many dormant and active volcanoes are the most attractive tourist spots of the world.
  4. Most of the volcanic materials are used as building materials.

(b) Destructive Effects:

  1. Volcanic eruption causes earthquakes fast floods and mud slide and rock fall.
  2. Lava can travel very far and bum, bury or damage anything in its path.
  3. The large amount of dust and ash makes breathing hard and irritable.
  4. Volcanic emptions can alter the weather conditions and dismpt transport (Iceland volcanic emption) 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.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

IX. HOTS

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
(a) Seismic activity
(b) Earth‘s magnetism
(c) Volcanoes
(d) Mined rocks
(e) Gravitational force
(f) Meteors
Answer:
Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

  1. The knowledge about the interior of the earth is obtained through direct sources and indirect sources.
  2. Direct sources are not very reliable, because mining and drilling can be done only upto some depth only.

Direct Sources:

  1. Volcanoes: Volcanic eruption suggests that there is same zone inside the Earth, which is very hot and in liquid condition.

Mined rocks:

  1. During the process of mining and drilling, rocks and minerals are extracted. These extracted materials give information that there are layer system in the crust.
  2. Crust is made up of many kinds of rocks and minerals.

Indirect Sources:

  1. Seismic activity, Gravitational force, Earth’s Magnetism, Meteors are very important to know about earth’s interior.

Seismic Activity:

  1. We can use the behaviour of the seismic waves to make aware about the interior of the Earth.
  2. Movement of Seismic Waves suggests that there are three layers on the earth and each layer less different density.
  3. Density increases towards the centre of the earth.

Gravitational force:

  1. Earth’s-core is at its centre of mass, which is what generates our gravitational field.

Earth’s Magnetism:

  1. It is established that the liquid outer core of the Earth produces a kind of electromagnetic field, ie. the Earth’s magnetic field.

Meteors:

  1. We can know about the Earth’s interior by studying Meteorites.
  2. Meteorites have struck the earth in the past. Many have probably pieces of proto-plants i g similar in compostion to Earth.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

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. Drop down 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 and 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 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 many include a first aid, bottled water, canned or dried food to carry during an emergency.

Intext Activity

Question 1.
Narrate the processes involved in the given rock cycle diagram in your own words
Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes
Answer:

  1. The process of transformation of rocks from one form to the other in a cyclic manner is known as the rock cycle.
  2. It includes the following processes : Hot lava cools down to form igneous rocks. Igneous rocks are then broken down into small particles which are transported and then deposited This results in the formation of sedimentary rocks.
  3. When igneous and sedimentary rocks are subjected to great heat and pressure, they change into metamorphic rocks.
  4. Metasmorphic rocks under heat and pressure breakdown and form hot lava. This hot magma then again cools down and forms igneous rocks and the cycle is repeated.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 2.
Here is a list of a few mountains.

  1. Ural Mountains
  2. Andes Mountains
  3. Vindhya Range
  4. Alps mountains
  5. Satpura range
  6. Rocky Mountains
  7. Sierra Nevada.

Identify and Locate with help of atlas –

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 3.
Take a bottle filled with soda. Give it a few shakes. Now twist the cap open. What do you observe?
Answer:
Activity to be done by the students themselves

Intext Hots

Question 1.
Pacific Ring of Fire – Most seismically and volcanically active. Why?
Answer:
(a) The Pacific Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur. In a large 40,000 km (25,000 mi) horseshoe shape.

(b) About 90% of the world’s earthquakes and 81% of the world’s largest earthquakes occur along the Ring of Fire. All but three of the world’s 25 largest volcanic eruptions of the last
11,700 years occurred at volcanoes in the Ring of Fire.

(c) The Ring of Fire is a direct tresult of plate tectonics: the movement and collisions of lithospheric plates, especially subduction in the northern portion.

(d) The southern portion is more complex, with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines,Bougainville ,Tonga,and New Zealand.

