Joshimath crisis: Why is Uttarakhand town 'sinking' and what's land subsidence?

Pic Credit: File Photo

Cracks on roads, homes, walls and now a collapsed temple - all these events have created an atmosphere of panic across Joshimath, a town located in Uttarakhand. Reports say the town is 'sinking' or experiencing land subsidence, a phenomenon in which the ground level sinks or sinks lower over time. There are several factors contributing to Joshimath's subsidence, including its location in an area prone to landslides, extreme weather events, and geological factors. 

Uttarakhand Chief Minister Pushkar Singh Dhami, on Saturday (January 7), visited the homes of the affected families in Joshimath and promised to ensure their safety and rehabilitation. Dhami stated that it was undecided whether the residents will be migrated from the town but said they needed to be evacuated immediately.

जिसके लिए हम पूरी प्रतिबद्धता के साथ कार्य कर रहे हैं।

समस्या के समाधान हेतु तात्कालिक तथा दीर्घकालिक कार्य योजना पर गंभीरता से कार्य किया जा रहा है। खतरे की जद में आए पूरे शहर में सुरक्षात्मक कार्य कराए जाएंगे। जिसके लिए विस्तृत प्लान तैयार किया जा रहा है। pic.twitter.com/YMRF7ypbv9 — Pushkar Singh Dhami (@pushkardhami) January 7, 2023

What is land subsidence?

Land subsidence is when the ground sinks or settles. It can happen because people are taking too much water or minerals from the ground, which causes the ground to sink.

It can also be caused by natural processes, like soil compaction or the movement of the earth's crust.

Land subsidence can cause problems like damage to buildings and roads, and can make it more likely for flooding to occur.

Why is Joshimath sinking - Main reasons

Geological factors are playing a significant role in Joshimath's subsidence, as per a study by Uttarakhand State Disaster Management Authority (USDMA) from August 2022. The town is situated on the Vaikrita Thurst (VT), a tectonic fault line, and is also very close to two other main geological fault lines: the Main Central Thrust (MCT) and the Pandukeshwar Thrust (PT). The study further stated that this makes the town highly vulnerable to sinking due to tectonic activity.

Extreme weather events such as heavy rainfall and floods have also contributed to Joshimath's subsidence. The flood events of June 2013 and February 2021 caused toe erosion and slope instability in the area, increasing the risk of subsidence.

Unplanned construction in the area has also contributed to Joshimath's subsidence. Hydroelectric schemes have been constructed around Joshimath and Tapovan, including the Vishnugad HE Project. This construction, along with the use of heavy machinery by the Border Roads Organisation (BRO) to build the Helang bypass, has the potential to induce further landslides and contribute to the town's subsidence. All construction around Joshimath has now been banned.

To address the issue of land subsidence in Joshimath, it will be important for authorities to consider the long-term stability of the town and implement measures to mitigate the risks of subsidence. This may include better planning and regulation of construction projects in the area, as well as efforts to mitigate the effects of extreme weather events.