Volcanoes: ICSE Class 9 Geography solution

Summary

The earth has forces inside it called endogenic forces. These forces can cause slow changes or sudden movements. Volcanoes are a result of these sudden movements. A volcano is an opening, or vent, in the earth’s crust. Fiery hot melted rock, called magma, erupts from this opening.

Several things cause volcanic eruptions. One cause is the heat and pressure deep inside the earth. Temperature and pressure increase as you go towards the earth’s center. Rocks don’t let heat escape easily. So, the heat melts rocks and builds up great pressure. This pressure forces the hot material to find a way out through cracks. Another major cause is plate tectonics. The earth’s surface is made of large moving pieces called plates. When these plates move, they can slide past or hit each other. This creates weak spots and faults, especially at their edges. Hot magma then pushes through these weaknesses, causing an eruption. Deep beneath the earth’s crust, magma can melt rocks to create a large space called a magma chamber. Fresh magma keeps filling this chamber, increasing pressure. This pressure pushes the magma upwards to the surface, often along plate boundaries.

When a volcano erupts, it releases several things. The molten rock inside the earth is magma. When it reaches the surface, it is called lava. Steam is the most common gas released. Other gases include hydrogen sulphide, sulphur dioxide, carbon dioxide, and hydrogen. Solid pieces of rock, called pyroclasts, are also thrown out. Fine particles are dust, and small stone-sized pieces are lapilli. Larger ejected pieces are called bombs.

A volcano has a main opening called a vent, through which lava flows. As erupted material cools and hardens around the vent, it forms a cone-shaped hill known as a volcanic cone.

Volcanoes are grouped into three types based on how often they erupt. Active volcanoes are currently erupting or have erupted recently. Mount Etna is an example. Dormant volcanoes have not erupted for a long time but could erupt again. They are like ‘sleeping volcanoes’. Mount Kilimanjaro is an example. Extinct volcanoes have not erupted in recent history and are not expected to erupt again, like Mount Kenya.

Volcanic eruptions have both good and bad effects. Good effects include creating new landforms. Lava flows can form volcanic plateaus, like the Deccan Plateau in India. Ejected material can build volcanic mountains, such as Mount Fuji. Volcanic plains are formed by widespread lava flooding. Sometimes, a volcano’s top collapses, forming a large depression called a caldera, which can fill with water to become a caldera lake. Underground water heated by magma can create hot springs, which are rich in minerals and good for health. Geysers are fountains of hot water and steam. Volcanic ash also makes soil fertile for farming. Heat from volcanic areas can be used for geothermal energy. The dramatic scenery also attracts tourists.

Bad effects include the destruction of life and property by hot lava, ash, and dust. Farmlands can be buried under ash. Eruptions can cause heavy rains, leading to floods and landslides. Poisonous gases pollute the air. Volcanoes in the ocean can cause large sea waves called tsunamis.

Most volcanoes are found in specific areas. The Circum-Pacific Belt, also called the Pacific Ring of Fire, has over 80% of active volcanoes. It is called a “Ring of Fire” because many volcanoes are located in a ring shape around the Pacific Ocean. Another area is the Mid-world Mountain Belt, which includes volcanoes like Mount Vesuvius.

Textbook solutions (Morning Star/Total)

Multiple-Choice Questions

1. The forces arising from the interior of the earth:

(a) Endogenic forces
(b) Exogenic forces
(c) Platonic forces
(d) Interior forces

Answer: (a) Endogenic forces

2. A vent in the earth’s crust from which fiery hot magma erupts from the earth’s interior:

(a) Plate
(b) Tectonics
(c) Volcano
(d) Vent

Answer: (c) Volcano

3. Which of the following is NOT a cause of volcanic eruptions?

(a) Heat and pressure outside the earth
(b) Plate Tectonics
(c) Magma chamber
(d) Heat and pressure inside the earth

Answer: (a) Heat and pressure outside the earth

4. Which amongst the following is NOT a product of volcano?

(a) Magma
(b) Lava
(c) Solid Matter
(d) Vent

Answer: (d) Vent

5. A huge magma chamber which is joined to the earth’s surface by a conduit under a volcano:

(a) Volcano
(b) Vent
(c) Dormant volcano
(d) Volcanic vent

Answer: (d) Volcanic vent

6. The lava flows out through an opening in the earth’s crust called:

(a) Vent
(b) Volcano
(c) Volcanic vent
(d) Plate tectonics

Answer: (a) Vent

7. During repeated eruptions the summit of a volcano may be blown up leaving a large depression called:

(a) Caldera
(b) Hot springs
(c) Geysers
(d) Circum belt

Answer: (a) Caldera

8. _______ is a fountain of hot water and steam that escapes when underground water comes into contact with hot volcanic rocks.

