| PYQ Relevance:
[UPSC 2020] Discuss the geophysical characteristics of Circum-Pacific Zone. Linakge: This question is about a region known for earthquakes and volcanoes. The article mainly talks about quakes caused by human activity but also mentions that these usually happen in places already on fault lines or where tectonic plates are shifting—areas like the Circum-Pacific. So, it’s important to understand these natural zones when looking at how human actions might trigger earthquakes. |
Mentor’s Comment: Human-induced earthquakes are increasingly drawing scientific and public attention, as research shows that human activities like groundwater extraction, dam construction, and fracking can trigger or accelerate seismic activity, particularly in tectonically sensitive regions such as Delhi-NCR, the Western Ghats, and parts of Maharashtra and Kerala.
Today’s editorial analyses the Issues related to Human-induced earthquakes in India. This topic is important for GS Paper I (Geography), GS Paper II (Governance) and GS Paper III (Disaster Management) in the UPSC mains exam.
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Let’s learn!
Why in the News?
Recent studies in India have highlighted a correlation between excessive groundwater depletion and increased seismic events, especially in Delhi.
What are human-induced earthquakes?
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How do activities like groundwater extraction and dams trigger quakes in India?
- Groundwater Depletion Weakens Crustal Stability: Excessive extraction of groundwater reduces pore pressure, leading to a shift in stress within the earth’s crust. Eg: In Delhi-NCR, increased seismic activity between 2003–2012 has been linked to excessive groundwater loss.
- Reservoir-Induced Seismicity (RIS): The weight of large reservoirs exerts additional pressure on underlying faults, triggering quakes. Eg: The 1967 Koynanagar earthquake (magnitude 6.3) was linked to the Koyna Dam in Maharashtra.
- Water Infiltration into Fault Zones: Water from reservoirs or excessive irrigation can seep deep into fault lines, lubricating them, and making them more likely to slip. Eg: Seismic tremors near Mullaperiyar Dam in Kerala are suspected to be induced due to water infiltration in a seismically sensitive region.
- Load Variation Due to Filling and Emptying of Dams: Rapid filling or draining of reservoirs changes the stress distribution, causing small or moderate tremors. Eg: In the Himalayan region, such stress changes are a concern for dams like Tehri Dam.
- Ground Subsidence from Overuse of Aquifers: Excessive groundwater extraction leads to land subsidence, altering the natural equilibrium of stress in the crust. Eg: Regions in North Gujarat have experienced subsidence, making them more vulnerable to fault reactivation and quakes.
Why is Delhi-NCR prone to quakes from groundwater loss?
- Rapid Groundwater Depletion Alters Stress Fields: Excessive groundwater extraction reduces the hydrostatic pressure underground, disturbing the natural stress balance in fault zones. This stress redistribution can reactivate dormant faults, triggering seismic activity. Eg: Studies from 2003–2012 show increased microseismic activity in parts of Gurgaon and Faridabad, correlated with falling water tables.
- Aquifer-Related Land Subsidence: Continuous overuse of aquifers causes the land to sink (subsidence), which can strain the Earth’s crust and disturb nearby fault lines. In Delhi-NCR, land sinking has been recorded in Dwarka, Kapashera, and parts of Noida, increasing quake risk. Eg: A 2021 study by IIT-Kanpur showed that excessive aquifer use led to ground subsidence and elevated seismic hazard.
- Built-Up Pressure on Seismically Active Faults: Delhi-NCR sits near the Mahendragarh-Dehradun fault and Delhi-Haridwar ridge, making it naturally earthquake-prone. When groundwater is extracted, it weakens the structural resistance of rocks, making nearby active faults more vulnerable. Eg: Minor tremors in Rohini and West Delhi (2020-21) were suspected to be linked to combined stress from tectonics and human activity.
How does climate change contribute to seismic risks?
- Melting Glaciers Increase Uplift Pressure: Rapid glacial melt in the Himalayas (due to rising temperatures) reduces surface weight. This triggers isostatic rebound — the crust rises and shifts, which can activate faults beneath. Eg: In Uttarkashi (Uttarakhand), increased seismic activity has been observed near retreating Gangotri Glacier, linked to glacial thinning and uplift.
- Changing Rainfall Patterns Cause Landslides and Crustal Stress: Intense rainfall and flash floods (exacerbated by climate change) cause rapid groundwater recharge and erosion, disturbing fault stability. Eg: In Kodagu (Karnataka), unusually heavy rains in 2018 triggered landslides and minor tremors due to destabilized slopes and crustal shifts.
- Sea-Level Rise and Coastal Seismic Pressure: Rising sea levels increase water load on coastal plates, especially in delta regions. This can suppress or activate tectonic stresses near coastlines. Eg: In Sundarbans (West Bengal), changes in sediment load and sea-level rise have raised concerns of future seismic risks in this low-lying, tectonically sensitive zone.
What are the steps taken by the Indian Government?
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Way forward:
- Integrated Land and Water Management: Promote sustainable groundwater use, recharge practices, and land-use planning to reduce land subsidence and seismic vulnerability.
- Expand Monitoring and Preparedness: Enhance seismic monitoring networks and public awareness programs to improve early warning systems and disaster resilience.
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