Estimation of Radon Flux Density Changes Using Mathematical α-Model Before and After a Strong Earthquake in Kamchatka

Using data of radon accumulation in a chamber with excess volume at one of the points of the Kamchatka subsurface gas monitoring network, the change of radon flux density due to seismic waves and post-seismic relaxation of the medium is shown. Data in the temporal vicinity of a strong earthquake with Mw=7.0, which occurred in the northern part of the Avacha Gulf on 17 August 2024, were used. The study was carried out using methods of mathematical modeling and inverse problem solving. The change in the intensity of radon transport due to changes in the state of the geo-medium is described using the fractional difference operator of constant real order α. As a result of modeling it is shown that strong seismic impact and subsequent processes in the earth crust led to the change of radon flux in the accumulation chamber. The optimal values of the model parameters were determined, which allowed solving the problems of radon flux density determination. An hereditary mathematical model based on fractional derivative has been applied for the first time to estimate the change of radon flux density under the change of stress-strain state of the medium under strong earthquake conditions. The obtained model curves are in good agreement with real data.