Joshimath Sinking: Uttarakhand Town Declared ¡®Landslide-Subsidence Zone¡¯, What Does It Mean?

Joshimath, a small town in Uttarakhand, is on edge as 610 of its 4,500 structures are showing signs of collapsing. Over 60 residents who were living in uninhabitable homes in the sinking town of Joshimath were moved to temporary relief centres after authorities declared it a landslide-subsidence zone.

At least 90 more families reportedly need to be evacuated. Four to five locations in the Himalayan town have been designated as relief centres by the local government.

What is happening?

In a high-level conference with representatives from the state governments, the National Disaster Management Authority (NDMA), the Geological Survey of India (GSI), and the National Institute of Hydrology (NIH), the decision was taken to designate the area as a landslide and subsidence-hit zone.

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The Indian Express reported that recently, as many as 68 households had been evacuated to relief centres, despite the fact that many people refused to leave their homes and blamed the construction for the breaches.

What is land subsidence?

Subsidence, as defined by the National Oceanic and Atmospheric Administration (NOAA), is the term that refers to surface sinking as a result of subterranean material movement. It can occur for a variety of man-made or natural reasons, such as the exploitation of water, oil, or natural resources, along with mining activities. Subsidence has many well-known causes, including earthquakes, soil degradation, and soil compaction.

The website of US-based website also notes that this phenomenon "happens over very large areas like whole states or provinces, or very small areas like the corner of your yard."

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Why is this happening?

Joshimath is one of 395 villages that have been recognised as being in Uttarakhand's disaster-prone belt, which covers more than 12 districts.

Although the specific cause of the Joshimath land subsidence is still unknown, scientists speculate that uncontrolled construction, excessive population, restriction of the natural flow of water, and hydropower activities may be to blame. Additionally, earthquakes are more likely to occur at this place, since the region is in a seismic zone.

According to The Indian Express, the possibility that such an incident will occur in the area was originally highlighted some 50 years ago when the MC Mishra committee report was published and it issued a warning against "unplanned development in this area and outlined the natural vulnerabilities."

A survey was conducted in 2021, at the request of a Supreme Court-appointed panel which concluded that the city was built on landslide material.

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This indicates that it rests on a deposit of sand and stone, not rock, which has a low load-bearing capacity. And due to this, the region is very sensitive to the ever-growing infrastructure and population.

Moreover, it's possible that a poor drainage system also contributed to the area's sinking. According to experts, unauthorised development has blocked the natural flow of water, which ultimately causes regular landslides.

Geologists further suspect that the development of the all-weather Char Dham road and the National Thermal Power Corporation's (NTPC) Tapovan-Vishnugad 520 MW hydropower project may be the primary causes of this rapid ground subsidence.