Discovering the Geological Marvel: India's Sole Active Mud Volcano

Mud volcanoes represent a fascinating geological phenomenon distinct from their fiery counterparts. These structures emit cool mixtures of mud, water, and gases—primarily methane (CH₄) and carbon dioxide (CO₂)—from deep subsurface layers, driven by pressure from decaying organic matter or tectonic forces. Unlike traditional volcanoes that spew molten lava at extreme temperatures, mud volcanoes operate at near-ambient surface conditions, often bubbling gently or erupting explosively under seismic influence. Globally, approximately 2,500 such features have been documented, with Azerbaijan hosting over 350, earning it the title of the 'motherland of mud volcanoes.' In India, they number between 10 and 12, predominantly clustered in the tectonically active Andaman and Nicobar Islands.

The Baratang Island mud volcano, India's only consistently active one, exemplifies this rarity. Situated in Jarwa Creek, about 150 kilometers from Port Blair, it sits within a subduction zone where the Indian Plate dives beneath the Burmese Plate, fostering frequent earthquakes and gas upwelling. This dynamic setting not only shapes the volcano's behavior but also positions it as a natural laboratory for probing Earth's deep processes.

BSIP's Pioneering Initiative: A New Chapter in Palaeoclimate Research

The Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous research body under India's Ministry of Earth Sciences headquartered in Lucknow, has embarked on an ambitious study of the Baratang mud volcano and nearby dormant sites at Diglipur. Founded in 1946 by Professor Birbal Sahni—a pioneering Indian palaeobotanist—BSIP specializes in reconstructing Earth's ancient environments through plant fossils, pollen grains, microfossils, and multiproxy analyses. Its mandate encompasses palaeoclimate dynamics, vegetation shifts, and hydroclimatic variability, particularly tied to the Indian Summer Monsoon (ISM).

Led by Senior Scientist Dr. Shilpa Pandey from the Quaternary Division, the project seeks to decode millennia-spanning climate shifts embedded in the volcano's sediments. Dr. Pandey, with expertise in quaternary palaeoclimates, sea-level changes, and mangrove archives, recently led a field expedition that cataloged active mud flows, persistent methane seepage, and stratified sediment layers. These observations highlight the site's potential as a continuous record of environmental flux. BSIP Director Prof. Mahesh G. Thakkar emphasized expanding efforts with advanced sedimentology, geochemistry, isotopes, and palaeoenvironmental proxies to bridge deep Earth tectonics with surface climate systems.

Unveiling the Field Survey: Fresh Insights from Baratang and Diglipur

Dr. Pandey's team meticulously surveyed the Baratang site, noting layered deposits that encapsulate historical eruptions, seismic tremors, and ecological transitions. Methane bubbles piercing the mud surface signal ongoing hydrocarbon migration, while the sediments—comprising clay, silt, and microfossils—offer pristine proxies untouched by surface weathering. At Diglipur, dormant volcanoes provided comparative data on quiescence versus activity, revealing subtle gas emissions even in repose.

This hands-on exploration underscores the challenges of fieldwork in remote, seismically volatile terrains. Access via boat through mangrove channels demands precision, as tidal fluctuations and sudden gas bursts pose risks. Yet, these hurdles yield invaluable samples: mud cores for pollen extraction, foraminifera for salinity insights, ostracods for temperature cues, and gas pockets for isotopic signatures.

Recent Eruption: A Tectonic Wake-Up Call from October 2025

Reviving after over two decades of dormancy, the Baratang mud volcano erupted dramatically on October 2, 2025, around 1:30 PM. Eyewitnesses reported a thunderous blast propelling mud skyward, forming a 3-4 meter mound and blanketing over 1,000 square meters. The Geological Survey of India (GSI) dispatched a seven-member team on October 7, confirming four vent clusters spanning 500 square meters—up from prior 100 square meters—with central heights of 2 meters. Mud temperatures hovered at 29-30°C, pH weakly alkaline (8.0-8.3), and an oily sheen hinted at hydrocarbons.

