Human-induced earthquakes have become an increasing concern globally. Recent studies show how human activities influence seismic events by altering stress in the Earth’s crust. This knowledge is vital for managing risks in vulnerable regions.
Definition and Global Overview
Human-induced earthquakes occur due to human actions rather than natural tectonic movements. Since the late 19th century, over 700 such quakes have been documented worldwide. Activities like mining, groundwater extraction, dam construction, fluid injection, and large-scale engineering projects can trigger seismic activity by repeatedly loading and unloading the Earth’s crust.
Groundwater Extraction and Seismicity in India
In India, excessive groundwater pumping has been linked to shallow earthquakes, especially in the National Capital Region (NCR). Between 2003 and 2012, falling water tables coincided with increased seismic events. After 2014, when groundwater levels stabilised, seismic activity reduced. This is because removing underground water reduces pressure on geological faults, causing jolts on the surface. Though most quakes in Delhi-NCR are minor, the region’s location on fault lines places it in seismic risk Zone 4, making monitoring essential.
Dams and Reservoir-Induced Earthquakes
Large dams can cause earthquakes by changing the water load on the crust. The 1967 Koynanagar earthquake in Maharashtra, which killed over 180 people, was linked to the nearby Koyna dam. Similar seismic activity has been observed near the Mullaperiyar dam in Kerala. Countries like the USA regulate dam filling rates to reduce risks. Experts recommend similar regulations in India, especially in seismically active zones like the Himalayas, where large dams may worsen stress on faults.
Energy Extraction and Seismic Risks
India’s growing energy needs increase seismic risks. Hydraulic fracturing (fracking) involves injecting fluids underground to release oil or gas but may induce earthquakes. India has 56 fracking sites across six states. In Maharashtra’s Palghar district, repeated tremors since 2018 may be linked to fluid movements underground. Enhanced seismic monitoring is needed in such areas to better understand and manage risks.
Climate Change and Earthquake Frequency
Climate change indirectly affects seismic activity. Melting glaciers reduce pressure on Earth’s crust, triggering earthquakes in polar regions. Changing rainfall patterns alter surface water loads, which can modulate tectonic stress. For example, heavy rains in the Western Ghats cause tremors by affecting mountain stability. Droughts also influence seismicity by changing groundwater extraction and reactivating faults, as seen in California in 2014.
Scientific Challenges and Risk Management
It remains difficult to quantify how much human activities contribute to tectonic stress accumulation. Not all groundwater depletion or dam construction causes quakes; only regions on fault lines or with active plate deformation are vulnerable. Experts caution against blaming human activities alone for earthquakes. Instead, these factors may accelerate or delay natural tectonic processes. Scientific monitoring and sustainable resource management are crucial to mitigate risks.
Questions for UPSC:
- Taking example of reservoir-induced seismicity, discuss the role of large dams in altering local geological stability and its implications for disaster management in India.
- Examine the impact of groundwater extraction on seismic activity with reference to the National Capital Region and discuss sustainable groundwater management strategies.
- Analyse how climate change can indirectly influence earthquake frequency and intensity. How should this understanding shape environmental and disaster policies?
- Critically discuss the challenges in distinguishing human-induced earthquakes from natural tectonic events and the importance of seismic monitoring networks in India.