(a) Caldera
(b) Hot springs
(c) Geysers
(d) Volcano

Answer: (c) Geysers

9. Which of the following is incorrect?

(a) Extinct Volcano : Mt. Kenya
(b) Dormant Volcano : Mt. Kilimanjaro
(c) Extinct Volcano : Mt. Etna
(d) Active Volcano : Mt. Stromboli

Answer: (c) Extinct Volcano : Mt. Etna

10. Which of the following is NOT a constructive effect of volcanoes?

(a) Landform formation
(b) Tsunami
(c) Geothermal energy
(d) Tourism

Answer: (b) Tsunami

11. The volcanoes that occur near Earthquake belts and tectonic plate boundaries:

(a) Caldera
(b) Geysers
(c) Pacific ring of fire
(d) Mid-world mountain belt

Answer: (c) Pacific ring of fire

12. Mt. Vesuvius, Mt. Etna are located in the:

(a) Circum Pacific belt
(b) Mid-world Mountain Belt
(c) Pacific Ring of fire
(d) None of the above

Answer: (b) Mid-world Mountain Belt

13. _______ are also known as Thermal Springs.

(a) Hot springs
(b) Geysers
(c) Volcano
(d) Caldera

Answer: (a) Hot springs

14. Among Circum Pacific Belt, _______ active volcanoes in Indonesia are included.

(a) 100
(b) 40
(c) 70
(d) 40

Answer: (c) 70

Short Answer Questions

1. What is a volcano? Give one example.

Answer: A volcano is a vent in the earth’s crust from which fiery hot magma erupts from the earth’s interior. An example of an active volcano is Mt. Stromboli in Italy.

2. What is the difference between magma and lava?

Answer: The molten rock material inside the earth is known as magma. When magma reaches the surface of the earth, it is known as lava.

3. Give one example each of an active volcano and a dormant volcano.

Answer: An example of an active volcano is Mt. Etna in Italy. An example of a dormant volcano is Mt. Kilimanjaro of Africa.

4. What is the difference between dormant volcano and an extinct volcano?

Answer: Dormant volcanoes are those that have not erupted in recent historical period; they are regarded as ‘sleeping volcanoes’ and may become active at any time. In contrast, extinct volcanoes are the types which have not erupted in the present geological period and are not likely to become active again.

5. What is the magma chamber of a volcano? State the products erupted by a volcano.

Answer: A magma chamber is a huge chamber or reservoir beneath major volcanoes, created when molten material under the earth’s crust melts weak rocks. Fresh magma continues to pour inside this chamber, which is joined to the earth’s surface by a conduit known as a volcanic vent.

A volcano erupts a number of products like steam, gases, molten rock, dust, ashes and other liquid and solid matter. These include:

(i) Magma and Lava: Lava is the molten rock material that reaches the surface. Steam is the most abundant gas, and other gases include hydrogen sulphide, sulphur dioxide, carbon dioxide, and hydrogen.
(ii) Solid Matter: These are rock pieces known as pyroclasts. Fine particles are called dust, small stone-sized particles are called lapilli, and violent eruptions eject larger materials known as bombs.

6. Name two types of landforms made by volcanoes. Give an example of each type.

Answer: Two types of landforms made by volcanoes are:

(a) Volcanic Plateaus: These are derived from lava which flows from volcanic eruptions. An example is the Plateau of Peninsular India, especially the north western Deccan.
(b) Volcanic Mountains: These mountains are built from material ejected from the fissures in the earth’s crust. An example is Mt. Fuji in Japan.

7. What is the Pacific Ring of Fire? Why is it so called?

Answer: The Circum Pacific Belt is also called the Pacific Ring of Fire. It is so called because over 80% of the total number of active volcanoes are concentrated in this region.

Structured Questions

1. (a) Describe the two causes of volcanic eruptions.

