'Abnormal' subsidence in Tseung Kwan O posed no immediate danger to residents, the Government said last night. Reports said yesterday a four-hectare plot of land had been subsiding faster than normal, forcing the Housing Authority to suspend taking over the plot. The Works Bureau confirmed that unusual settlement had been recorded in some areas of the new town, which lies on reclaimed land. Affected areas include the town centre and Tseung Kwan O Industrial Estate. 'Ground settlement is a normal phenomenon in newly reclaimed land but in the case of Tseung Kwan O, the amount of settlement is greater than expected - about 850mm compared with the normal amount of 150 to 300mm,' a bureau spokesman said. An investigation into the cause of subsidence by the Territory Development, Drainage Services and Environmental Protection departments is continuing. 'So far we have found no evidence of problems with either the design or the quality of construction of the reclamation,' a Works Bureau spokesman said. 'The unusual settlement may be caused by a number of factors, including changes in ground-water levels which are affecting deeper soil layers that do not normally settle.' Drainage Services Department senior engineer Lee Kui-biu said if the ground settlement continued, it would affect the pavement and underground facilities of the reclaimed area. 'Ground settlement is very often related to the loss of ground water. But what has caused the ground water level to change will need a detailed study,' Mr Lee said. None of the buildings within the town centre were at risk because they were built on piled foundations, the Works Bureau said. Reclamation for Tseung Kwan O began in 1983 and it was originally planned to accommodate an eventual population of 355,000. This later was revised to 520,000 by 2011.