What Is Land Subsidence?
Land Subsidence is a process of downward vertical movement of the earth’s surface. This process can be caused by both natural and human activities. Land Subsidence totally differs from slope movement in that it requires little or no horizontal movement.
In other words Land Subsidence is a process of ground sinking and it is mainly caused by underground material movements both naturally or human activities. Directly or indirectly Sustainable Development is the reason for the Land Subsidence.
Mainly Land Subsidence process arised by the dissolution of underlying carbonate rock by the groundwater, withdrawal of fluid lava from the beneath of solidified crust of rock, mining of natural resources, pumping of groundwater and petroleum.
This time Land Subsidence is a global concern to geologists, geotechnical engineers, surveyors, Land owners, builders and the general public also. Pumping of petroleum has led to Land Subsidence of as much as 30ft in many locations around the world.
National Oceanic and Atmospheric Administration Report About Land Subsidence
According to the National Oceanic and Atmospheric Administration (NOAA) Land Subsidence is the “Sinking of the land surface because of underground material movement”. It can happen for both man made or natural. It may be caused by the removal of excess groundwater, oil, natural resources along with mining activities.
Land Subsidence In India
Land Subsidence in India is a biggest concern particularly in Joshimath, Uttarakhand, India. Not only in India but also around the world Land Subsidence is the biggest challenge. India’s sinking cities are Mumbai, Delhi, Chennai and Kolkata. All cities are Metro cities and the main reason for land sinking in these cities is over groundwater pumping.
Causes Of Land Subsidence
Land Subsidence causes when large amounts of groundwater have been pumping from certain types of rocks as like fine-grained sediments both naturally or man made.
And the other causes of Land Subsidence are mining, pumping Subsidence fluids like groundwater or petroleum, natural gas etc. Earthquakes, soil erosion, seasonal or climatic effects and soil compaction are also some of the most well known causes of the Subsidence.