oa The Algorithm for Statistical Modeling in 3D by Pentamodel of Variogram Using the Example of Rivne Npp Data

In connection with significant growth in the number of natural and man-made disasters, further development of monitoring systems of the geological environment by using modern mathematical approach and newest information technologies becomes relevant. An important component in the environmental monitoring system is local monitoring of such territories, where potentially dangerous objects are located. A complex of geophysical studies was carried out on Rivne NPP industrial area territory. The greatest interests among these important monitoring observations are radioisotope study of density and moisture of soil built along all perimeter of buildings. During these studies, it became necessary to model additional data to the subject of research data, that were obtained by monitoring changes in the density of the chalk strata on the territory of the studied industrial area by using radioisotope methods on a grid that included 29 wells. Such a problem was solved in the work by the method of statistical modeling, which makes it possible to get additional values of observational parameter (a random field of the object of study in a three-dimensional area) at any point in the observation area. At the same time, the average values of the density of the chalk stratum on the territory of the industrial area of the Rivne NPP were modeled by using the model and the “pentamodel” correlation function. Based on the “spectral decomposition”, a statistical model of the distribution of the average density of the chalk stratum in 3D area was constructed and algorithm for statistical modeling using a “pentamodel” correlation function was developed. On the basis of the developed software, the realizations of the density of the chalk stratum on the observation grid of the required detail and regularity was obtained. A statistical analysis of the results of numerical simulation and checking them for adequacy was carried out. When solving the current tasks of geophysical monitoring of the environment, the very important tasks of modeling random fields with various types of correlation functions in the three-dimensional area arise. In previous works, the authors considered correlation functions of the Bessel, Uhittle-Matern, “power” and spherical types, and in this work - of the “pentamodel” type.