Samacheer Kalvi 9th Social Science Lithosphere – I Endogenetic Processes Additional Important Questions and Answers

I. Choose the correct answer:

Question 1.
All the living organisms are found here _______
(a) Lithosphere
(b) Hydrosphere
(c) Pedosphere
(d) Biosphere
Answer:
(d) Biosphere

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

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 3.
Silica and Aluminium are the components of the _______
(a) Crust
(b) Mantle
(c) Core
(d) None of the above
Answer:
(a) Crust

Question 4.
Kola sample title is located in _______
(a) America
(b) Russia
(c) Germany
(d) Singapora
Answer:
(b) Russia

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

Question 6.
Diamond is an example of _______ rock.
(a) Igneous
(b) Sedimentary
(c) Metamorphic
(d) None of the above
Answer:
(c) Metamorphic

Question 7.
In ____________ boundary the plates slide horizontally past each other.
(a) convergent
(b) transform
(c) divergent
(d) horizontal
Answer:
(b) transform

Question 8.
The collision with the Eurasian Plate along the boundary between India and Nepal formed __________ Plateau.
(a) Columbia
(b) Colorado
(c) Tibetan
(d) Antarctic
Answer:
(c) Tibetan

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

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 10.
An opening serving as an outlet for air, smoke, fumes, magma etc. is called
(a) Vent
(b) Magma Chamber
(c) Volcanic Core
(d) Lava
Answer:
(a) Vent

Question 11.
Mauna Loa in Hawaii is an example of
(a) Composite Volcano
(b) Dormant Volcano
(c) Extinct Volcano
(d) Shield Volcano
Answer:
(d) Shield Volcano

Question 12.
Upper layer of the earth’s mantle below the lithosphere is called
(a) Hydrosphere
(b) Pedosphere
(c) Asthenosphere
(d) Atmosphere
Answer:
(c) Asthenosphere

Question 13.
Earthquake is the shaking or trembling of the Earth’s
(a) Crust
(b) Core
(c) Mantle
(d) Oceans
Answer:
(a) Crust

Question 14.
The science that deals with the physical structure and substances of the earth is known as
(a) Biology
(b) Zoology
(c) Geology
(d) Morphology
Answer:
(c) Geology

Question 15.
Volcanic eruption causes I
(a) Earthquakes
(b) Fast Floods
(c) Mud Slide
(d) All the three
Answer:
(d) All the three

II. Match the following:

Question 1.
(a) Lithosphere – (i) Gases
(b) Atmosphere – (ii) Soil and dirt
(c) Hydrosphere – (iii) Life
(d) Biosphere – (iv) Solid
(e) Pedosphere – (v) Water
Answer:
(a) – (iv)
(b) – (i)
(c) – (v)
(d) – (iii)
(e) – (ii)

Question 2.
(a) Crust – (i) 2,171 km
(b) Upper Mantle – (ii) 2,259 km
(c) Lower Mantle – (iii) 30 km
(d) Outer Core – (iv) 1221km
(e) Inner Core – (v) 720 km
Answer:
(a) – (iii)
(b) – (v)
(c) – (i)
(d) – (ii)
(e) – (iv)

Question 3.
(a) Igneous – (i) Magma
(b) Sedimentary – (ii) Transformation
(c) Metamorphic – (iii) Gypsum
(d) Molten material – (iv) Basalt
(e) Rock Cycle – (v) Marble
Answer:
(a) – (iv)
(b) – (iii)
(c) – (v)
(d) – (i)
(e) – (ii)

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 4.
(a) Convergent Boundary – (i) Away from each other
(b) Divergent Boundary – (ii) Tectonic Plates
(c) Transform Boundary – (iii) Towards each other
(d) Huge slabs of rocks – (iv) Folding
(e) Lateral compressional forces – (v) Horizontally past each other
Answer:
(a) – (iii)
(b) – (i)
(c) – (v)
(d) – (ii)
(e) – (iv)

Question 5.
(a) Focus – (i) “‘L-Waves
(b) Surface Waves – (ii) S-Waves
(c) Seismometer – (iii) P-Waves
(d) Secondary Waves – (iv) Hypocenter
(e) Primary Waves – (v) Instrument
Answer:
(a) – (iv)
(b) – (i)
(c) – (v)
(d) – (ii)
(e) – (iii)

Question 6.
(a) Active Volcano – (i) Mt. Kilimanjaro
(b) Dormant Volcano – (ii) Strata Volcano
(c) Extinct Volcano – (iii) Mt. St. Helens
(d) Composite Volcano – (iv) Mt. Fuji
(e) Shield Volcano – (v) Mauma loa
Answer:
(a) – (iii)
(b) – (iv)
(c) – (i)
(d) – (ii)
(e) – (v)