Foraminiferal analysis dated ejected lithoclasts (sandstone/shale from Mithakari Group) to the Oligocene epoch, circa 23 million years ago—a period of global cooling and grassland expansion. Possible triggers include diapiric shale uplift, rapid subsidence, or fault-guided fluid expulsion, amplified by Andaman's subduction dynamics. Last major activity predates 2005; the 2004 Sumatra-Andaman megaquake (M9.2) had previously induced eruptions.

GSI urged safety measures: restricted access, viewpoints, fencing, and signage, given unpredictable violence.

Decoding Proxies: From Mud to Millennia-Old Climate Narratives

At BSIP's labs, samples undergo multiproxy dissection. Pollen grains reveal past vegetation—tropical forests versus grasslands—mirroring monsoon strength. Microfossils like foraminifera and ostracods track salinity, temperature, and sea-level oscillations. Stable isotopes (δ¹⁸O, δ¹³C) in carbonates pinpoint precipitation regimes, while organic geochemistry flags methane origins: biogenic (microbial) or thermogenic (deep thermal).

Step-by-step: Cores are sliced chronologically; pollen slides prepared via acid digestion; microfossils sieved and identified under microscopy; gases chromatographed for composition. Radiocarbon or OSL dating anchors timelines. This integrates to model ISM variability, seismic-climate feedbacks, and natural GHG pulses.

Methane's Dual Role: Hazard and Climate Messenger

Methane, 25-80 times more potent than CO₂ over 20 years, dominates mud volcano emissions. Globally, these sites vent 6-9 million tons annually, a notable fossil CH₄ fraction potentially amplifying warming. At Baratang, seepage quantifies natural baselines amid anthropogenic rises. Reconstructions may show emission spikes during deglaciations or seismic swarms, informing models like IPCC AR7 on geological forcings.

This study on southern Hydrate Ridge mud volcanoes links compression to CH₄/CO₂ fluxes, paralleling Andaman tectonics.

Geoheritage and Conservation: Safeguarding Natural Archives

Dr. Pandey advocates designating these as geoheritage sites for science, education, and culture. Tourism booms post-eruption risk degradation; regulated viewing preserves integrity. BSIP's work bolsters India's National Geoheritage protocol, akin to global UNESCO sites like Azerbaijan's Golestan Mud Volcanoes.

Stakeholders—MoES, ANI administration, locals—gain from hazard mapping, eco-tourism, and research hubs, fostering community stewardship.

Tectonic-Climate Interplay in the Andaman Arc

Andaman's geology—Ophiolites, accretionary prisms—amplifies mud volcanism. Post-2004 quake surges link seismicity to eruptions, with mud breccias archiving strain histories. BSIP integrates palaeo-data with seismic catalogs, probing if monsoons lubricate faults via pore pressure or if quakes trigger ISM perturbations via dust aerosols.

Implications for India's Climate Resilience

India faces intensifying cyclones, monsoons, and GHG feedbacks. Baratang records analogize past hyperthermals (e.g., PETM), forecasting methane hydrate destabilization offshore Andamans. Policymakers leverage for NAPCC updates, while energy sector scouts hydrocarbons.

Real-world: Similar Taiwanese mud volcanoes forecast quakes; Azerbaijan models emissions. BSIP's outputs inform IMD, NDMA.

Future Horizons: Collaborations and Technological Frontiers

Prof. Thakkar envisions drone gas mapping, AI-proxy modeling, international tie-ups (e.g., Azerbaijani institutes). Student training via RMES-2026 workshops builds capacity. Preliminary results eyed for AGU/EGU 2027.

This study exemplifies interdisciplinary palaeosciences driving actionable climate intelligence.

Legacy of Andaman Research: Building on BSIP Traditions

BSIP's Andaman legacy—Eocene pollen from Baratang muds—evolves into holistic palaeo-volcanology. Recent mangrove talks by Dr. Pandey (Jan 2026) complement, linking coastal buffers to volcanic GHG.

• Past: 1996 palynology of Baratang vents.
• Present: Multiproxy Holocene ISM from Majuli.
• Future: Tectono-climatic models.

Stakeholder views: GSI collaboration enhances; locals value hazard insights; global peers applaud novelty.

Photo by Artem Beliaikin on Unsplash