Formation of Hot Water Springs in Sri Lanka

As a wonderful gift of nature, several hot water springs occur in Sri Lanka, though it is not situated within a very active tectonic zone of the earth. The present research was conducted to model the formation of hot water springs in Sri Lanka based on geological and tectonic settings by using geological, geophysical and remote sensing techniques. It is found that the major boundary between Highland Complex and Vijayan Complex show multiple thrust planes and shear zones showing imbrecated lithological slices of both Highland Complex and Vijayan Complex. Other than the ductile structures, brittle fractures, joints and fault planes extend as mega lineament for several kilometers. These lineaments produce good secondary aquifer conditions with adequate porosity. The surface mapping and geophysical evidence of the lineaments show that they are very deep and interconnected. Thus it is proposed that structurally controlled hot water springs in Sri Lanka are associated with deep geologically weak zones of fracture or fault systems within the thrust boundary which shows some neo-tectonic activities.