Volcano Archives

1. The volcanic island ‘Barren Island’ is located in

The volcanic island ‘Barren Island’ is located in

[amp_mcq option1=”Chile” option2=”India” option3=”Italy” option4=”Iceland” correct=”option2″]

This question was previously asked in

UPSC CISF-AC-EXE – 2017

The correct answer is B.

Barren Island is an island located in the Andaman Sea.
It is a volcanic island and contains the only confirmed active volcano in India.
It is part of the Union Territory of Andaman and Nicobar Islands, India.

Barren Island is located about 138 km northeast of Port Blair, the capital of the Andaman and Nicobar Islands. The volcano erupted recently in 2017.

2. Consider the following: Pyroclastic debris Ash and dust Nitrogen c

Consider the following:

Pyroclastic debris
Ash and dust
Nitrogen compounds
Sulphur compounds

How many of the above are products of volcanic eruptions ?

[amp_mcq option1=”Only one” option2=”Only two” option3=”Only three” option4=”All four” correct=”option4″]

This question was previously asked in

UPSC IAS – 2024

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All four listed items are products of volcanic eruptions. Volcanic eruptions release a variety of materials into the atmosphere and onto the Earth’s surface.
1. Pyroclastic debris: This refers to fragmented solid material ejected during an eruption, ranging from fine ash and dust to larger bombs and blocks.
2. Ash and dust: These are fine particles of pulverized rock and glass ejected from the volcano. They can travel long distances and pose significant hazards.
3. Nitrogen compounds: Volcanic gases typically contain significant amounts of nitrogen (often as N2), along with smaller amounts of nitrogen compounds like ammonia (NH3). So, nitrogen compounds are among the gaseous products.
4. Sulphur compounds: Sulphur dioxide (SO2) and hydrogen sulphide (H2S) are common and often abundant volcanic gases. These compounds can have significant environmental impacts, including contributing to acid rain and atmospheric aerosols.
Therefore, all four are products of volcanic eruptions.

Volcanic products include solid ejecta (lava, pyroclastics) and gases. Common volcanic gases include water vapor, carbon dioxide, sulfur compounds, nitrogen compounds, hydrogen, carbon monoxide, and halogens.

The composition and quantity of volcanic products vary greatly depending on the type of volcano and the nature of the eruption. Volcanic ash plumes can disrupt air travel and affect climate.

3. What is the depression at the top of a volcano following a volcanic er

What is the depression at the top of a volcano following a volcanic eruption called?

[amp_mcq option1=”Chamber” option2=”Vent” option3=”Cinder” option4=”Crater” correct=”option4″]

This question was previously asked in

UPSC CAPF – 2021

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The depression at the top of a volcano following a volcanic eruption is called a crater. It is typically a bowl-shaped geological formation.

A volcanic crater is formed by explosive eruptions or collapse around a vent. It is the exit point for volcanic materials like lava, ash, and gases. Craters vary in size and shape.

A vent is the channel through which volcanic material rises to the surface. A magma chamber is a reservoir of molten rock beneath the surface. Cinder refers to porous, volcanic rock fragments (a type of pyroclastic material) ejected during eruptions. A caldera is a much larger depression, often miles wide, formed by the collapse of a volcano into its emptied magma chamber, usually after a very large eruption.

4. Consider the following statements about ‘Ring of Fire’: It is also k

Consider the following statements about ‘Ring of Fire’:

It is also known as circum-Pacific belt of volcanoes
It is an active seismic zone
It is a zone of divergent plate margin

Select the correct answer using the code given below :

[amp_mcq option1=”1 only” option2=”1 and 2 only” option3=”2 and 3 only” option4=”1, 2 and 3″ correct=”option2″]

This question was previously asked in

UPSC CAPF – 2017

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The correct answer is B) 1 and 2 only.

Statement 1 is correct: The ‘Ring of Fire’ is indeed known as the circum-Pacific belt, which is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.
Statement 2 is correct: It is an extremely active seismic zone due to the convergence and movement of tectonic plates, leading to frequent earthquakes.
Statement 3 is incorrect: The Ring of Fire is primarily characterized by *convergent* plate margins, specifically subduction zones, where one tectonic plate slides beneath another. While there are also areas of divergent and transform boundaries within or near the Pacific Basin, the dominant process driving the volcanism and seismicity of the Ring of Fire is subduction along convergent margins, not divergent boundaries (like mid-ocean ridges).

The Ring of Fire is a horseshoe-shaped zone that extends about 40,000 km (25,000 miles) and is associated with a continuous series of oceanic trenches, volcanic arcs, volcanic belts, and plate movements. It is home to about 75% of the world’s active volcanoes and 90% of the world’s earthquakes. Divergent plate margins, like the Mid-Atlantic Ridge, are areas where plates move apart, often leading to the formation of new crust and volcanism, but they are not the defining characteristic of the Ring of Fire.

