Great Nicobar Infrastructure Project Earthquake Risks

The ₹72,000-crore Great Nicobar Infrastructure Project (GNIP) is set to transform the region with a port, airport, township, and power plant. Despite its scale, concerns have risen over the seismic and tsunami risks in this highly active zone. The Environmental Impact Assessment (EIA) report downplays the chance of a mega earthquake like the 2004 disaster. However, many scientists argue that detailed site-specific studies are lacking and the region’s geological complexity demands caution.

Seismic Risk Assessment in GNIP

The EIA report, prepared by Vimta Labs, bases its risk evaluation on a 2019 Indian Institute of Technology-Kanpur (IIT-K) study. It estimates the return period for mega earthquakes (magnitude 9 or above) at 420–750 years. For large earthquakes (above 7.5 magnitude), the return period is 80–120 years. The report suggests a low probability of a mega earthquake occurring soon. However, it overlooks some critical geological uncertainties and does not include all findings from the IIT-K study.

Scientific Concerns and Gaps

IIT-K’s research revealed at least seven large tsunami events in 8,000 years near the Andaman segment. It also noted a 2,000-year gap in sediment data, creating uncertainty in future earthquake predictions. Experts like Professor Javed Malik stress the need for site-specific studies in Nicobar to understand local fault behaviour and tsunami inundation patterns. The 2004 earthquake’s epicentre was in Indonesia’s Banda Aceh, but a quake originating in Nicobar could have different impacts.

Complex Fault Lines and Geo-Dynamics

Geoscientist C.P. Rajendran marks multiple unknown rupture lines south of the Andamans towards Nicobar. These may hold pent-up seismic energy. Earthquake recurrence is non-linear, meaning long quiet periods can be followed by sudden major quakes. Local fault lines and land level changes in Great Nicobar Island add to the region’s geo-dynamic nature. This complexity raises questions about the safety of large infrastructure projects there.

Government and Environmental Responses

The Ministry of Earth Sciences admits forecasting exact earthquake timing is impossible and that the project involves calculated risk. Design codes will be adapted for seismic safety but uncertainties remain. The GNIP has received preliminary environmental and forest clearances. Still, the National Green Tribunal ordered a review due to concerns over biodiversity loss, deforestation, and impacts on indigenous tribes. The area falls under the highest seismic zone category five and is vulnerable due to the Indian plate subducting beneath the Burmese Microplate along the Andaman Trench.

Historical Context of Seismic Activity

The 2004 Indian Ocean tsunami was triggered by a 9.2 magnitude earthquake near Banda Aceh. It devastated the Andaman and Nicobar Islands, killing over 1,500 people locally and 10,000 Indians overall. The event brought into light the region’s vulnerability to massive subduction zone earthquakes and tsunamis. This history puts stress on the need for rigorous scientific assessments before undertaking major development.

Questions for UPSC:

1. Critically analyse the challenges in earthquake prediction and risk management in seismically active zones with examples from the Indian subcontinent.
2. Explain the concept of subduction zones and discuss their role in generating tsunamis, citing the Andaman and Nicobar region.
3. What are the environmental and social implications of large infrastructure projects in ecologically sensitive areas? Illustrate with reference to island ecosystems.
4. With suitable examples, comment on the role of scientific studies in shaping disaster-resilient infrastructure policies and the limitations faced in implementation.

Answer Hints:

1. Critically analyse the challenges in earthquake prediction and risk management in seismically active zones with examples from the Indian subcontinent.

1. Earthquake prediction lacks precise timing and location forecasting due to complex fault dynamics and non-linear recurrence intervals.
2. Seismic zones like the Andaman and Nicobar Islands have multiple unknown rupture lines with pent-up energy, complicating risk assessment.
3. Return periods (e.g., 420–750 years for mega quakes in Andaman) provide probabilistic estimates but cannot guarantee exact prediction.
4. Insufficient site-specific studies hinder accurate hazard mapping and infrastructure planning in vulnerable areas.
5. Risk management involves calculated risk acceptance, with design codes adapted but uncertainty remains high.
6. Examples – 2004 Indian Ocean earthquake-tsunami brought into light gaps in preparedness and prediction in the Andaman-Nicobar region.

2. Explain the concept of subduction zones and discuss their role in generating tsunamis, citing the Andaman and Nicobar region.

1. Subduction zones occur where one tectonic plate dives beneath another, causing strain accumulation and seismic activity.
2. The Indian plate subducts beneath the Burmese Microplate along the Andaman Trench, a major seismic hotspot.
3. Sudden release of strain during megathrust earthquakes displaces large volumes of water, triggering tsunamis.
4. The 2004 tsunami was caused by a 9.2 magnitude earthquake in this subduction zone near Banda Aceh, devastating Andaman and Nicobar Islands.
5. Subduction zones have long return periods but can produce catastrophic earthquakes and tsunamis when they rupture.
6. Geological evidence (sediments) shows repeated past tsunami events in the region, confirming ongoing subduction activity.

3. What are the environmental and social implications of large infrastructure projects in ecologically sensitive areas? Illustrate with reference to island ecosystems.

1. Large projects can cause biodiversity loss, habitat destruction, and deforestation, threatening endemic species and fragile ecosystems.
2. Displacement and disruption of indigenous communities occur due to land acquisition and altered livelihoods.
3. Island ecosystems are especially vulnerable due to limited land area and unique ecological balance.
4. Environmental clearances may overlook long-term impacts without thorough site-specific studies.
5. Examples – Great Nicobar Infrastructure Project risks tree-felling, biodiversity loss, and impact on resident tribes.
6. National Green Tribunal’s order for environmental review marks governance challenges in balancing development and conservation.

4. With suitable examples, comment on the role of scientific studies in shaping disaster-resilient infrastructure policies and the limitations faced in implementation.

1. Scientific studies provide data on seismic hazards, fault lines, recurrence intervals, and tsunami inundation patterns essential for risk-informed planning.
2. Site-specific studies enable tailored design codes, safer building practices, and informed location choices for infrastructure.
3. Example – IIT-Kanpur’s sediment analysis revealed tsunami history but was not fully incorporated in GNIP’s EIA report.
4. Limitations include incomplete data, lack of site-specific assessments, political-economic pressures, and uncertainty in predictions.
5. Implementation gaps arise from balancing development urgency with scientific caution, often leading to calculated risks.
6. Effective disaster resilience requires integrating scientific inputs with policy, governance, and community engagement, which remains challenging.