III. Consider the given statements:

Question 1.
Consider the given statements:
(i) The thickness of the crust is greater below the continents than the oceans floor.
(ii) All terrestrial planets have lithosphere.
(iii) The core is composed of Silica and Aluminium.
Which of the statement (s) is/are true?
(a) (i) is true
(b) (ii) is true
(c) (i) and (ii) are true
(d) (iii) is true
Answer:
(c) (i) and (ii) are true

Question 2.
Statement: The Latin word ‘Sediment’ means settle.
Reason: Rivers, glaciers and winds carry lists of rock and soil and deposit than on layers. Which of the following statements(s) is / are true?
(a) Statement and reason are true.
(b) Statement is true, reason is false.
(c) Statement is false, reason is true.
(d) Statement and reason are false
Answer:
(a) Statement and reason are true.

Question 3.
Statement I: Volcanoes can also be classified based on the periodicity of eruptions, as Active volcano, Dormant volcano and Extinct volcano.
Statement II: A lava dome is roughly a circular mound formed due to the slow ejection of viscous lava from a volcano.
Which of the following statements(s) is / are true?
(a) Statement I and II are true.
(b) Statement I and II are false.
(c) Statement I is true but-II is false.
(d) Statement I is false but-II is true.
Answer:
(a) Statement I and II are true.

IV. Answer the following in one or two sentences:

Question 1.
How does Arthur Holmes describe the Earth?
Answer:
The Earth can physically be described as a ball of rock (the lithosphere), partly covered by water (the hydrosphere) and wrapped in an envelope of air (the atmosphere). To these three physical zones it is convenient to add a biological zone which includes all the living organisms (the biosphere). This is the description given by Arthur Holmes about the Earth.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 2.
What are the abiotic and biotic spheres of the earth?
Answer:

  1. The abiotic spheres are the lithosphere, atmosphere and hydrosphere.
  2. The biotic sphere is the biosphere.
  3. Together these spheres constitute the planet, Earth.

Question 3.
What is SIAL?
Answer:

  1. Crust is the outer layer of the Earth, where we live.
  2. The major elements of crust are Silica (Si) and Aluminium
  3. Thus it is called SIAL.

Question 4.
What is SIAM?
Answer:

  1. The interior part beneath the crust is called mantle.
  2. The major elements of the mantle are Silica (Si) and Magnesium (Mg).
  3. Thus it is called SIMA.

Question 5.
What is NIFE?
Answer:

  1. The core is the innermost and hottest layer of the Earth.
  2. It is composed mainly of Nickel (Ni) and Iron (Fe).
  3. Hence it is called NIFE.

Question 6.
Mention the types of rocks based on formation?
The types of rocks based on formation are
Answer:

  1. Igneous rocks
  2. Sedimentary rocks and
  3. Metamorphic rocks.

Question 7.
Mention a few specimens of magnificent rock-cut architecture in India?
Answer:
There are many specimens of magnificent rock-cut architecture in India, like the Ajanta and Ellora caves in Maharashtra, the Aihole Badami temples in Karnataka, the Konark temple in Odisha and Mamallapuram temples in Tamil Nadu.

Question 8.
How are igneous rocks formed?
Answer:

  1. The interior of the Earth contains very hot molten material called Magma.
  2. When the magma reaches the Earth’s surface, it is referred to as Lava.
  3. The Lava on the surface cools down and gets solidified as rocks called igneous rocks.

Question 9.
How are sedimentary rocks formed?
Answer:

  1. The sedimentary rocks are named after the Latin word sediment meaning ‘settle’
  2. Rivers, glaciers and winds carry bits of rock and soil and deposit them in layers.
  3. After a few million years, these deposits harden into compact rocks and are called sedimentary rocks.

Question 10.
What are fossils?
Answer:

  1. The bodies of plants and animals that fall on the deposits get embedded in the layers.
  2. They form Fossils.

Question 11.
What are metamorphic rocks?
Answer:

  1. The term metamorphic is derived from the word ‘metamorphosis’.
  2. It means, ‘change of form’
  3. When igneous or sedimentary rocks are subjected to extreme heat and pressure, they undergo a complete change in their form and character.
  4. In course of time, granite may get transformed to gneiss basalt to schist, limestone to marble and sandstone to quartzite.