Answer: The main causes of volcanic eruptions are the following:

(i) Heat and Pressure inside the Earth: Temperature and pressure both increase from the surface towards the centre of the earth. Rocks are bad conductors of heat. So the earth’s heat does not escape on its own. Instead, it melts the rocks and builds up great pressure. The pressure forces the heat to find an escape route through fissures and cracks in the rocks.
(ii) Plate Tectonics: Most volcanic eruptions take place near plate margins. The earth’s crust is made up of a series of movable plates. When these plates slide past each other or collide against each other due to intense heat inside the earth’s core, their edges produce faults along the lines of weakness. It is along these plate boundaries that the crust is weakened and through which the hot magma gushes out leading to volcanic eruption.

1. (b) Describe the two types of volcanoes, giving an example of each type.

Answer: Two types of volcanoes are:

(i) Active Volcanoes: These are the volcanoes which are presently in active state and have erupted in the recent past. There are at present about 500 known active volcanoes. About 20 of these volcanoes may erupt at any time. A few of these volcanoes are also in a state of permanent eruption. Some of the examples of active volcanoes are Mt. Stromboli and Mt. Etna in Italy; Pinatubo in Philippines and Mauna Loa in Hawaii.
(ii) Dormant Volcanoes: These volcanoes have not erupted in recent historical period. They are regarded as ‘sleeping volcanoes’ and may become active at any time. Examples of dormant volcanoes are Mt. Kilimanjaro of Africa. Mt. Vesuvius, though regarded as active, is actually rated as dormant because there has been no major eruption since 1944.

1. (c) Give a geographical reason for each of the following:

(i) Many volcanoes are found along plate boundaries.
(ii) Volcanic mountains are the most diverse mountains in the world.
(iii) Hot springs have medicinal properties to cure skin diseases.

Answer: (i) Many volcanoes are found along plate boundaries because most volcanic eruptions take place near plate margins. When these plates slide past each other or collide against each other due to intense heat inside the earth’s core, their edges produce faults along the lines of weakness. It is along these plate boundaries that the crust is weakened and through which the hot magma gushes out leading to volcanic eruption. Also, magma contains silicate material, gases and water vapours, so the pressure always acts vertically upwards. Once a route is found it rises to the surface, and this is why many volcanoes are found along plate boundaries.

(ii) Volcanic mountains are the most diverse mountains in the world because there are great differences in volcanic eruptions as well as the materials they throw up.

(iii) Hot springs have medicinal properties to cure skin diseases because hot springs are a rich source of sulphur, and they are considered good for health specially for curing certain skin diseases.

1. (d) Draw a well labelled diagram showing the different parts of a volcano and the products erupted by it.

Answer: See Fig. 7.2 (Total History/Morning Star) or click here.

2. (a) Explain briefly the landforms created by volcanoes on the surface of the earth.

Answer: Numerous types of landforms are created due to cooling and solidification of magma below the earth’s surface and lava on the earth’s surface. The landforms created on earth’s surface are called Extrusive Landforms. These include:

(a) Volcanic Plateaus: These are derived from lava which flows from volcanic eruptions. The Plateau of Peninsular India, especially the north western Deccan, is an example of lava plateau.
(b) Volcanic Mountains: These mountains are built from material ejected from the fissures in the earth’s crust. Volcanic mountains like Mauna Loa in Hawaii rise 9 km from the ocean floor.
(c) Volcanic Plains: These plains are vast and smooth formed by extensive volcanic flooding from volcanic centres. The Western Victorian Plains in Victoria, Australia are the finest examples of Volcanic Plains.
(d) Caldera Lake: During repeated eruptions the summit of a volcano may be blown up. In its place a large depression called caldera is formed. This depression eventually gets filled with water and forms a lake. For example, Crater Lake in the USA is a Caldera lake.

2. (b) Write any three destructive effects of volcanoes.

Answer: Three destructive effects of volcanoes are the following:

(i) When the volcanoes erupt they destroy life and property. The hot lava together with ash and dust destroy not only human beings, but also animals as well as plant life.
(ii) Agricultural fields are covered with layers of volcanic ash and dust making them unsuitable for cultivation.
(iii) Huge clouds are formed after the eruption of volcanoes causing heavy rains which result in floods and landslides.

2. (c) Explain the following terms:

(i) Volcanic Cone
(ii) Caldera
(iii) Geyser

Answer: (i) Volcanic Cone: The erupted fluid material being hot collects around the vent and begins to cool gradually and solidifies. The accumulation of material around the vent gives to the volcano its typical cone-like shape known as the Volcanic cone.

