Although, recently an algorithms that calls the second wave has been proposed (Ripley, 1996), we are using the so-called Widrow and Hoff algorithm. We have used a modified adaptive linear neuron (Adalin) structure for estimating the temporal variation of radon concentration related to environmental parameters. This enables us to differentiate the changes that are due to phenomena in the earth such as earthquakes from those of environmental parameters. Data reported from a site
at Northern Thailand (Wattananikorn et al., 1998) were employed to apply the method.