Question 12.
What are Geomorphic processes?
Answer:

  1. The formation and deformation of landforms on the surface of the Earth in a continuous activity of two broad processes.
  2. They are internal and external processes.
  3. These processes cause stress and deformation on Earth materials.
  4. Finally changes are brought on the surface of the Earth.
  5. These are referred as Geomorphic Processes.

Question 13.
What is a subduction zone?
Answer:

  1. In Convergent boundary, the plates move towards each other and sometimes, a plate sinks under another.
  2. The location where the sinking of the plate occurs is called a subduction zone.

Question 14.
What are seismic waves?
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 passes.
  3. Accordingly there are three major types of waves called primary waves, secondary waves and surface waves

Question 15.
How did Tsunami occur with Indian Oceans in 2004?
Answer:

  1. On 26th December 2004 a tsunami occurred in the Indian Ocean.
  2. It was the result of the Indio-Australian plate subducting below the Eurasion Plate.
  3. It was caused by an Earthquake measuring a magnitude of above 9 in the Richter Scale.
  4. The Earthquake caused the seafloor to uplift, displacing the seawater above.

Question 16.
Explain the major components of a volcano.
Answer:

  1. Volcanoes generally have the following major components. They are:
  2. Magma Chamber – a large pool of liquid rock found beneath the surface of the Earth.
  3. Vents – an opening serving as an outlet for air, smoke, fames, magma etc.
  4. Volcanic cone – a landform built by the magma ejected from the vent in the shape of a cone.

V. Give reasons for the following:

Question 1.
The Earth’s gravitational force
Answer:
The presence of large quantities of iron in the core is responsible for the Earth’s gravitational force.

Question 2.
Generation of the Earth’s Magnetic field.
Answer:
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 3.
The cause of the functioning of the magnetic compass
Answer:
The Earth’s magnetic field is responsible for the functioning of the magnetic compass.

Question 4.
Himalayas are fold mountains
Answer:

  1. Due to lateral compressional forces, the plates are forced to move upwards and downwards.
  2. This is called folding.
  3. Mountains formed by folding are called fold mountains.
  4. The process of folding creates lofty mountain ranges such as the Himalayas.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 5.
Continuous reshaping of the continents and sea floor.
Answer:
The process of folding and faulting together with volcanoes and Earthquakes continually reshape the continents and sea floor.

Question 6.
Formation of the Tibetan Plateau.
Answer:

  1. The collision with the Eurasian Plate along the boundary between India and Nepal formed the orogenic belt.
  2. This created the Tibetan Plateau and the mighty Himalayan mountains.

Question 7.
A lava dome does not flow for from into vent.
Answer:

  1. In a lava dome, the lava is rich in Silica with intense viscosity.
  2. So it is prevented from flowing far from its vent.

VI. Distinguish between:

Question 1.
Crust and Mantle.
Answer:
Crust –

  1. Crust is the outer layer of the Earth, where we live.
  2. It ranges between 5 to 30 km.
  3. It is composed of Silica and Aluminium.
  4. It is called SIAL.

Mantle –

  1. The interior part beneath the crust is called mantle.
  2. It is about 2,900 km thick.
  3. It is composed of Silica and Magnesium.
  4. It is called SIMA.

Question 2.
Sedimentary Rocks and Metamorphic Rocks
Answer:
Sedimentary Rocks –

  1. Rivers, glaciers and winds carry bits of rock soil and deposit them in layers. After a million years these deposits harden into compact rocks called sedimentary rocks.
  2. ‘Eg: Sand stone, limestone, chalk, gypsum, coal etc.

Metamorphic Rocks –

  1. When igneous or sedimentary rocks are subjected to extreme heat and pressure, they undergo a complete change in their form and character.
  2. Eg: Granite transformed into gneiss, basalt to schist, limestone to marble, sandstone to quartzite

Question 3.
Internal Processes and External Processes
Answer:
Internal Processes –

  1. The forces that act from the Earth’s interior towards the Earth’s surface are called Internal Processes.
  2. Internal processes are also known as Endogenetic processes.
  3. These forces build the landscape and create topographic relief.