(ii) Caldera: During repeated eruptions the summit of a volcano may be blown up. In its place a large depression called caldera is formed. These are generally formed when the magma chamber is no longer able to emit sufficient magma and this results in the collapse of a cone either partly or wholly.

(iii) Geyser: A geyser is a fountain of hot water and steam that escapes when underground water comes into contact with hot volcanic rocks.

2. (d) Describe world distribution of volcanoes.

Answer: The important volcanic zones of the world are:

Circum Pacific Belt: The Volcanoes occur near Earthquake belts around the young fold mountains. The Circum Pacific Belt is also called the Pacific Ring of Fire because over 80% of the total number of active volcanoes are concentrated in this region. Among these are included 40 active volcanoes in Andes, over 100 in the Philippines, 70 in Indonesia and 40 in Japan.

Mid-world Mountain Belt: Mt. Vesuvius, Mt. Etna and Mt. Stromboli, the famous active volcanoes, are located in the Mid-world Mountain Belt. The only active volcano in India, in Andaman and Nicobar Islands, is also located in this belt. The Hawaiian Islands, Canary Islands, Mt. Kenya are all in the Mid-world Mountain Belt.

Thinking Skills

1. Imagine that you had gone for a holiday and an extinct volcano erupted. List the consequences.

Answer: If an extinct volcano erupted during a holiday, the consequences would be unexpected and disastrous. There would likely be significant loss of life and damage to property, as neither residents nor tourists would be prepared for such an event. The eruption would destroy local vegetation and wildlife, while the ash and lava would cover the surrounding areas, making them uninhabitable. Transport and communication networks would be disrupted, leaving people stranded or unable to contact emergency services. The eruption would release harmful gases, polluting the air and affecting both health and the environment. Farmlands would be buried under ash and debris, ruining crops and making the soil infertile. The psychological impact would also be considerable, with widespread panic and fear among those affected.

2. Suppose you are living in an area known for volcanic eruptions. One day, when you were sitting in your balcony, you suddenly noticed a volcano erupting at a distance. State what happened thereafter.

Answer: As I sat on the balcony, I noticed thick smoke and ash billowing from the volcano, followed by a loud, thunderous explosion. Lava began to flow down its slopes, setting nearby trees and structures on fire. The sky quickly darkened as ash clouds spread across the area, reducing visibility and causing breathing difficulties. Emergency sirens wailed, and announcements urged people to evacuate immediately. I gathered essential belongings and joined others trying to leave the area. Roads were congested with vehicles and people on foot, all moving away from the danger zone. Soon after, heavy rain triggered by the ash clouds led to flooding and landslides, worsening the situation. We were relocated to a temporary shelter where food and medical aid were provided. Though the eruption eventually subsided, the damage it left behind was severe, and the area remained unsafe for days.

Map Work/Project

1. Using your knowledge of chemistry make a model of a volcano to study the extent of damage that can be caused by a volcanic eruption. Extrapolate your calculations to predict the energy released during the last few volcanic eruptions.

Answer: Do it yourself. Here are the instructions:

Collect materials: baking soda, vinegar, dish soap, red food colouring (optional), empty plastic bottle, clay or paper mâché, a tray or cardboard base.
Fix the bottle on the base and build a volcano cone around it using clay or paper mâché. Leave the bottle’s mouth open.
Mix 2–3 tablespoons of baking soda with a few drops of dish soap and food colouring. Pour it into the bottle.
In a cup, mix about 100 ml of vinegar. When ready, pour it into the bottle. The eruption will happen due to the chemical reaction between vinegar (acid) and baking soda (base), creating carbon dioxide gas and foamy lava.
Record the amount of vinegar and baking soda used. Increase quantities to test the extent of “damage” by observing the spread and height of the eruption. Place small objects around the volcano to study impact zones.
Calculate energy released (in a fun, comparative way) by comparing with real-life eruptions like that of Mount Pinatubo in 1991 or Taal in 2020. You may use simple proportional reasoning to guess how many times stronger a real eruption would be.

2. Recently there was a news article regarding the closure of Manila’s International airport following a major volcanic eruption of the Taal Volcano. On the map of the world locate the Taal Volcano. What inference do you draw from the location of the volcano? Correlate your findings with news articles of the eruption. Make a list of potential eruption prone volcanoes that could cause closure of international airports in other countries. Mark them on an outline map of the world.

