Remote sensing of discharge of groundwater in collapsed slope by means of infrared thermal imaging

Abstract

This study shows the posibility to quantitatively observe the discharge of groundwater from collapsed slope by remote sensing. In order to remotely observe the discharge situations of groundwater, the temperature of collapsed slope was observed by means of infrared thermal imaging. A slope had been artificially failed by artificial rainfall then a series of thermal images was taken from a distance. Since the collapse occurred at time when the underground temperature was higher than that of ground surface and air, the temperature of collapsed surface immediately after the failure was relatively higher than that of the original ground surface. The collapsed surface then began to be cooled by convection of the air but the temperatures were found to fall down at different rate. Slow rate was observed in some areas and it is considered to be due to the heat transfer from the deep ground to the surface in such areas. According to the observation in this experiment, temperature around one of such areas formed an onemeter-width peak after failure and, the width became to be about 0.5 m at 36 minutes after the failure.