Context: The exact reason behind Joshimath land subsidence is still unknown but experts cite unplanned construction, over-population, obstruction of the natural flow of water, and hydel power activities as possible causes.
About Land Subsidence:
- According to the National Oceanic and Atmospheric Administration (NOAA), subsidence is the sinking of the ground because of underground material movement.
- Reasons can be manmade or natural:
- removal of water, oil, or natural resources, along with mining activities
- Soil erosion and
- Soil compaction
Reasons behind Joshimath subsidence:
- unplanned construction,
- obstruction of the natural flow of water and hydel power activities.
- the area is a seismic zone, which makes it prone to frequent earthquakes.
- the subsidence in Joshimath might have been triggered by the reactivation of a geographic fault —
- defined as a fracture or zone of fractures between two blocks of rock — where the Indian Plate has pushed under the Eurasian Plate along the Himalayas.
Source: Indian Express