Answer: Do it yourself. Here are the instructions:

Locate the Philippines on a world map. Taal Volcano is in Luzon, about 60 km south of Manila. Mark its position clearly.
Understand that the Philippines lies on the “Pacific Ring of Fire,” where many active volcanoes are found. The location of Taal near a tectonic plate boundary explains its frequent activity.
Search news articles online about the Taal eruption (e.g., January 2020 or more recent events) to understand how ash clouds can disrupt air travel.
Make a list of other active volcanoes near international airports that could cause flight disruptions:
- Mount Etna (Italy – near Catania Airport)
- Mount Fuji (Japan – near Tokyo)
- Mount Merapi (Indonesia – near Yogyakarta)
- Mount Agung (Bali – near Denpasar Airport)
- Mount Kilauea (Hawaii – near Hilo Airport)
- Mount Popocatépetl (Mexico – near Mexico City)
- Eyjafjallajökull (Iceland – disrupted European flights in 2010)
Mark these volcanoes on a blank world map. You can print one or draw a rough sketch.

Extras

Additional MCQs

1. Which forces are called endogenic forces?

A. Forces arising from earth’s interior
B. Forces by atmosphere
C. Forces by ocean currents
D. Forces by magnetic field

Answer: A. Forces arising from earth’s interior

2. Which type of endogenic force includes volcanic eruptions?

A. Sudden movements
B. Diastrophic movements
C. Erosion processes
D. Deposition processes

Answer: A. Sudden movements

3. A vent in the earth’s crust through which magma erupts is called:

A. Volcano
B. Earthquake
C. Geyser
D. Fault

Answer: A. Volcano

4. What causes magma to find an escape route through fissures?

A. High temperature and pressure
B. Low gravity
C. Magnetic fields
D. Ocean tides

Answer: A. High temperature and pressure

5. Most volcanic eruptions occur near:

A. Plate boundaries
B. River valleys
C. Dune fields
D. Plains

Answer: A. Plate boundaries

6. What is molten rock beneath the earth’s crust called?

A. Magma
B. Lava
C. Tephra
D. Basalt

Answer: A. Magma

7. When magma reaches the surface it is called:

A. Lava
B. Magma
C. Pyroclast
D. Tephra

Answer: A. Lava

8. The most abundant gas emitted during an eruption is:

A. Steam
B. Carbon dioxide
C. Sulphur dioxide
D. Hydrogen

Answer: A. Steam

9. Small stone-sized particles ejected by a volcano are called:

A. Lapilli
B. Ash
C. Bombs
D. Blocks

Answer: A. Lapilli

10. The opening through which lava flows out is known as:

A. Vent
B. Fissure
C. Ridge
D. Dome

Answer: A. Vent

11. What landform is created by cooled lava around a vent?

A. Volcanic cone
B. Crater lake
C. Lava plateau
D. Caldera

Answer: A. Volcanic cone

12. Volcanoes that have not erupted recently but may erupt again are termed:

A. Dormant
B. Active
C. Extinct
D. Erupted

Answer: A. Dormant

13. Which volcano has been dormant since its last major eruption in 1944?

A. Mt Vesuvius
B. Mt Etna
C. Mt Stromboli
D. Mt Kilimanjaro

Answer: A. Mt Vesuvius

14. Approximately how many active volcanoes are known worldwide?

A. 500
B. 20
C. 1000
D. 100

Answer: A. 500

15. Which volcano rises about 9 km from the ocean floor?

A. Mauna Loa
B. Mt Fuji
C. Mt Kilimanjaro
D. Pinatubo

Answer: A. Mauna Loa

16. Smooth, flat areas formed by extensive lava flooding are called:

A. Volcanic plains
B. Volcanic mountains
C. Volcanic cones
D. Lava domes

Answer: A. Volcanic plains

17. Which Indian region is an example of a lava plateau?

A. North-western Deccan
B. Eastern Ghats
C. Western Ghats
D. Brahmaputra valley

Answer: A. North-western Deccan

18. What name is given to a collapse depression that fills with water?

A. Caldera lake
B. Volcanic crater
C. Lava cave
D. Pit lake

Answer: A. Caldera lake