5. Match List-I with List-II and select the correct answer using the code

Match List-I with List-II and select the correct answer using the code given below the Lists :
List-I (Volcano type)
A. Shield Volcano
B. Composite Volcano
C. Caldera
D. Flood Basalt Provinces
List-II (Location)
1. Indonesia
2. India
3. Hawaii
4. Philippines
Code :

	A	B	C	D
(a)	2	4	1	3
(b)	2	1	4	3
(c)	3	1	4	2
(d)	3	4	1	2

[amp_mcq option1=”(a)” option2=”(b)” option3=”(c)” option4=”(d)” correct=”option4″]

This question was previously asked in

UPSC CAPF – 2015

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Matching the volcano types with characteristic locations: A. Shield Volcanoes are known for effusive eruptions and broad structures, exemplified by those in Hawaii (3). B. Composite Volcanoes (Stratovolcanoes) are known for explosive eruptions and steep profiles, common in volcanic arcs like the Philippines (4, e.g., Pinatubo). C. Calderas are large collapse depressions, often associated with explosive eruptions, like Krakatoa in Indonesia (1). D. Flood Basalt Provinces are vast areas covered by massive basalt flows, with the Deccan Traps in India (2) being a prime example. Thus, the correct match is A-3, B-4, C-1, D-2.

Different types of volcanoes are associated with distinct geological settings and eruptive styles, leading to characteristic landforms often found in specific regions globally.

Shield volcanoes are typical of hot spots or divergent boundaries with basaltic magma. Composite volcanoes are characteristic of convergent plate boundaries with subduction zones. Calderas form from the collapse of a volcano after a large eruption. Flood basalts are associated with mantle plumes or rifting events.

6. Vapours of sulphur escaping from a volcano often form a crust on the r

Vapours of sulphur escaping from a volcano often form a crust on the rocks. The process involved is an example of

[amp_mcq option1=”condensation” option2=”precipitation” option3=”deposition” option4=”evaporation” correct=”option3″]

This question was previously asked in

UPSC NDA-2 – 2022

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The correct answer is deposition.

Deposition is the phase transition in which gas transforms into solid without passing through the liquid phase. Sulphur escaping from a volcano as vapour (gas) cools upon contact with rocks and directly forms a solid crust. This is the reverse of sublimation.

Condensation is the change of state from gas to liquid. Precipitation is the process of forming a solid from a solution or vapour phase, often used for meteorological phenomena (rain, snow, etc.) or chemical solid formation from a liquid. Evaporation is the change of state from liquid to gas.

7. Directions : The following 05 (Five) items consist of two statements,

Directions : The following 05 (Five) items consist of two statements, Statement I and Statement II. Examine these two statements carefully and select the answers to these items using the code given below :
Code :

Both the Statements are individually true and Statement II is the correct explanation of Statement I.
Both the Statements are individually true but Statement II is not the correct explanation of Statement I.
Statement I is true but Statement II is false.
Statement I is false but Statement II is true.

53.
Statement I: Volcanic eruption is accompanied by earthquakes.
Statement II: Volcanoes erupt water vapours and dust particles in the atmosphere.

[amp_mcq option1=”Both the Statements are individually true and Statement II is the correct explanation of Statement I.” option2=”Both the Statements are individually true but Statement II is not the correct explanation of Statement I.” option3=”Statement I is true but Statement II is false.” option4=”Statement I is false but Statement II is true.” correct=”option2″]

This question was previously asked in

UPSC NDA-1 – 2016

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The correct answer is B) Both the Statements are individually true but Statement II is not the correct explanation of Statement I.

Statement I is true. Volcanic eruptions are frequently preceded by or accompanied by earthquakes. These are often seismic events directly related to the movement of magma beneath the surface, the fracturing of rocks due to pressure buildup, or the rapid release of pressure during the eruption.
Statement II is also true. Volcanoes erupt various materials including gases (primarily water vapour), ash, dust particles, lava, and rock fragments.
However, Statement II (what volcanoes erupt) does not explain *why* volcanic eruptions are accompanied by earthquakes (Statement I). The earthquakes are caused by processes happening *before* or *during* the eruption related to magma dynamics and rock mechanics, not by the mere expulsion of water vapour and dust.

Volcanic earthquakes are distinct from tectonic earthquakes, although both involve ground shaking. Volcanic earthquakes are typically shallower and more localized around volcanic structures. They can be indicators of impending eruptions.

8. Which of the following statements regarding Arc Volcanoes is/are corre

Which of the following statements regarding Arc Volcanoes is/are correct ?

1. Arc volcanoes are found near divergent plate boundaries.
2. Some of the world’s classical examples of cone-shaped stratovolcanoes, such as Mount Fuji in Japan, Mayon in the Philippines are Arc volcanoes.
3. Some of the highest volcanoes on Earth are of the Arc type, notably Nevado Ojos del Salado in the Chilean Andes.

Select the answer using the code given below :

[amp_mcq option1=”2 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option2″]

This question was previously asked in

UPSC CDS-2 – 2024

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Statement 1 is incorrect. Arc volcanoes are typically found near convergent plate boundaries, where one tectonic plate subducts beneath another. This process leads to the melting of the mantle wedge above the subducting plate, generating magma that rises to the surface to form volcanoes in an arc shape parallel to the plate boundary. Divergent plate boundaries are associated with rift volcanism (like mid-ocean ridges) or flood basalts.

