Model Answer

Land Subsidence

Land subsidence refers to the gradual sinking or sudden collapse of the earth’s surface due to the removal or displacement of subsurface materials. It can occur naturally due to earthquakes, erosion, or sinkholes, or as a result of human activities like groundwater extraction, mining, and infrastructure development.

Factors Contributing to Subsidence in Joshimath, Uttarakhand

In Joshimath, land subsidence is attributed to both natural and anthropogenic factors:

• Built on Ancient Landslide Material: Joshimath is situated on loose sand and stone deposits from an ancient landslide, which lack high load-bearing capacity, making the region vulnerable to subsidence under increasing infrastructure and population pressure.
• Geographic Faults: The region is located along a tectonic fault line where the Indian Plate subducts under the Eurasian Plate, contributing to instability.
• Extreme Weather: Frequent heavy rainfall causes erosion and exacerbates landslides, as seen during the 2013 and 2021 floods.
• Hydroelectric Projects: Construction activities, including tunneling for hydropower projects, have disrupted aquifers, contributing to land subsidence.
• Unplanned Construction: Lack of proper drainage systems and unregulated construction has further aggravated the problem (Source: Indian Institute of Remote Sensing, M.C. Mishra Committee).