The sinkhole formed in Anantnag district of Jammu and Kashmir is a naturally occurring geological event and there is no cause for panic or worry, officials said here on Friday.
The sinkhole emerged on the Bringi nullah at Wandevalgam in Kokernag area of the south Kashmir district on February 11 at around 4 pm. It disrupted the entire flow of the stream.
The Anantnag district administration said while immediate mitigation measures were initiated, concurrent efforts to understand the scientific cause of the event and possible resolutions were also started.
While one intervention available was to immediately fill the sinkhole and divert the stream, however, given that sinkholes are naturally occurring geological events and pose no immediate danger, it was decided to investigate into the event scientifically and ensure that the intervention is scientifically rational and is not counterproductive, deputy commissioner, Anantnag, Piyush Singla said.
He said a similar event had occurred 27 years ago in the district and the same was the source of Achabal spring and it was necessary to ensure that the present sinkhole be investigated to prevent unintended drying of springs in any other part.
The deputy commissioner said four technical teams from the National Institute of Technology, Srinagar, Department of Earth Sciences, Kashmir University, Fisheries Department and Geology and Mining Department visited the spot and conducted technical tests, including using a Proton Precession Magnetometer (PPM) to understand the event.
As per the detailed study conducted by the teams, it has been learnt that a sinkhole is a naturally occurring geological event, a result of chemical weathering of rock formation. At the site of the sinkhole, the underlying rock formation in the area is soluble limestone (Triassic limestone). Dissolution over long periods creates cavities in the rocks and these may cave in gradually or suddenly, he said.
Singla said according to the PPM studies, the underlying cavern is about 100 metres long downstream.
Studies indicate that since water has been flowing into the sinkhole continuously since its emergence, there is possibility of large network of underground cavities or water holding reservoirs, he said.
The wide distribution of carbonate rocks in south Kashmir is well documented and the dissolution of these carbonate rocks can create various karstic features like swallow holes, sinkholes, conduits, shafts, caves and there’s no cause for panic or worry, he said.
The official said the events are naturally occurring geomorphic processes and several sinkholes due to collapse of roof of underground Karst caves have been reported previously and have been published in newspapers.
A mapping of karst cavernous/cave network systems in Anantnag must be carried out to create a vulnerability profile of the district which will serve as a guiding framework for physical infrastructure development, he said.
Further, geophysical and gravity surveys have been recommended for profiling to establish the path of underground water flow and length of the cavity, he added.
The administration has decided to carry out tracer studies, he said.
In the meantime, he said, appropriate measures to fill the sinkhole and creation of another diversion is being done shortly in consultation with technical and engineering experts.