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Geography 1. Lithosphere – I Endogenetic Processes Class 9th Social Science Term 1 Tamilnadu Board Solution

Class 9th Social Science Term 1 Tamilnadu Board Solution
Exercise
  1. The is the rigid outer layer of the Earth. Choose the correct answer:…
  2. ______ layer is made up of liquid iron Choose the correct answer:…
  3. Magma is found in the _______ Choose the correct answer:
  4. Diastrophism is connected to Choose the correct answer:
  5. The movement of tectonic plates is induced by ______ energy. Choose the correct answer:…
  6. In the ancient period, Gondwana land moved towards ______ direction. Choose the correct…
  7. Many million years ago, India was a part of the supercontinent _____ Choose the correct…
  8. The movement of plates that creates stress and tension in the rocks causing them to…
  9. _______refers to a bowl-shaped depression found at the top of the volcano. Choose the…
  10. The point of origin of an Earthquake is called the _______ Choose the correct answer:…
  11. Match the following1.Endogenetic processSeismograph2.MantleSubduction Zone3.Convergent…
  12. i. Mt. Fuji is a dormant volcanoii. Mt. Kilimanjaro is a dormant volcanoiii. Mt. Tanzania…
  13. Statement: Magma gushes out when it finds vents.Reason: Interior of the Earth contains…
  14. Statement I: Mountain ranges are formed by the collision of tectonic platesStatement II:…
  15. Write a brief note on the various spheres of the Earth. Answer the following in one or two…
  16. Mention the layers of the interior of the Earth. Answer the following in one or two…
  17. What is pedosphere? Answer the following in one or two sentences:…
  18. Define Plate tectonics. Answer the following in one or two sentences:…
  19. Write a note on Fold and fault? Answer the following in one or two sentences:…
  20. What is a Tsunami? Answer the following in one or two sentences:
  21. What is a Volcano? Mention its major components. Answer the following in one or two…
  22. What is an Earthquake and how it occurs? Answer the following in one or two sentences:…
  23. What are seismic waves and mention its types? Answer the following in one or two…
  24. Write about the Pacific Ring of fire. Answer the following in one or two sentences:…
  25. SIAL floats over SIMA. Give Reasons for the following:
  26. Igneous rocks are also called Primary Rocks or Mother rocks. Give Reasons for the…
  27. Core and crust. Distinguish between:
  28. Epicentre and Hypocentre Distinguish between:
  29. Primary waves and Secondary waves. Distinguish between:
  30. Shield volcano and volcanic Dome. Distinguish between:
  31. Describe the structure of the Earth. Write in paragraph:
  32. Write a note on the internal and external processes of Earth. Write in paragraph:…
  33. How are volcanoes classified based on the periodicity of their eruptions? Write in…
  34. Explain the effects of Volcanoes. Write in paragraph:
  35. Map Skill:On the given outline map of the world, mark the following:a. Pacific Ring of…
  36. Consider the various sources of information related to the Earth’s Interior. Classify the…
  37. Scientists use GPS to measure the rate of Tectonic Plate movements. Discuss. Higher Order…
  38. Life SkillsImagine that you feel tremors or shocks in your locality. What will be your…
  39. TRY ITAcross:1. The major elements of the mantle.2. Fractures that are formed when crustal…
Exercise
Question 1.

Choose the correct answer:

The is the rigid outer layer of the Earth.

A. Core

B. Mantle

C. Crust

D. Inner core


Answer:

The crust is the outer layer of the earth. It is on the crust where we live and plants are being planted. It ranges from 5km to 30km. The oceanic floor is much lower than the continental floor. The crust is classified into two continental crust and oceanic crust.


Question 2.

Choose the correct answer:

______ layer is made up of liquid iron

A. Inner core

B. Outer core

C. Mantle

D. Crust


Answer:

The core is the innermost and hottest layer of the Earth. It is composed of a mixture of nickel and iron. And then the innermost layer is the solid and outermost layer of the core is liquid. The presence of iron is higher in the core.


Question 3.

Choose the correct answer:

Magma is found in the _______

A. Crust

B. Mantle

C. Core

D. None of the above


Answer:

Mantle is the inner layer of the earth. Mantle is the next layer after the crust. Mantle is thick up to 2900km. The major element found inside the mantle is Silica (Si) and Magnesium (Mg). The upper layer of mantle will be solid whereas the lower layers will rock in molten form. The molten rock in the mantle is formed as magma.