19. Springs of hot water emerging from volcanic areas are called:

A. Hot springs
B. Cool springs
C. Mineral springs
D. Artesian springs

Answer: A. Hot springs

20. Which geyser is famous for its regular eruptions in Yellowstone?

A. Old Faithful
B. Great Fountain
C. Castle Geyser
D. Steamboat

Answer: A. Old Faithful

21. Over 80% of active volcanoes are concentrated in the:

A. Pacific Ring of Fire
B. Mid-Atlantic Ridge
C. Himalayan Belt
D. African Rift

Answer: A. Pacific Ring of Fire

22. Mt Etna and Mt Vesuvius are part of the:

A. Mid-world Mountain Belt
B. Pacific Ring of Fire
C. Andes Belt
D. East African Rift

Answer: A. Mid-world Mountain Belt

23. Which plateau in South Africa is formed by volcanic activity?

A. South African plateau
B. Ethiopian plateau
C. Deccan plateau
D. Columbia Plateau

Answer: A. South African plateau

24. What energy source is abundant in volcanic regions?

A. Geothermal
B. Solar
C. Wind
D. Hydroelectric

Answer: A. Geothermal

25. Explosive eruptions of ocean island volcanoes can trigger:

A. Tsunami
B. Cyclones
C. Monsoons
D. Earthquakes

Answer: A. Tsunami

26. Which gas from volcanoes contributes to acid rain formation?

A. Sulphur dioxide
B. Carbon dioxide
C. Hydrogen
D. Nitrogen

Answer: A. Sulphur dioxide

27. Fragments of rock produced by volcanic eruptions are called:

A. Pyroclasts
B. Lapilli
C. Bombs
D. Ash

Answer: A. Pyroclasts

28. What term refers to fine volcanic dust?

A. Ash
B. Lapilli
C. Bombs
D. Blocks

Answer: A. Ash

29. Which of these is NOT a volcanic landform?

A. River valley
B. Lava plateau
C. Caldera
D. Volcanic cone

Answer: A. River valley

30. Which feature connects a magma chamber to the earth’s surface?

A. Central conduit
B. Lava flow
C. Pyroclastic flow
D. Fumarole

Answer: A. Central conduit

31. What material builds up to form volcanic plateaus?

A. Lava flows
B. Ash clouds
C. Pyroclastic bombs
D. Gases

Answer: A. Lava flows

32. Which volcanic mountain in the Philippines is known for its symmetrical cone?

A. Mt Mayon
B. Mt Pinatubo
C. Mt Merapi
D. Mt Cotopaxi

Answer: A. Mt Mayon

33. Which Indonesian volcano listed is part of the Circum Pacific Belt?

A. Mt Merapi
B. Mt Kenya
C. Mt Aconcagua
D. Mt Kilimanjaro

Answer: A. Mt Merapi

34. What destructive effect can bury agricultural fields under ash?

A. Dust fall
B. Lava flow
C. Thermal springs
D. Hot lava

Answer: A. Dust fall

35. Which poisonous gas from volcanoes is harmful to health?

A. Hydrogen sulphide
B. Methane
C. Oxygen
D. Argon

Answer: A. Hydrogen sulphide

36. Which volcanic zone includes the Canary Islands?

A. Mid-world Mountain Belt
B. Pacific Ring of Fire
C. Andean Belt
D. East African Rift

Answer: A. Mid-world Mountain Belt

37. Which factor makes volcanic soil fertile?

A. Mineral-rich ash
B. Low rainfall
C. Sandy texture
D. Lack of vegetation

Answer: A. Mineral-rich ash

38. Which term describes movements causing instant changes on the earth’s surface?

A. Sudden movements
B. Diastrophic forces
C. Plate drift
D. Erosion

Answer: A. Sudden movements

39. What theory explains the movement of lithosphere plates?

A. Plate tectonics
B. Continental drift
C. Sea-floor spreading
D. Hot spot theory

Answer: A. Plate tectonics

40. Which process is responsible for the creation of magma chambers?

A. Melting of weak rocks
B. Cooling of lava
C. Erosion of crust
D. Sedimentation

Answer: A. Melting of weak rocks

41. Which region’s volcanic plains include over 400 sites and last erupted 7200 years ago?

A. Western Victorian Plains
B. Deccan Traps
C. Ethiopian Highlands
D. Columbia Plateau

Answer: A. Western Victorian Plains

42. Which Indian state has famous sulphur hot springs at Manikaran?

