Which one among the following is a dormant volcano?

1. Nature of Volcanism: Magma and Lava (basic)

To understand volcanism, we must first look deep beneath our feet. The Earth is not a cold, static rock; it is a dynamic engine powered by endogenic forces. This internal energy comes primarily from the decay of radioactive elements, primordial heat left over from the planet's formation, and tidal friction FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Geomorphic Processes, p.38. As we go deeper, the temperature rises at an average rate of 1°C for every 32 metres. This geothermal gradient, combined with a reduction in pressure at plate boundaries, causes rocks to melt into a molten state known as Magma Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Natural Hazards and Disaster Management, p.10.

The distinction between Magma and Lava is simply one of location: Magma is the molten rock stored within the Earth's crust, while Lava is that same material once it breaches the surface through a volcanic vent Physical Geography by PMF IAS, Volcanism, p.139. The nature of an eruption depends heavily on the chemical composition of this lava, specifically its silica content. Basaltic lava is rich in iron and magnesium but low in silica; this makes it very fluid (low viscosity), allowing it to flow rapidly and quietly for long distances, often reaching temperatures of 1,000°C Physical Geography by PMF IAS, Volcanism, p.140. In contrast, acidic or rhyolitic lavas are high in silica, highly viscous (sticky), and tend to cause violent, explosive eruptions.

Geographers classify volcanoes into three categories based on their activity levels:

• Active: Eruptions occur frequently. Examples include Mount Etna and Mount Stromboli in Italy. Stromboli is so consistently active it is nicknamed the 'Lighthouse of the Mediterranean' Physical Geography by PMF IAS, Volcanism, p.142.
• Dormant: These are "sleeping" volcanoes that haven't erupted in a long time but show signs they could wake up. Mount Kilimanjaro is a classic example; while its cones like Kibo haven't erupted recently, they are geologically young enough to be considered dormant rather than extinct Physical Geography by PMF IAS, Volcanism, p.142.
• Extinct: Volcanoes that have shown no activity for thousands of years and are highly unlikely to erupt again.

Feature	Basaltic Lava (Basic)	Rhyolitic Lava (Acidic)
Silica Content	Low	High
Viscosity	Low (Fluid/Runny)	High (Thick/Sticky)
Eruption Style	Quiet, non-explosive	Violent, explosive

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Geomorphic Processes, p.38; Physical Geography by PMF IAS, Volcanism, p.139-142; Environment and Ecology, Majid Hussain (Access publishing 3rd ed.), Natural Hazards and Disaster Management, p.10

2. Volcanic Landforms: Shield to Stratovolcanoes (intermediate)

To understand why volcanoes take different shapes, we must look at the viscosity of their lava. Think of viscosity as "thickness"—honey has high viscosity, while water has low viscosity. In volcanology, this is determined by silica content. When lava is basaltic (low silica), it flows like water over great distances, creating a broad, low-profile mountain resembling a warrior’s shield. These Shield Volcanoes are the largest of all volcanoes on Earth FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Interior of the Earth, p.23. The Hawaiian islands, specifically Mauna Loa, are the gold standard here. They are generally non-explosive unless water enters the vent, creating steam-driven blasts Physical Geography by PMF IAS, Chapter 11: Volcanism, p.141.

On the other end of the spectrum, we have Composite Volcanoes (or Stratovolcanoes). These are the iconic, steep, snow-capped peaks like Mt. Fuji or the Philippines' Mt. Mayon. They are built from andesitic lava, which is cooler and more viscous than basalt. Because this lava is "sticky," it doesn't travel far; instead, it piles up near the vent. These volcanoes are built of alternating layers (strata) of hardened lava, ash, and volcanic fragments (pyroclastics) Physical Geography by PMF IAS, Chapter 11: Volcanism, p.141. Due to the high pressure of trapped gases in thick lava, these eruptions are often violently explosive.

Beyond shape, geographers classify volcanoes by their eruptive history. Active volcanoes, like Italy's Mt. Etna or Stromboli (the 'Lighthouse of the Mediterranean'), erupt frequently. Dormant volcanoes are those that have been quiet for a long time but retain the potential to wake up. A classic example is Mt. Kilimanjaro in Tanzania, which consists of three volcanic cones: Kibo, Mawenzi, and Shira Physical Geography by PMF IAS, Chapter 11: Volcanism, p.142. Finally, if a volcano's summit collapses inward after a massive eruption, it forms a Caldera—a large depression that often fills with water to become a beautiful caldera lake, such as Lake Toba in Sumatra Certificate Physical and Human Geography, GC Leong, Lakes, p.83.

