According to environmental monitoring firm Geomatic Ventures, who analysed the data, the sinking was caused by the drilling of a vertical tunnel as part of works extending the Northern Line to Battersea in November 2017. The firm looked at over 2000 satellite images using specialist technology, allowing them to detect any land movement on a millimetre scale.
Paul Bhatia, CEO of Geomatic Ventures, believes there is no need for residents to worry as the sinking is spread out evenly over a large area, so there’s virtually no risk of large sinkholes opening up or cracks appearing in the neighbourhood’s streets.
‘Sinking on that scale over a prolonged period of time could be quite significant especially if looking at subsidence bowls where adjacent areas of land are sinking at different rates’, he said. ‘However in this case, the subsidence is most likely caused by underground works and associated ground-water extraction.’
The Northern Line extension is due to fully open in 2020 and forms a continuation of the Charing Cross branch of the line. The works, which are taking place between Kennington and Battersea, will feature two new stations. Nine Elms will be the closest stop for the new United States embassy and Battersea Power Station will be the final stop on the line.
While the news that the entire neighbourhood of Kennington has sunk may come as a shock, it’s unlikely to be long-lasting. The drilling works are now complete and as the ground-water begins to recover, the land should return to normal.