A. Himachal Pradesh
B. Uttarakhand
C. Kerala
D. Rajasthan

Answer: A. Himachal Pradesh

43. Which term describes violent eruptions that eject larger materials?

A. Bombs
B. Ash
C. Lapilli
D. Dust

Answer: A. Bombs

44. Which belt surrounds the Pacific with volcanoes?

A. Pacific Ring of Fire
B. Mid-Atlantic Ridge
C. Alpine Belt
D. Himalayan Belt

Answer: A. Pacific Ring of Fire

45. Magma finds escape routes through what in the earth’s crust?

A. Fissures
B. Uniform rock
C. Sedimentary layers
D. Sand layers

Answer: A. Fissures

46. From surface towards the centre of the earth, what increases?

A. Temperature and pressure
B. Gravity and light
C. Humidity and wind
D. Magnetism and tides

Answer: A. Temperature and pressure

47. Which process may create chambers for molten material under the crust?

A. Melting of weak rocks
B. Deposition of ash
C. Erosion by water
D. Weathering

Answer: A. Melting of weak rocks

48. Which classification describes volcanoes that are no longer likely to become active?

A. Extinct
B. Active
C. Dormant
D. Erupted

Answer: A. Extinct

49. Which African volcano is an example of an extinct volcano?

A. Mt Kenya
B. Mt Kilimanjaro
C. Mt Merapi
D. Mt Agung

Answer: A. Mt Kenya

50. Which volcano in Africa is dormant?

A. Mt Kilimanjaro
B. Mt Kenya
C. Mt Aconcagua
D. Mt Stromboli

Answer: A. Mt Kilimanjaro

51. The most recent eruption in the Western Victorian Plains occurred at:

A. Mount Napier
B. Mount Vesuvius
C. Mauna Loa
D. Mount Etna

Answer: A. Mount Napier

52. Approximately how many volcanic sites are there in the Western Victorian Plains?

A. Over 400
B. 100
C. 7,200
D. Six million

Answer: A. Over 400

53. About how many known active volcanoes may erupt at any time?

A. 20
B. 500
C. 100
D. 70

Answer: A. 20

54. How many active volcanoes are found in the Philippines within the Pacific Ring of Fire?

A. Over 100
B. 40
C. 70
D. 20

Answer: A. Over 100

55. How many active volcanoes are found in Indonesia along the Ring of Fire?

A. 70
B. 40
C. Over 100
D. 20

Answer: A. 70

56. How many active volcanoes are there in Japan?

A. 40
B. 70
C. Over 100
D. 20

Answer: A. 40

57. The only active volcano in India is located in:

A. Andaman and Nicobar Islands
B. Lakshadweep
C. Goa
D. Kerala

Answer: A. Andaman and Nicobar Islands

58. Which islands in the Atlantic are part of the Mid-world Mountain Belt?

A. Canary Islands
B. Hawaiian Islands
C. Philippine Islands
D. Andaman Islands

Answer: A. Canary Islands

59. Which volcanic mountain belt includes the Hawaiian Islands?

A. Mid-world Mountain Belt
B. Pacific Ring of Fire
C. Andes Belt
D. East African Rift

Answer: A. Mid-world Mountain Belt

60. What flows into the magma chamber, increasing its pressure?

A. Fresh magma
B. Ash
C. Water vapour
D. Gases

Answer: A. Fresh magma

61. Which feature results from cooling of volcanic ash around a vent?

A. Volcanic cone
B. Lava plateau
C. Caldera
D. Geyser

Answer: A. Volcanic cone

62. What is the term for molten rock fragments when still under the earth’s crust?

A. Magma
B. Lava
C. Pyroclast
D. Tephra

Answer: A. Magma

63. Which landforms on earth’s surface are called extrusive landforms?

A. Volcanic plateaus
B. Batholiths
C. Deltas
D. Canyons

Answer: A. Volcanic plateaus

64. What are landforms created on earth’s surface from volcanic activity called?

A. Extrusive landforms
B. Intrusive landforms
C. Fluvial landforms
D. Aeolian landforms

Answer: A. Extrusive landforms

Additional Assertion and Reason

1. Assertion (A): Endogenic forces are those arising from the interior of the earth.
Reason (R): Volcanic eruptions are sudden movements associated with internal forces of the earth.