Feature	Shield Volcano	Stratovolcano (Composite)
Lava Type	Basaltic (Low Viscosity)	Andesitic/Rhyolitic (High Viscosity)
Shape	Gentle slopes, very broad	Steep, symmetrical cone
Eruption Style	Effusive (Quiet flows)	Explosive (Ash & Pyroclastics)

Sources: FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Interior of the Earth, p.23; Physical Geography by PMF IAS, Chapter 11: Volcanism, p.141-142; Certificate Physical and Human Geography, GC Leong, Lakes, p.83

3. Global Distribution: The Plate Tectonic Connection (intermediate)

To understand where volcanoes appear, we must look at the Earth's crust as a giant jigsaw puzzle of tectonic plates. Volcanic activity is not random; it is highly concentrated along plate margins, where these giant slabs of rock meet, pull apart, or grind against each other Environment and Ecology, Majid Hussain, Natural Hazards and Disaster Management, p.12. There are three primary 'scenes' where the volcanic drama unfolds:

• Convergent Boundaries (The Ring of Fire): This is the world's most intense volcanic zone. As one plate dives beneath another (subduction), it melts into magma and rises to the surface. The Pacific Ring of Fire is the classic example, containing over 70% of the world's active volcanoes, including the perfectly symmetrical Mt. Mayon in the Philippines Certificate Physical and Human Geography, GC Leong, Volcanism and Earthquakes, p.35.
• Divergent Boundaries (Mid-Ocean Ridges): Here, plates move apart, allowing basaltic lava (low in silica and very fluid) to well up from the mantle. This creates the massive 70,000 km system of mid-oceanic ridges and the Great Rift Valley of East Africa, where you'll find the famous Mt. Kilimanjaro Physical Geography by PMF IAS, Divergent Boundary, p.130/153.
• Hotspots: These are isolated 'leaks' in the middle of a plate (intra-plate) where a plume of heat rises from deep within the asthenosphere to create volcanic chains like Hawaii Environment and Ecology, Majid Hussain, Natural Hazards and Disaster Management, p.12.

Beyond their location, we classify volcanoes by their 'temperament' or activity level. Active volcanoes like Mt. Etna and Mt. Stromboli (the 'Lighthouse of the Mediterranean') erupt frequently. Dormant volcanoes, such as Mt. Kilimanjaro with its three cones (Kibo, Mawenzi, and Shira), have not erupted in historic times but are geologically 'young' enough to potentially wake up. Finally, extinct volcanoes are those unlikely to ever erupt again as their magma source has dried up or moved away Physical Geography by PMF IAS, Volcanism, p.141-142.

Feature	Convergent (Subduction)	Divergent (Rift/Ridge)
Distribution	Pacific Ring of Fire, Andes	Mid-Atlantic Ridge, East African Rift
Magma Type	Often Viscous (Explosive)	Fluid Basaltic (Fissure eruptions)
Example	Mt. Mayon (Philippines)	Mt. Kilimanjaro (Tanzania)

Sources: Environment and Ecology by Majid Hussain, Natural Hazards and Disaster Management, p.12; Certificate Physical and Human Geography by GC Leong, Volcanism and Earthquakes, p.35; Physical Geography by PMF IAS, Volcanism, p.130, 141-142, 153, 155

