Lucknow-based experts of the Geological Survey of India (GSI) have pointed out a detailed study of the underground water characteristics can play a significant role in giving precursory signals of impending earthquakes, even though forecasting of tremors with accuracy still leaves much desired.On the second day of the seminar organised by the GSI to commemorate the centenary of the major earthquake that hit Kangra district, the joint research work of S.N. Pandey, Hemant Kumar and Krishna Singh highlighted that the irregular chemical behaviour of the spring and underground water after an earthquake in an active seismic area suggest a precursory signal.Therefore, regular and systematic monitoring of the springs and underground water samples can be an important parameter for earthquake prediction, they said.The monitoring of radon (a radioactive gas produced by the decay of radium) in ground water on a regular basis was done near Amritsar for six months way back in 1987-88. The anomalous change in radon concentration was recorded on December 23, 1987, with a peak value three times higher than the average.