Human-Induced Earthquakes
Recent studies show the increasing frequency of earthquakes caused by human activities. These quakes, known as human-induced earthquakes, arise from actions that alter the stress and strain on the Earth’s crust. India, among other countries, is witnessing such seismic events linked to groundwater extraction, dam construction, and energy production methods. Understanding these processes is vital for managing risks in quake-prone regions.
Definition and Causes of Human-Induced Earthquakes
Human-induced earthquakes result from human activities that disturb the Earth’s crust. These include mining, groundwater extraction, dam impoundment, fluid injection into the ground, and large-scale construction. Such activities load or unload the crust repeatedly, causing strain to build between tectonic plates. This strain can trigger seismic activity in vulnerable zones.
Groundwater Extraction and Seismicity in India
Excessive groundwater pumping reduces underground water pressure, destabilising the crust. Research in the National Capital Region shows a rise in shallow earthquakes between 2003 and 2012, coinciding with drop in the water table. Seismic activity declined after water levels stabilised post-2014. The Gangetic plains, where groundwater depletion is severe due to irrigation needs, face similar risks.
Dam Reservoirs and Earthquake Risks
Large dams alter the load on the Earth’s surface, sometimes triggering earthquakes. The 1967 Koynanagar quake in Maharashtra, which killed over 180 people, is linked to water loading from the Koyna dam. Similar seismic activity has been recorded near the Mullaperiyar dam in Kerala. Regulations on dam filling and emptying, as seen in the US, are recommended to manage such risks in India.
Energy Extraction and Seismic Activity
Energy production methods like hydraulic fracturing (fracking) involve injecting fluids underground, which can induce earthquakes. India has 56 fracking sites across six states. Regions like Palghar in Maharashtra have reported quakes possibly linked to fluid migration. Enhanced seismic monitoring is needed to track such isolated plate deformations.
Climate Change and Seismic Modulation
Climate change indirectly influences seismic activity by altering surface water loads. Melting glaciers reduce pressure on tectonic plates, triggering quakes in polar regions. Changing rainfall patterns cause sudden water loading or drought conditions, affecting stress on faults. The Western Ghats experience tremors linked to heavy rainfall, while droughts have reactivated faults elsewhere, such as in California.
Risk Management and Scientific Monitoring
Earthquake risks from human activities are only in fault zones or areas of plate deformation. Managing groundwater extraction and dam operations scientifically can reduce risks. Establishing dense seismic networks in vulnerable regions is crucial for early detection and understanding. Experts caution against attributing all seismic events solely to human causes, as these activities may only accelerate or delay natural tectonic processes.
| Related | |
|---|---|