4. The East African Rift System (intermediate)

To understand the **East African Rift System (EARS)**, we must look at it as a giant 'crack' in the Earth's crust where a continent is literally pulling itself apart. While most **divergent boundaries** (where plates move away from each other) occur on the ocean floor as mid-oceanic ridges, the EARS is a rare and spectacular example of a **continental rift**. This system stretches over 4,800 km, starting from the Afar Triple Junction in the north—where the Red Sea, Gulf of Aden, and the main rift meet—and extending south toward Mozambique Certificate Physical and Human Geography, GC Leong, The Earth's Crust, p.22. As the Nubian and Somalian plates diverge, the crust thins, leading to the formation of a deep valley flanked by high plateaus and mountains.
The system is divided into two primary branches with distinct personalities. The **Eastern Rift (Gregory Rift)** is famous for its massive volcanic activity and high peaks, while the **Western Rift (Albertine Rift)** is defined by its dramatic, deep-water lakes. Before the rifting even began, the region experienced massive **flood basalt eruptions** and significant uplift, creating the Ethiopian and East African plateaus Physical Geography by PMF IAS, Divergent Boundary, p.129. Geologically, this is a 'spreading site' where the continental crust is gradually being replaced by basaltic oceanic crust—a process that will eventually turn the rift into a new ocean basin FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI, Distribution of Oceans and Continents, p.33.
Because the crust is being stretched and broken, the EARS is a powerhouse of **seismology and volcanism**. It is the largest seismically active rift on Earth today, with the most intense earthquake activity centered around the **Afar Depression** Physical Geography by PMF IAS, Divergent Boundary, p.130. The volcanism here ranges from highly active to dormant and extinct:

Volcano Status	Example in EARS	Key Characteristics
Dormant	Mount Kilimanjaro	Has three cones (Kibo, Mawenzi, Shira); has not erupted recently but could in the future.
Extinct	Mount Kenya	A stratovolcano that has ceased all activity and is being eroded.
Active	Erta Ale / Ol Doinyo Lengai	Frequent or continuous eruptions; located within the rift valley floor.

The EARS teaches us that Earth's surface is never static. What begins as a series of faults and valleys eventually leads to the birth of a sea, and later, a "mighty ocean," as seen in the transition of the Red Sea just to the north Physical Geography by PMF IAS, Divergent Boundary, p.129.

Sources: Certificate Physical and Human Geography, GC Leong, The Earth's Crust, p.22; Physical Geography by PMF IAS, Divergent Boundary, p.129-130; FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.), Distribution of Oceans and Continents, p.33

5. Classification by Eruption Frequency (exam-level)

When we classify volcanoes based on their eruption frequency, we are essentially looking at their past behavior to predict their future potential. Geologists typically categorize them into three distinct stages: Active, Dormant, and Extinct. It is important to remember that these are not permanent labels; a volcano is a dynamic system that can transition between these phases over geological time Certificate Physical and Human Geography, Volcanism and Earthquakes, p.29.

Active Volcanoes are those that erupt frequently or have shown significant activity within recorded history. For instance, Mount Stromboli in Italy is so consistently active that it is famously nicknamed the 'Lighthouse of the Mediterranean'. Other notable examples include Mount Etna (Italy) and the perfectly symmetrical Mount Mayon in the Philippines Physical Geography by PMF IAS, Volcanism, p.141.

Dormant Volcanoes, often called 'sleeping' volcanoes, are those that have not erupted for a long time but still possess the potential to become active. They undergo long intervals of repose. A classic example is Mount Kilimanjaro in Tanzania, which consists of three volcanic cones (Kibo, Mawenzi, and Shira) Physical Geography by PMF IAS, Volcanism, p.142. The danger with dormant volcanoes is that they can wake up unexpectedly; for example, Mount Vesuvius remained quiet for over 1,500 years before a catastrophic eruption in 1631 A.D. Environment and Ecology by Majid Hussain, Natural Hazards and Disaster Management, p.11.

Extinct Volcanoes are those that have shown no signs of activity for thousands of years and are unlikely to erupt again because their magma supply has been cut off. Mount Kenya is a well-known extinct stratovolcano. As a volcano approaches extinction, it often enters a waning stage where it only emits gases and steam; these vents are known as fumaroles or solfataras Physical Geography by PMF IAS, Volcanism, p.142. Over time, the craters of extinct volcanoes may fill with water, forming crater lakes.

Category	Status	Key Example
Active	Frequent eruptions or recent activity.	Mt. Stromboli, Mt. Etna
Dormant	'Sleeping'; capable of erupting after long repose.	Mt. Kilimanjaro, Mt. Vesuvius
Extinct	No activity in historic times; supply cut off.	Mt. Kenya

Sources: Certificate Physical and Human Geography, GC Leong, Volcanism and Earthquakes, p.29; Physical Geography by PMF IAS, Volcanism, p.141-142; Environment and Ecology, Majid Hussain, Natural Hazards and Disaster Management, p.11

6. Mapping Major World Volcanoes (exam-level)

To master the mapping of world volcanoes, we must first understand that they aren't scattered randomly. They follow the lines of Plate Tectonics. Most active volcanoes are found at convergent boundaries (subduction zones) or divergent boundaries (rifts). Geographers generally classify them by their activity levels: Active (erupting or signs of activity), Dormant (hasn't erupted in a long time but could), and Extinct (unlikely to erupt again).

