LAND SUBSIDENCE

Current Context : In Chamoli’s Nanda Nagar (Uttarakhand), people are witnessing land subsidence, adding to the state’s natural calamities like landslides, flash floods, and cloudbursts.

About Land Subsidence

• Meaning: Gradual settling or sudden sinking of the Earth’s surface.
• Causes:
  • Natural: Earthquakes, volcanic activity, collapse of cavities, compaction of soil.
  • Human-induced: Excess groundwater withdrawal, mining, and energy extraction.

Impacts

• Damage to infrastructure (roads, buildings, pipelines).
• Increases flood risk and reduces aquifer storage capacity.
• Causes saltwater intrusion and changes in river/stream flow.
• High maintenance costs for public infrastructure.

Global Context

• Estimated 12 million sq. km of land worldwide is vulnerable.
• Reported in USA, China, Iran, Indonesia, Vietnam, Mexico, Egypt, Japan, Italy, and now India.