Question 4.

Choose the correct answer:

Diastrophism is connected to

A. Volcanism

B. Earthquake

C. Tectonics

D. Fold/fault


Answer:

Diastrophic refers to deformation of the earth’s crust, more especially to folding and faulting. It can also be considered as a part of geotectonics. The word diastrophic refers to the Greek word which means twisting.


Question 5.

Choose the correct answer:

The movement of tectonic plates is induced by ______ energy.

A. Hydel

B. Thermal

C. Wave

D. Tidal


Answer:

The movement of the tectonic plates occurs when the there is thermal energy in the mantle. The plates float independently without influence on the mantle. Tectonic plates are of two types: minor plates and major plates. Mountain ranges are being occurred when there is a collision between these plates.


Question 6.

Choose the correct answer:

In the ancient period, Gondwana land moved towards ______ direction.

A. North

B. South

C. East

D. West


Answer:

Indian plate broke away from the Gondwana land around 140 million years ago. It slowly moved to the north and collided with Asia.


Question 7.

Choose the correct answer:

Many million years ago, India was a part of the supercontinent _____

A. Gondwana

B. Laurasia

C. Panthalassa

D. Pangea


Answer:

Indian plate broke away from the Gondwana land around 140 million years ago. It slowly moved to the north and collided with Asia.


Question 8.

Choose the correct answer:

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:

The movement of plates also creates stress and tension in the rocks, causing them to stretch and cracks. This will result in faulting.


Question 9.

Choose the correct answer:

_______refers to a bowl-shaped depression found at the top of the volcano.

A. Carter

B. Vent

C. Chamber

D. Volcanic Cone


Answer:

The volcano has the following major components. They are


• Chamber: A large pool liquid rock found beneath the crust


• Vents: It is an opening of the volcanic mountain, where the air and smoke are being out.


• Volcanic cone: it is the shape of the cone where magma is ejected from the vent.


• Carter: it is the bowl-shaped depression found at the top of the volcano


Question 10.

Choose the correct answer:

The point of origin of an Earthquake is called the _______

A. epicentre

B. focus

C. seismic wave

D. magnitude


Answer:

The focus is the point where the Earthquake originates. It is also known as Hypocenter and it generates a series of elastic waves.


Question 11.

Match the following



Answer:



1. Endogenetic process: 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. A volcanic eruption is a force that erupts form interior of the earth.


2. Mantle: Interior part beneath the crust is known as Mantle. It extends up to 2900 km thick. The major elements found in the mantle are Silica (Si) and Magnesium (Mg), hence it is popularly known as SIMA. In the upper part of the mantle the rock remains solid and inner part of the mantle the rock remains in liquid form.


3. Convergent boundaries: the boundaries of the plate move slowly and sink together. The sinking of plates through convergent boundaries are known as Subduction zone


4. Earthquake: Earthquake is the sudden vibration on the earth's crust which spreads in all directions as waves. A seismograph is a device used to measure the earthquake waves. It measures the seismic waves and the study related to seismic is known as seismology.


5. Composite volcano: It is also known as Starta volcano. It is conical volcano built in layers of hardened lava. It is commonly found in the Pacific Ocean.



Question 12.

Consider the given statements:

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:

Dormant volcano


The volcanoes which don't show any type of volcanic activity over a long period of time and it is known as a dormant volcano. Sometimes there can be a sudden explosion which is dangerous to the life that is near that mountain. Mt. Fuji in Japan is the example mountain for the dormant volcano.


Both Mt. Kilimanjaro and Mt. Tanzania is an extinct or dead volcano. They are said to be extinct because of the stopped eruption of the volcano.


Question 13.

Consider the given statements:

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. Statements & reason are true

b. Statements are true, the reason is false

c. Statement is false reason is true

d. Statement & reason are false


Answer:

Magma is filled under the earth's surface and it comes out of the fractures and vents. This is because the gas that comes out from the magma. This gas creates pressure on the rock inside and this leads to coming out of magma from the interior of the earth.


Question 14.

Consider the given statements:

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:

The continuous movement of the tectonic plates leads to the changes in the earth’s surface. The collision of these plates produces irregular surface and mountain ranges both on the land surface and the oceanic floor. This phenomenon is known as plate tectonics. The movement of the tectonic plates is due to the thermal energy from the mantle.