Statement 2 is correct. Volcanic arcs are known for producing explosive eruptions and building steep-sided, cone-shaped composite volcanoes (stratovolcanoes). Mount Fuji in Japan and Mount Mayon in the Philippines are indeed famous examples of stratovolcanoes located in the Pacific Ring of Fire, which is largely composed of volcanic arcs formed by subduction.

Statement 3 is correct. Volcanic arcs, particularly those associated with continental collision or significant crustal thickening, can host very high volcanoes. The Andes mountain range in South America is a classic example of a volcanic arc formed by the subduction of the Nazca Plate beneath the South American Plate. Nevado Ojos del Salado, located in the Chilean Andes, is one of the highest volcanoes in the world (and the highest active volcano).

– Arc volcanoes form at convergent plate boundaries (subduction zones).
– Stratovolcanoes like Fuji and Mayon are characteristic of volcanic arcs.
– High volcanoes, including Nevado Ojos del Salado, are found in some volcanic arcs like the Andes.

Volcanic arcs can be either continental (formed on the edge of a continent) or oceanic (forming a chain of volcanic islands). The shape of the arc is related to the curvature of the Earth and the angle of subduction.

9. Match List-I with List-II and select the correct answer using the code

Match List-I with List-II and select the correct answer using the code given below the Lists :

List-I (Active Volcano)	List-II (Location)
A. Mount Merapi	1. Hawaii
B. Sakurajima	2. Italy
C. Mount Vesuvius	3. Japan
D. Mauna Loa	4. Indonesia

[amp_mcq option1=”A-1, B-2, C-3, D-4″ option2=”A-1, B-3, C-2, D-4″ option3=”A-4, B-3, C-2, D-1″ option4=”A-4, B-3, C-1, D-2″ correct=”option3″]

This question was previously asked in

UPSC CDS-2 – 2020

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Matching the volcanoes with their locations:
– Mount Merapi is a very active volcano located in Indonesia.
– Sakurajima is an active composite volcano in Kagoshima Prefecture, Kyushu, Japan.
– Mount Vesuvius is a famous volcano located near Naples in Italy.
– Mauna Loa is one of the five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii. It is the world’s largest volcano by mass and area.
Thus, the correct matching is A-4, B-3, C-2, D-1.

– Mount Merapi: Indonesia
– Sakurajima: Japan
– Mount Vesuvius: Italy
– Mauna Loa: Hawaii (USA)

All listed volcanoes are known for their activity and geological significance. Understanding the location of major geographical features like volcanoes is important for world geography.

10. Which of the following statements about volcanoes are correct? 1. T

Which of the following statements about volcanoes are correct?

1. The strength of a volcano is measured by the Volcanic Explosive Index.
2. Iceland and Philippines were created by volcanic activity.
3. Volcanic soils are rich, deep and fertile and allow intensive agriculture to take place.

Select the correct answer using the code given below.

[amp_mcq option1=”1 and 2 only” option2=”2 and 3 only” option3=”1 and 3 only” option4=”1, 2 and 3″ correct=”option4″]

This question was previously asked in

UPSC CDS-1 – 2023

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Let’s evaluate each statement:
1. The strength of a volcano is measured by the Volcanic Explosive Index: The Volcanic Explosivity Index (VEI) is a scale used to measure the relative explosiveness of volcanic eruptions. It is based on factors like the volume of erupted material, height of the eruption column, and duration of the eruption. This statement is correct.
2. Iceland and Philippines were created by volcanic activity: Iceland is situated on the Mid-Atlantic Ridge, a divergent plate boundary where volcanic activity is frequent, leading to the formation and growth of the island. The Philippines is located in the Pacific Ring of Fire, an area characterized by intense seismic and volcanic activity due to plate tectonics, and its islands are largely volcanic in origin. This statement is correct.
3. Volcanic soils are rich, deep and fertile and allow intensive agriculture to take place: Soils derived from volcanic ash and lava (Andisols) are generally known for their high fertility due to the presence of minerals and nutrients. They are not always “deep,” as depth depends on the age of the soil and the accumulation of organic matter, but their fertility allows for very productive and intensive agriculture in many volcanic regions around the world (e.g., Indonesia, Japan, parts of Italy, Central America). The statement, while potentially slightly overgeneralizing depth, is fundamentally correct regarding the fertility and agricultural potential of volcanic soils. This statement is considered correct in this context.
Since all three statements are correct, the correct option is D.

– VEI measures volcanic eruption strength.
– Iceland and the Philippines are products of volcanic processes.
– Volcanic soils are typically fertile and support agriculture.

– Volcanic eruptions can also cause significant destruction through lava flows, ashfall, pyroclastic flows, and lahars.
– Despite the hazards, volcanic areas attract human settlement due to fertile soils, geothermal energy potential, and mineral deposits.