New Scientific Study Highlights Seismic Risk Across the Andaman–Nicobar Region
A new study by researchers from the Department of Geology and Geophysics, IIT Kharagpur, presents an updated probabilistic seismic hazard assessment of the Andaman–Nicobar and Sumatra regions using 37,660 earthquake events recorded between 1881 and 2025.
In simple terms, Great Nicobar lies within a highly active tectonic system where the Indo-Australian Plate converges obliquely beneath the Burma-Sunda Plate. This movement is accommodated through the Sunda megathrust, major fault systems and deformation within the Earth's crust.
The study maps major active structures including the Sunda Subduction Front, West Andaman Fault, Central Andaman Rift, North Andaman Rift and other fault systems, several of which have produced significant historical earthquakes.
The findings show elevated seismic hazard along the Andaman–Nicobar arc, with hazard increasing towards the southern segment and the Nicobar region. The study estimates bedrock peak ground acceleration of approximately 0.25–0.40 g for a 10% probability of exceedance in 50 years, increasing to 0.40–0.70 g for a 2% probability of exceedance in 50 years along the Sunda megathrust and Nicobar segment.
The researchers conclude that earlier seismic assessments may have underestimated hazard in parts of this tectonically complex region, and emphasise the need for site- and region-specific seismic assessment for infrastructure planning and risk mitigation in the Andaman–Nicobar Islands.
For context, the study notes that the 26 December 2004 Mw 9.0–9.3 Sumatra–Andaman earthquake ruptured more than 1,000 km of the Sunda megathrust and generated the catastrophic Indian Ocean tsunami.
Scientific reference:
Saini, S., Shahabuddin, M. & Singha Roy, P.N.S. Updated Comprehensive Probabilistic Seismic Hazard Analysis of the Andaman-Nicobar and Sumatra Regions. Scientific Reports (2026). DOI: 10.1038/s41598-026-64505-9.
Note: The study does not assess the Great Nicobar Project itself. Its significance for the project is that it provides updated regional evidence on the tectonic setting and seismic hazard that must be considered when planning major infrastructure in the Nicobar region.
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