Analysis of subsurface soil radon with the environmental parameters and its relation with seismic events

This study reports continuous measurements of subsurface soil radon as well as environmental parameters for a period of three years. The survey was carried out along the active fault area in the Indo-Myanmar subduction zone in the north-eastern part which lies in the highest seismic zone of India. The wavelet-based decomposition of the environmental parameters was done using discrete wavelet transformation technique. The denoised environmental parameters by discrete wavelet transformation technique was fed as the inputs to the MLR (multiple linear regression) and MLP (multilayer perceptron) models. Residual radon was calculated and correlated with nearby seismic events. Many events of magnitude greater than or equal to 5 have occurred in the investigation area. It was possible to successfully correlate one event with the anomalous variation in soil radon. The correlated event was the only one with the shallow epicentral depth indicating that the investigated area has undergone a shallow rock fracturing due to the stress generated before the occurrence of the seismic event.