Question 15.

Answer the following in one or two sentences:

Write a brief note on the various spheres of the Earth.


Answer:

The planet Earth constitutes of many spheres. The spheres can be abiotic or biotic. The biotic spheres exist in earth is biosphere and abiotic spheres are lithosphere, atmosphere and hydrosphere.


The biosphere is the layer in which life exists. The human, plants and trees exist in the biosphere. Lithosphere, hydrosphere and atmosphere are the subsets of the biosphere.


The lithosphere is the solid outermost layer of the earth. It is the solid surface where we live, plant trees and constructs buildings.


Hydrosphere is the liquid part of the earth. It includes an ocean, sea, lake, etc. Life also exists in the hydrosphere such as fish and other water bodies.


The atmosphere is the layer in which the air is being available. Air is the most essential thing in life. The air that we breathe and carbon dioxide that plants consume are available in an atmospheric layer.



Question 16.

Answer the following in one or two sentences:

Mention the layers of the interior of the Earth.


Answer:

There are two types of layers for the planet earth namely outer and inner. The interior of the Earth has three different layers namely the crust, the mantle and the core.


The Crust


The crust is the outermost layer of the earth. It is the skin of the earth. It is the solid and rigid part of the earth. The plants and trees exist on the crust. It extends from 5km to 30km. The thickness of the crust is greater below the continents than the oceanic floor.


The Mantle


Interior part beneath the crust is known as Mantle. It extends up to 2900 km thick. The major elements found in the mantle are Silica (Si) and Magnesium (Mg), hence it is popularly known as SIMA. In the upper part of the mantle the rock remains solid and inner part of the mantle the rock remains in liquid form.


The Core


The core is the innermost layer of the earth which is just below the mantle. It is composed of minerals of Nickel (Ni) and Iron (Fe). Hence it is popularly known as NIFE. There are two types of core, namely solid outer core and Liquid inner core. Since there is a large amount of iron in the core, it is responsible for Earth's Gravitational Force.



Question 17.

Answer the following in one or two sentences:

What is pedosphere?


Answer:

Pedosphere is the part of lithosphere which is made up of soil and dust. It exists with the interface of all the spheres of the earth that is lithosphere, atmosphere, hydrosphere and biosphere. The biosphere is the layer in which life exists. The human, plants and trees exist in the biosphere. Lithosphere, hydrosphere and atmosphere are the subsets of the biosphere. The lithosphere is the solid outermost layer of the earth. Hydrosphere is the liquid part of the earth. It includes an ocean, sea, lake, etc. Life also exists in the hydrosphere such as fish and other water bodies. The atmosphere is the layer in which the air is being available. Air is the most essential thing in life. The air that we breathe and carbon dioxide that plants consume are available in an atmospheric layer.



Question 18.

Answer the following in one or two sentences:

Define Plate tectonics.


Answer:

The lithosphere is divided into number of huge slabs known as tectonic plates or lithosphere plates. This plate takes the movement independently over the mantle. The plates are classified into minor plates and major plates. When these plates float, they converge with other plates and therefore mountains and irregular surfaces are being created. This phenomenon takes place both in the continental floor and oceanic floor. This phenomena of movement of plate is known as ‘plate tectonics'.



Question 19.

Answer the following in one or two sentences:

Write a note on Fold and fault?


Answer:

The folding happens because of the lateral compression on plates. This causes the movement of plates upwards and downwards. This is called folding and when mountains are formed due to this process they are called as Fold Mountains. Himalaya and Alps are one such fold mountains and they are lofty mountains created by the process of folding.


The movement of plates also creates stress and tension in the rocks, causing them to stretch and cracks. This process is called faulting. The Great Rift Valley can be an example of the process of faulting.



Question 20.

Answer the following in one or two sentences:

What is a Tsunami?


Answer:

The word Tsunami is originated from the Japanese word which means the Harbour waves. The Tsunami is being created when there large seismic waves under the sea caused by an earthquake, submarine explosion and landslides. These waves can travel more than the speed of 500km per hr. The waves reach the height of 15meter which causes major disaster in coastal areas. On December 4, 2008, India has been faced a major disaster due to the tsunami. This was caused in the Indian Ocean due submerge of Australian plate and Eurasian Plate. The earthquake undersea measured at 9 Richter scale.



Question 21.

Answer the following in one or two sentences:

What is a Volcano? Mention its major components.


