4 July 2022
Tupul: a landslide disaster in Manipur, India
On 30 June 2022 a very large landslide occurred at Tupul in Noney district of Manipur in Northern India. As of 3 July 2022 the confirmed toll was 42 people, with a further 20 people reported to be missing. A total of 18 people have been rescued. The majority of the fatalities consisted soldiers who were accommodated on the site of the landslide, with reports that they were from the 107 Battalion of the Territorial Army. The prospect of any further survivors is extremely low.
The best image that I have seen of the landslide was tweeted by Karma Paljor:
— Karma Paljor (@Karma_Paljor) July 1, 2022
There is also good drone footage on the following Youtube video (which has some annoying music):-
The drone footage confirms that the valley is not blocked by the landslide, which was an earlier concern. Indeed, it shows operations underway to widen the spillway.
The location of the landslide is 24.804, 93.674. The Google Earth image below shows the site on 24 March 2021:-
The image shows extensive slope works being undertaken at Tupul – this is for the construction of the Jiribam to Imphal railway line, which is planned to be completed by December 2023. Some of the works shown in the image appear to demonstrate questionable construction approaches, including large amounts of sediment being released into the river system.
The section of slope that has failed is shown below:-
There are a number of aspects of this site, prior to the failure, that give me cause for concern, including the very steep upper part of the slope, the lobate form of the lower slopes and the large bend in the river. I would like to see the engineering geomorphological and geological interpretation of this site that was surely (?) undertaken prior to construction.
The section that has collapsed had been cut, so inevitably this must be the leading potential cause of the landslide. The width of the landslide appears to correspond closely to the section of cut slope, which may be an indication of process and causation. I have tried to annotate the image from Karma Paljor to indicate the main features – of course this is highly speculative:-
My initial (speculative) interpretation is that the cut slope failed, creating the large debris mass seen in the foreground of the image. The location of the destroyed buildings gives a sense of the movement direction and distance. The area that I have shaded appears to be a secondary failure from higher up the slope, probably because of a loss of support. This is a deep seated collapse that may have implications for the stability of the other parts of the slope. This scar has then been partially infilled by smaller failures around the steep backscarp. These are likely to continue for some time.
Note the water flowing down the rear scarp. The main part of the SW summer monsoon will occur over the coming weeks. A key concern right now must be the stability of the other cut slopes at this site.
Finally, it goes without saying that this landslide should be investigated independently and in a transparent manner, with the outcomes published and lessons learnt.