A report released by the National Remote Sensing Centre (NRSC) of the Indian Space Research Organisation (ISRO) on its website revealed that the revered Joshimath town sank -5.4 cm in a period of just 12 days. The central part of Joshimath town, army helipad and Narsingh Mandir — the winter seat of Lord Badrinath — have been witnessing rapid subsidence, the images released on the NRSC website showed. The report was later removed from the website on Friday.
Dhan Singh Rawat, Uttarakhand Cabinet Minister, told The Hindu that he spoke to the Director, NRSC-ISRO, and asked if the report that was stating that Joshimath sank -5.4 cm in the past 12 days was their official take, and the director told him that they would update the report.
“I told them that how can they release such a report at this time. It is creating panic. They told me that they will update the report. Now, I am being told that it has been removed,” Mr. Rawat said.
When The Hindu contacted Prakash Chauhan, Director, NRSC-ISRO to seek an explanation on why the report was later removed from the website, he didn’t respond to repeated calls, texts and emails.
Another senior scientist working with the NRSC-ISRO told The Hindu that the report was removed because it was being misinterpreted.
“It was done on a thorough scientific study but was being misinterpreted negatively,” he said.
Rapid subsidence event
The report, whose copy is with The Hindu, stated that between December 27, 2022, and January 8, 2023, a rapid subsidence event was triggered in the town. The region subsided around -5.4 cm within a span of 12 days and the areal extent of subsidence had also increased.
The observations in the report maintained that slow subsidence up to ~ -9 cm within the Joshimath town is recorded over a period of seven months between April and November 2022.
Between December 27, 2022 and January 8, 2023 a rapid subsidence event was triggered.
A subsidence zone resembling a generic landslide shape was identified (tapered top and fanning out at base). Crown of the subsidence is located near Joshimath-Auli road at a height of 2180 m.
The report was compiled by Sentinel-1 SAR imagery (Descending pass) which was processed using the ‘DInSAR’ technique to identify the possible location and extent of land subsidence in long and short time intervals, the ISRO maintained.
(With Inputs from Geetanath V)