Answer:

A volcano is a place where gases, ashes and/or molten rock material i.e., lava escape to the ground. The layer below the solid crust is a mantle. It has a higher density than that of the crust. It is from this that the molten rock materials find their way to the surface. The material in the upper mantle portion is called magma. When the magma is out from the volcanic mountain then it is termed as Lava. It may also happen when the plates move apart.


The volcano has the following major components. They are


• Chamber: A large pool liquid rock found beneath the crust


• Vents: It is an opening of the volcanic mountain, where the air and smoke are being out.


• Volcanic cone: it is the shape of the cone where magma is ejected from the vent.


• Carter: it is the bowl-shaped depression found at the top of the volcano



Question 22.

Answer the following in one or two sentences:

What is an Earthquake and how it occurs?


Answer:

Earthquake is caused by the sudden vibration under the earth crust. The vibration spreads outward in all the direction as waves from the source of the disturbance. The point at which the earthquake starts is called focus (hypocenter) which creates a series of waves. The epicentre is a point on earth surface which lies above the point of focus, the effect of the earthquake is mainly caused by the epicentre. An earthquake occurs due to release of energy along a fault. A fault is a sharp break in between the crustal rocks .rocks and fault to move in opposite direction.


It occurs from the focus, where the vibration starts and extends up to the Epicentre. It makes the shaking in above the crust and this makes the buildings also shake.



Question 23.

Answer the following in one or two sentences:

What are seismic waves and mention its types?


Answer:

Seismic waves are generally generated when there is an earthquake on the surface. Earthquake creates seismic waves. The seismic waves are the speed and force of the waves at which it depends on the medium at which it's travel. For seismic waves there are mainly three types of waves:


a. primary or p- waves


b. secondary or s- waves


c. surface waves or L- waves


• Primary waves or P-waves


The primary waves are popularly known as P-waves. P- waves are the fastest waves of all earthquake and it's the to reach the epicentre and it travels through solid, liquid, gases and the average velocity of P- waves are 5.3km per second to 10.6 km per second.


• Secondary waves or S- waves


This travels only through the solids. These waves shake the ground in the perpendicular direction. The average velocity of S- waves is 1km per second to 8km per second.


• Surface waves or L- waves


Are similar to P- waves but they travel through ground surface. Compare to other waves L- waves are very slow and it's most destructive. The average velocity of these waves is 1km per second to 5 km per second.



Question 24.

Answer the following in one or two sentences:

Write about the Pacific Ring of fire.


Answer:

The Pacific Ring of Fire is the arc-like structure throughout the boundaries of Pacific Ocean where a number of volcanic active zones are found. Most earthquakes, volcanoes and tsunamis are observed in these regions. These are the areas where the Pacific plates specifically meet each other. This ring of fire is both seismically and volcanically active zone in the world. Tsunamis are frequently observed in Pacific Ring of Fire, particularly found in along the coast of Alaska, Japan, Philippines, and other islands of Southeast Asia, Indonesia, Malaysia, Myanmar, Sri Lanka, and India etc.



Question 25.

Give Reasons for the following:

SIAL floats over SIMA.


Answer:

The majority of the earth’s surface comprises of SIAL which is the combination of Silica and Aluminium. This SIAL is found in the crust layer of the earth. The lower layer of the earth’s crust that is mantle comprises of SIMA. The SIMA is the abbreviation used to describe the minerals of Silicon and Magnesium.


The content of Silica in SIAL is more than that of SIMA. This makes the SIAL less dense than that of SIMA. It is the density of the minerals makes the floating and submerges of the elements.



Question 26.

Give Reasons for the following:

Igneous rocks are also called Primary Rocks or Mother rocks.


Answer:

Igneous rock is derived from the Latin word called ‘Ingis’ which means Fire. Igneous rock is popularly known as primary rocks or mother rocks because all other rocks are directly or indirectly formed from Lava and Magma. Lava and Magma are the materials which are found under the earth surface. When this magma reaches the earth surfaces it is called lava. When this lava cools down and solidifications on the surface are called igneous rocks. The best examples of igneous rocks are Granite and Basalt. These igneous rocks are highly used for the construction works and laying of roads.


Igneous rocks are broadly classified on the basis of texture. The texture is highly depending upon the size and other physical condition of materials. The intermediate cooling condition of the lava defines the texture and shape of the rocks. Other most popular examples of igneous rocks are gabbros, pegmatite, volcanic breccias and tuff.



