Stochastic approach to investigate the radon time series and geo-scale relationship in the MCT region of Uttarakhand, India

The study evaluates the long term measures of radon (²²²Rn) concentrations in soil and water samples. To explore the ²²²Rn spatio-temporal variation and its geospatial correlation the stochastic modeling approach. Prolonged inhalation of ²²²Rn above certain levels poses health risks, and its spatio-temporal variation could potentially signal impending earthquakes. This study aimed to establish a relationship among predicted ²²²Rn concentration and daily radon measurements from continuous source seasonality, stationarity, and long-range memory structures using specifically the Autoregressive Integrated Moving Average (ARIMA) model for seismic activity to frame early warning system. Power spectral analysis, leveraging continuous wavelet transformation, reveals distinct seasonal patterns with a three-year periodicity. Stationarity is assessed using the Dickey-Fuller test, while long-range dependencies are indicated by the decay patterns of the Hurst exponent and the autocorrelation function. Hypothesis and model outcomes reveals that the established foundational mathematical and statistical relationship between ²²²Rn concentrations and earthquake events, particularly in the central Himalayan regions. The ²²²Rn daily concentration over the Main Central Thrust (MCT) Zone and earthquake events in the Tehri Garhwal, Uttarakhand India were analysed for the period 2004-06. A correlation between soil radon gas and micro-seismic activity was observed. Findings suggest that radon concentration supports the long memory hypothesis leading to a slow, non-exponential decay with geo-scale dependence and can be influenced the predictability of early warning systems at micro-scale. Geo-scale level study suggests that the shear-controlled uranium mineralization of significant dimension and grade is preliminarily influenced by chlorite-sericite schist's type of setting (Pokhri area of Chamoli Gahrwal) and by granite gneisses in Brijranigad area, Tehri district, Uttarakhand India. Uranium (²³⁵U) and Thorium (⁹⁰Th) distribution throughout various types of rocks, soil, and water host different stages U(⁺4), U(⁺6) and similarly the primary source of radon gas is found in these environment settings. (author)