Volcanism, the eruption of molten rock (magma) onto the Earth's surface, is a significant geological process shaping the planet’s landscape. While India is not situated on a major plate boundary known for frequent volcanic activity like the ‘Ring of Fire’, it exhibits evidence of both past and present volcanism. The most prominent manifestation of this is the Deccan Traps, a large igneous province formed by massive volcanic eruptions around 66 million years ago. Understanding the volcanism in India is crucial for comprehending the region’s geological evolution, resource potential, and associated hazards. Geological History of Volcanism in India The volcanic history of India can be broadly divided into several phases: 1. Deccan Traps (Late Cretaceous – Early Paleogene) The most significant volcanic event in India’s history is the formation of the Deccan Traps. These extensive basaltic lava flows cover a large portion of western and central India, spanning over 500,000 square kilometers. The eruptions are believed to have occurred over a relatively short period, possibly linked to the Reunion hotspot and the breakup of the Gondwana landmass. The massive release of volcanic gases is hypothesized to have contributed to the Cretaceous-Paleogene extinction event. 2. Andaman & Nicobar Islands (Present) The Andaman and Nicobar Islands are part of the Indo-Burmese volcanic arc, formed due to the subduction of the Indo-Australian Plate under the Eurasian Plate. Barren Island and Narcondam Island are the only confirmed active volcanoes in India. Barren Island: Experienced eruptions in 2004, 2005, 2006-07, and most recently in 2023. It’s a stratovolcano characterized by steep slopes and a crater. Narcondam Island: A smaller stratovolcano, also showing signs of recent activity, though less frequent than Barren Island. 3. Other Volcanic Regions Besides the Deccan Traps and the Andaman & Nicobar Islands, evidence of volcanism is found in other parts of India, though generally less pronounced: Rajmahal Hills (Jharkhand): Basaltic lava flows associated with the Rajmahal Traps, formed during the Late Jurassic-Early Cretaceous period. Gujarat: Minor volcanic occurrences in the form of basaltic dykes and sills. Lakshadweep Islands: Some islands show evidence of volcanic origin, though they are primarily coral atolls. Types of Volcanism in India India exhibits different types of volcanism: Region Type of Volcanism Characteristics Deccan Traps Flood Basalt Volcanism Highly fluid lava flows covering vast areas; fissure eruptions. Andaman & Nicobar Islands Stratovolcanic Eruptions Steep-sided cones; explosive eruptions; viscous lava; pyroclastic flows. Rajmahal Hills Basaltic Lava Flows Similar to Deccan Traps, but on a smaller scale. The volcanism in India is primarily basaltic in nature, although some andesitic and rhyolitic rocks are also found, particularly in the Andaman & Nicobar Islands. In conclusion, volcanism in India, though not as frequent or intense as in some other parts of the world, has played a crucial role in shaping the country’s geological landscape and influencing its environmental history. The Deccan Traps represent a massive volcanic event with global implications, while the active volcanoes in the Andaman & Nicobar Islands pose localized hazards. Continued monitoring and research are essential to understand the potential risks and benefits associated with volcanism in India.

Volcanism in India: Types & Distribution | UPSC Mains GEOLOGY-PAPER-I 2012

Volcanism in India

How to Approach

This question requires a concise yet comprehensive overview of volcanism in India. The approach should be to first define volcanism and then detail the geological history of volcanic activity in the Indian subcontinent, focusing on regions like the Deccan Traps, Andaman & Nicobar Islands, and other minor occurrences. Mention the types of volcanism observed and their associated geological features. Structure the answer chronologically and geographically for clarity. Avoid excessive detail on global volcanism; focus solely on the Indian context.

Geological History of Volcanism in India

The volcanic history of India can be broadly divided into several phases:

1. Deccan Traps (Late Cretaceous – Early Paleogene)

The most significant volcanic event in India’s history is the formation of the Deccan Traps. These extensive basaltic lava flows cover a large portion of western and central India, spanning over 500,000 square kilometers. The eruptions are believed to have occurred over a relatively short period, possibly linked to the Reunion hotspot and the breakup of the Gondwana landmass. The massive release of volcanic gases is hypothesized to have contributed to the Cretaceous-Paleogene extinction event.

2. Andaman & Nicobar Islands (Present)

The Andaman and Nicobar Islands are part of the Indo-Burmese volcanic arc, formed due to the subduction of the Indo-Australian Plate under the Eurasian Plate. Barren Island and Narcondam Island are the only confirmed active volcanoes in India.

Barren Island: Experienced eruptions in 2004, 2005, 2006-07, and most recently in 2023. It’s a stratovolcano characterized by steep slopes and a crater.
Narcondam Island: A smaller stratovolcano, also showing signs of recent activity, though less frequent than Barren Island.

3. Other Volcanic Regions

Besides the Deccan Traps and the Andaman & Nicobar Islands, evidence of volcanism is found in other parts of India, though generally less pronounced:

Rajmahal Hills (Jharkhand): Basaltic lava flows associated with the Rajmahal Traps, formed during the Late Jurassic-Early Cretaceous period.
Gujarat: Minor volcanic occurrences in the form of basaltic dykes and sills.
Lakshadweep Islands: Some islands show evidence of volcanic origin, though they are primarily coral atolls.

Types of Volcanism in India

India exhibits different types of volcanism:

Region	Type of Volcanism	Characteristics
Deccan Traps	Flood Basalt Volcanism	Highly fluid lava flows covering vast areas; fissure eruptions.
Andaman & Nicobar Islands	Stratovolcanic Eruptions	Steep-sided cones; explosive eruptions; viscous lava; pyroclastic flows.
Rajmahal Hills	Basaltic Lava Flows	Similar to Deccan Traps, but on a smaller scale.

The volcanism in India is primarily basaltic in nature, although some andesitic and rhyolitic rocks are also found, particularly in the Andaman & Nicobar Islands.

Additional Resources

Key Definitions

Hotspot Volcanism

Volcanism caused by plumes of hot mantle material rising from deep within the Earth, independent of plate boundaries. The Hawaiian Islands are a classic example.

Stratovolcano

A conical volcano built up by many layers (strata) of hardened lava, tephra, pumice, and volcanic ash. They are characterized by steep slopes and explosive eruptions.

Key Statistics

The Deccan Traps cover an area of approximately 500,000 square kilometers.

Source: Geological Survey of India (as of 2023 knowledge cutoff)

The Rajmahal Traps are estimated to have formed around 118 million years ago.

Source: ResearchGate (as of 2023 knowledge cutoff)

Examples

2023 Barren Island Eruption

The eruption of Barren Island in May 2023, observed by the National Centre for Seismology, demonstrated the continued volcanic activity in the region and prompted increased monitoring efforts.

Frequently Asked Questions

▶Is India prone to major volcanic eruptions?

While India has experienced large volcanic events in the past (Deccan Traps), the current risk of a major eruption is relatively low. The active volcanoes are small and located in remote islands, limiting the potential impact on densely populated areas.