Question 27.

Distinguish between:

Core and crust.


Answer:




Question 28.

Distinguish between:

Epicentre and Hypocentre


Answer:




Question 29.

Distinguish between:

Primary waves and Secondary waves.


Answer:




Question 30.

Distinguish between:

Shield volcano and volcanic Dome.


Answer:




Question 31.

Write in paragraph:

Describe the structure of the Earth.


Answer:

The structure of the inner and outer part of the earth is totally different. The interior structure of the earth is divided into three major layers: the crust, the mantle and the core. Each layer is rich in different elements and minerals.


• The Crust


It is the outermost layer of the earth. It is fragile in nature. The thickness of the crust varies under the oceanic and continental areas. Oceanic crust is thinner as compared to the continental crust. The thickness of the crust varies from 5km to 30km in which, the mean thickness of oceanic crust is 5 km whereas that of the continental is around 30 km. The continental crust is thicker in the areas of major mountain areas. It is as much as 70 km thick in the Himalayan region. The rocks found in oceanic crust are rich in basalt.


• The mantle


It is the layer which lies above the crust. The mantle extends up to the thickness of 2900km. Mantle is the main source for the volcanic eruption because of the rocks present in the molten form. The major elements found in the mantle are Silica (Si) and Magnesium (Mg), hence it is popularly known as SIMA. In the upper part of the mantle the rock remains solid and inner part of the mantle the rock remains in liquid form. The crust and the uppermost part of the mantle are called lithosphere. Its thickness ranges from 10-200 km.


• The core


The core is the innermost and hottest layer in the earth. It lies just beneath the mantle. It is composed of minerals of Nickel (Ni) and Iron (Fe). Hence it is popularly known as NIFE. There are two types of core, namely solid outer core and Liquid inner core. Since there is a large amount of iron in the core, it is responsible for Earth's Gravitational Force.



Question 32.

Write in paragraph:

Write a note on the internal and external processes of Earth.


Answer:

The forces acts form the interior of the earth to the earth's surface is known as an internal or endogenetic process. These forces are responsible for creating the landscape and topographic relief. Internal process ejects heat from the interior of the earth to the surface. Internal radioactivity is the principal source of power for this process. The plate tectonics, earthquakes, volcanoes are examples of the internal process.


The forced act on the earth's surface due to the natural agents such as water, glacier, wind, waves etc. is called an external processor exogenetic process. This process tears the landscape down into relatively low elevated plains.



Question 33.

Write in paragraph:

How are volcanoes classified based on the periodicity of their eruptions?


Answer:

A volcano is a place where gases, ashes and/or molten rock material i.e., lava escape to the ground. The layer below the solid crust is a mantle. It has a higher density than that of the crust. It is from this that the molten rock materials find their way to the surface. The material in the upper mantle portion is called magma. When the magma is out from the volcanic mountain then it is termed as Lava. It may also happen when the plates move apart.


Volcanoes are classified into three on the basis of periodicity.


i. Active volcano


ii. Dormant volcano


iii. Extent volcano


• Active volcano


These are volcanoes which continuously eject the lava, gaseous and fragmented minerals. These types of volcanoes are found in Mount St. Helens in the United States.


• Dormant volcano


The volcanoes which don't show any type of volcanic activity over a long period of time and it is known as a dormant volcano. Sometimes there can be a sudden explosion which is dangerous to the life that is near that mountain. Mt. Fuji in Japan is the and


• Extent volcano


These are volcanoes which have permanently stopped ejecting lava. In these types, volcanoes have permanently extinct. These are also known as a dead volcano.


Mt. Kilimanjaro and Tanzania is the extent volcano.



Question 34.

Write in paragraph:

Explain the effects of Volcanoes.


Answer:

There are two different effects that are emerged due to the volcanic eruption. They are


i. Constructive effects


ii. Destructive effects


• Constructive effects


The volcanic eruption increases the soil fertility which promotes agricultural activities. Geothermal energy is produced when the volcanic lava in produced. Many dormant and active volcanoes are attracted to the tourist spots. Building materials are being created by the volcanic materials.


• Destructive effects


Volcanic eruptions which cause earthquakes, fast flood, mudslide and rock fall. Lava which travels very far and they destroy many lives and bury them into the lava. Breathing problems and skin irritation take place due to the ash and fog of the volcano. Volcanic eruptions also create changes in weather conditions and create problems in transportations around the volcanic regions.



