Not just Joshimath! Nainital and two other Uttarakhand towns are at risk of sinking, warns geologist

Joshimath sinking: Not just Joshimath, three other famous towns in Uttarakhand - Nainital, Uttarkashi, and Champawat - are also at risk of sinking. A geologist has warned that what the country is seeing in Joshimath, can very easily and soon replicate in the districts of Nainital, Uttarkashi, and Champawat.

Dr Bahadur Singh Kotlia, Professor of Geology at Kumaun University, has said that these three towns are highly prone to seismic activity, reactivation of faultlines, and being hit by a massive surge of population and construction activities. "The foundation of these cities is very poor, making them very vulnerable," Kotlia said while speaking to India Today.

The risk for towns like Nainital has increased due to heavy tourism and major construction. Half of the area of Nanital township is covered with debris generated by landslides, according to a report published in 2016. In a study released late last year, Dr Kotlia identified the vulnerability of Nainital by analysing the 2009 Balia Nala Landslide.

The study concluded that the slope pattern seemed to be the fundamental factor for the catastrophe as most of the area possessed very high slopes. "Secondly, rock types also play a very dominant role in the mass movements followed by the tectonic set-up of the area," it said.

In 2016, a geological study around Nainital found that the town comprises limestone with shale and slate which are highly crushed and weathered due to the presence of the Nainital Lake Fault. These rocks and the overlying soil have very low strength, the study, conducted by researchers from Wadia Institute of Geology and Graphic Era Hill University, said.

Hundreds of houses and roads have developed cracks in Joshimath, a temple town in the Chamoli district of Uttarakhand. People have been evacuated and the district administration has started marking red cross marks on buildings facing potential danger due to land subsidence. So far, Singhdhar, Gandhinagar, Manoharbaag, and Sunil wards have been declared unsafe.

However, experts believe that several other towns in the foothills of the Himalayas are vulnerable to land subsidence. Land subsidence occurs when large amounts of groundwater have been withdrawn from certain types of rocks, according to the US Geological Survey.

In Joshimath, the land underneath is moving because of a weak foundation and enhanced toe erosion due to incessant rainfall and floods.

According to Professor Kotlia, the reactivation of the Main Central Thrust (MCT2) - a geological fault where the Indian Plate has pushed under the Eurasian Plate along the Himalayas - is the prime reason behind the sudden subsidence in Joshimath. This MCT-2 zone, the professor said, has reactivated and is causing the sinking of ground in Joshimath. He, however, said that no geologist can predict when this reactivation will happen.

Dr Shresth Tayal, Senior Fellow at the Centre for Himalayan Ecology of TERI, said the Himalayan Belt's natural topography in areas such as Joshimath is sedimentary in nature, making it softer and weaker than other rocks. "The natural terrain, continuous deforestation on a large scale, rapid and unplanned urbanisation, and heavy construction activities are exacerbating the crisis," he said.