The Mediterranean region is a classic study area, formed by the complex interaction of the African and Eurasian plates Physical Geography by PMF IAS, Volcanism, p.156. Here, we find Mount Stromboli, famously nicknamed the 'Lighthouse of the Mediterranean' because it has been erupting continuously for centuries with fountain-like bursts of magma Physical Geography by PMF IAS, Volcanism, p.145. Nearby, Mount Vesuvius stands as a reminder of nature's power; its massive Plinian eruption in AD 79 buried the city of Pompeii under layers of ash and stone Physical Geography by PMF IAS, Volcanism, p.146.

Moving to the Indo-Pacific, we encounter some of the world's most symmetrical and dangerous peaks. Mount Mayon in the Philippines is a stratovolcano celebrated for its "perfect cone" shape. In Indonesia, Mount Tambora holds the record for one of the most powerful eruptions in history (1815). The sheer volume of ash it injected into the atmosphere blocked sunlight, leading to 1816 being known as the 'Year Without a Summer', causing global crop failures and famine Physical Geography by PMF IAS, Volcanism, p.147.

Finally, we look at Mount Kilimanjaro in Tanzania. Unlike the continuous activity of Stromboli, Kilimanjaro is classified as dormant. It is composed of three distinct volcanic cones: Kibo, Mawenzi, and Shira. While it hasn't erupted in recent history, its relatively young summit craters suggest it still has the potential to become active, separating it from truly extinct volcanoes.

Volcano	Location	Key Characteristic
Stromboli	Italy (Lipari Islands)	Continuous eruptions; "Lighthouse of the Mediterranean".
Vesuvius	Italy (Bay of Naples)	Famous for AD 79 Plinian eruption (Pompeii).
Tambora	Indonesia	1815 eruption caused global cooling (Year Without a Summer).
Kilimanjaro	Tanzania	Dormant stratovolcano with three volcanic cones.

Sources: Physical Geography by PMF IAS, Volcanism, p.145; Physical Geography by PMF IAS, Volcanism, p.146; Physical Geography by PMF IAS, Volcanism, p.147; Physical Geography by PMF IAS, Volcanism, p.156

7. Solving the Original PYQ (exam-level)

Now that you have mastered the classification of volcanic landforms based on their eruption frequency, this question serves as a perfect application of those principles. In your study, we categorized volcanoes into active, dormant, and extinct. The UPSC often tests your ability to distinguish between these categories by using iconic global examples. The key here is to identify a peak that hasn't erupted in modern history but still shows signs of internal geological activity, fitting the "sleeping" profile rather than the "dead" profile of an extinct volcano.

Walking through the options, Mount Kilimanjaro stands out as the correct answer. Located in Tanzania, it is a massive stratovolcano with three distinct cones: Kibo, Mawenzi, and Shira. While Kibo still emits gases (fumaroles), there have been no recorded eruptions in recent history, making it a textbook example of a dormant volcano as detailed in Physical Geography by PMF IAS. In contrast, Mount Stromboli and Mount Etna in Italy are frequently in the news for their constant activity; in fact, Stromboli is famously dubbed the 'Lighthouse of the Mediterranean' due to its persistent eruptions. Similarly, Mount Mayon in the Philippines is one of the most active peaks in the Pacific Ring of Fire, known for its dangerous and frequent activity.

The trap in this question lies in the "grey area" between dormant and extinct. Some sources might lean toward calling Kilimanjaro extinct, but geographers classify it as dormant because its summit craters are geologically young and it sits atop a thinning crust in the East African Rift Valley. When tackling UPSC geography, always associate active volcanoes with famous "Ring of Fire" or "Mediterranean" peaks (like Mayon, Etna, or Stromboli), and look for Kilimanjaro or Japan's Mount Fuji as the primary representatives of the dormant category. Distinguishing between these based on their potential for future activity is the secret to never missing these marks.