Question 35.

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:


• NEPAL and TURKEY are the two earthquake zone in the world


• Mount St. Helens And Mount Merapi are the active volcanic zones.



Question 36.

Higher Order Thinking Questions (Hots)

Consider the various sources of information related to the Earth’s Interior. Classify the above as DIRECT & INDIRECT sources of information. Give reasons



Answer:


Explanation


• Direct sources


The direct sources include molten magma behind the rocks. When the mining and drilling activities take place the there will be chances for the volcanic eruption.


• Indirect sources


The meteoroid fall on the earth creates the waves in the earth. These measure the seismic activity on the earth surface.


A large amount of iron in the core is responsible for gravitational force. The earth’s rotation in its own axis and the liquid outer core spins over the solid inner core and generates the Earth’s magnetic field.



Question 37.

Higher Order Thinking Questions (Hots)

Scientists use GPS to measure the rate of Tectonic Plate movements. Discuss.


Answer:

The scientist usually uses GPS to measure the Tectonic Plate movements. Each plate on the earth rotates the ‘pole' and each plate has different speed of GPS station.GPS station which records the exact distance between the satellite and ground station. By recording the time it takes for the GPS ground stations to move a given distance, therefore the scienti8st can measure the exact speed at which tectonic plate move.



Question 38.

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:

The feeling of tremors and shocks may be due to the earthquake. Earthquake causes the tremors or shocks on the surface. When we indulge in saving lives there many much does and don'ts that are to be considered before indulging in the process.


Do’s


• Drop to the ground


Make all the people cover themselves under the table or furniture. We must hold on until the shaking stops. If there is not that much cover, then cover your face and sit in the corner of the building.


• Stay from the glass, windows, outside doors and walls and anything that would fall.


• Stay in bed if nothing is possible and protect your head with a pillow. Try to move to the safest place.


• Do not use elevators. Be aware that electricity may be interrupted and fire alarm may turn off.


• Move to the free land if possible. Try to move to the nearest ground where there are no buildings or electrical posts.


• Avoid stopping the vehicle under the building and do not stay in the car if you are under the building, trees, utility wires etc.


• Proceed cautiously once the earthquake has stopped. Avoid roads and bridges which have been damaged by the earthquake.


Don’ts


• Do not run here and there while there is shaking on the ground. To be in the safer side and away from the danger zone, stay inside if you're inside and stay outside if you're outside.


• Do not stand in a doorway: Earthquake collapses the building then doors and windows collapse. If we stand beside the door, it will be a dangerous place while earthquake.


• Stay away from the electrical wiring. This electrical wiring creates the circuit collapse in the affected area.


• Don't be panic and be in chaos, calm and composed. Panicking makes further problems among the people.


• Don't be in low-level areas and under any shelter for building or trees. Always try to be in high-level areas, these make a better safety for the people.



Question 39.

TRY IT



Across:

1. The major elements of the mantle.

2. Fractures that are formed when crustal rocks are displaced.

3. These waves are the most destructive seismic waves.

4. The other name of Core.

5. These waves are generated when Earthquake occurs.

Down:

6. This occurs due to endogenic movements.

7. Bowl-shaped depression found at the top of a volcano.

Up:

8. The point on the Earth's surface where the Earthquake is measured.

9. Large seismically generated sea waves.


Answer:

Across:


1. The major elements found in the mantle are Silica (Si) and Magnesium (Mg), hence it is popularly known as SIMA


2. Due to the earthquake and other tectonic shifts, fractures are being formed in the rocks. The fault is the fracture between crustal rocks.


3. L-waves are the most destructive seismic waves compared to the other P-waves and S-waves.


4. The centre of the earth is known as the core. Therefore, is also known as the centre.


5. Seismic waves are generally generated when there is an earthquake on the surface. Earthquake creates seismic waves


Down


6. Landslides are the major occurrence due to the endogenic movement of the earth.


7. Carter: it is the bowl-shaped depression found at the top of the volcano


Up


8. Epicentre: Epicentre is a point on earth surface which lies above the point of focus, the effect of the earthquake is mainly caused by the epicentre


9. Tsunami: it is the word derived from the Japanese word which means harbour waves. It caused due to the large seismic waves under the sea.