External Processes –

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

Question 4.
Active Volcano and Dormant Volcano
Answer:
Active Volcand –

  1. The Active volcanoes constantly eject volcanic lava, gases and fragmented materials.
  2. Eg: Mount St. Helens in the USA

Dormant Volcano –

  1. The dormant volcanoes do not show any sign of volcanic activity for a long period of time. Sometimes there may be a sudden explosion.
  2. Eg. Mt. Fuji, Japan

VII. Write answers in a paragraph.

Question 1.
Explain about the rocks based on formation
Answer:
Based on formation, rocks are classified as:
(a) Igneous
(b) Sedimentary
(c) Metamorphic

(a) Igneous:

  1. When the lava on the surface cools down and solidified igneous rocks are formed.
  2. Granite and basalt are the examples of such rocks.
  3. Igneous rocks are also called Primary or mother rocks because all other rocks are directly or indirectly formed from them.
  4. These rocks are used in the construction work and laying roads.

(b) Sedimentary Rocks:

  1. Rivers, glaciers and winds cany lists of rock and soil and deposit them in layers.
  2. After a few millions years, these deposits harden into compact rocks.
  3. They are called sedimentary rocks.
  4. The bodies of plants and animals that fall on the deposits get embedded in the layers and form Fossils.
  5. Sandstone, limestone, chalk, gypsum, coal are examples.
  6. These rocks are useful in manufacturing of wall board, cement, plaster of Paris, construction and purification of iron in blast furnaces etc.

(c) Metamorphic Rocks:

  1. When igneous or sedimentary rocks are subjected to extreme heat and pressure, they ‘ undergo a complete change in their form and character.
  2. In course of time, granite may get transformed to gneiss, basalt to schist, limestone to marble and sandstone to quartzite.
  3. These rocks are used in Jewellary making, sculpture and construction.

Question 2.
Write a note on 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 to a height of more than 15 m near the sea shore 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.

VIII. Higher Order Thinking Questions (Hots)

Question 1.
Explain the terms
(a) Diastrophism
(b) Volcanism
Answer:
(a) Diastrophism:

  1. All processes that move, elevate or buildup portions of the earth’s crust come under diastrophism.
  2. In the process of orogeny, the crust is severely deformed into folds.
  3. Due to Epeirogenic processes, uplift or warping of large parts of the crust of the Earth takes place.

(b) Volcanism:

  1. Volcanism includes the movement of molten rock (magma) onto or towards the Earth’s surface.
  2. Formation of many intensive and extensive volcanic forms takes place

Question 2.
What is the difference between the ‘magnitude’ and the ‘intensity’ of an earthquake.
Answer:

  1. The intensity scale is designed to describe the effects of an earthquake, at a given place, on natural features, on industrial installations and on human beings.
  2. Magnitude is related to the energy released by an earthquake.

Samacheer Kalvi 9th Social Science Guide Geography Chapter 1 Lithosphere - I Endogenetic Processes

Question 3.
Will more shocks be felt after a strong earthquake?
Answer:

  1. For several hours, or even days, after a strongly felt earthquake, it is quite possible that people may, feel more shocks.
  2. This possibility always exists, but keep in mind the four facts:-
  3. In mosts cases, these shocks (called aftershocks) will be smaller, therefore, the vibrations will be weaker.
  4. Aftershocks do not mean that a stronger earthquake is coming.
  5. Aftershocks are normal, they show that the earth’s crust is readjusting after the main earthquake.
  6. The number of aftershock felt is quite variable and thus cannot be predicted. There might be several per day or only several per week.

Question 4.
What is Tsunami Warning System (TWS)?
Answer:

  1. ATsunami warning system (TWS) is used to detect Tsunamis in advance and issue warnings to prevent loss of life and damage.
  2. It is made up of two equally important components.
  3. There is a network of sensors to detect Tsunamis.
  4. And there is a communication infrastructure to issue timely alarms to permit evacuations of the coastal areas.

Question 5.
Pacific Ring of Fire – What do you understand by the term?
Answer:

  1. This is with Pacific region where several tectonic plates meet.
  2. The only problem in that these plates are constantly floating on mantle.
  3. Because they float around, they either collide with each other, or, they are pulled apart or they just slide along each other.
  4. When the tectonic plates collide, they form convergent boundaries where subduction zones are created.
  5. When the tectonic plates are pulled apart, they create what are known as divergent boundaries.
  6. Then there are transform boundaries that are created when two tectonic plates slide along each other.
  7. Because Magma is involved which continuously rises from underneath, forming volcanoes and bridges.
  8. This area is called the Ring of Fire.
  9. Of course the fiery lava that is splitout by the active volcanoes with ring also responsible for the name.

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