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Geostatistics
Laboratory

My research focuses on the following directions:

(1) The development of new geostatistical methods and their applications in mineral resources exploration, petroleum reservoir simulation, environmental monitoring, and GIS mapping functions.

(2) The application of geostatistical and statistical physics techniques in stochastic hydrology.

(3) The investigation of the impact of heterogeneity on the mechanical properties of porous materials such as advanced ceramics.

(4) The investigation of the probability laws of earthquake return times as well as applications of geostatistics to the analysis of correlations between seismic events on different faults.

1. Geostatistics

In a nutshell, Geostatistics aims to analyze the spatial structure of natural processes based on scattered data and to use the information for the purposes of estimation, interpolation and simulation at locations (or times) that are not accessible for measurement.

More specifically, I am currently interested in the following topics:

  1. Development of Spartan Spatial Random Field Models for geostatistical applications. In the spirit of the Gibbs-Markov random fields, I have constructed interaction-based random fields, which I named Spartan to emphasize their compact specification compared to the experimental variogram (Hristopulos 2003b; 2004b, Hristopulos and Elogne 2007; Hristopulos and Elogne, 2009).
  2. Development of SSRF predictors based on local error definition (Hristopulos, 2005a) and maximization of the conditional posterior distribution (Hristopulos and Elogne, 2009).
  3. Systematic methods for identifying geometric anisotropy (Hristopulos 2002; 2004a; Chorti and Hristopulos, 2008; Spiliopoulos et al., 2011).
  4. Formulation of non-Gaussian Spartan random field models based on spin models from statistical physics (Zukovic and Hristopulos, 2009a, 2009b).
  5. Current topics of interest include the extension of the Spartan random fields to space - time and the development of constrained simulation methods that can benefit from the computational efficiency of Spartan random fields.
  6. Application of SSRF models in automatic mapping of environmental pollutants, ecology, environmental risk assessment, financial time series and mineral resources estimation. (Elogne et al. 2008, Moustakas and Hristopulos, 2008; Moustakas et al. 2007; Zukovic and Hristopulos, 2008; Hristopulos and Elogne, 2009).
  7. Development of a non-parametric method for the estimation of geometric (elliptic) anisotropy from gridded and scattered data (Chorti and Hristopulos, 2008; Spiliopoulos et al. 2001). Matlab code is available at (Anisotropy Code).    

2. Hydrology

My efforts focus on modelling the effects of spatial variability in porous media at various scales, and especially in the calculation of coarse-grained parameters of transport properties such as fluid permeability and macro-dispersivity.

Another interest is the space-time modelling of the water table depth using geostatistical approaches.

My specific interests include the following topics:

  1. The application of renormalization group (RG) methods in the calculation of effective parameters (Hristopulos and Christakos, 1999; Hristopulos, 2003a).
  2. Investigating the effects of anisotropy on the fluid permeability tensor.
  3. Connections between morphological and stochastic models of porous media.
  4. The development of new methods for modelling the heterogeneity in porous media that could incorporate higher-order structural information.
  5. The application of space-time geostatistical methods to the monitoring and prediction of the groundwater level in the Messara valley of the island of Crete.

3. Ceramic Materials

This work was carried out in collaboration with the Laboratory of Ceramics and Glass Technology, and it was funded by the European project "Activation".

The research continues in collaboration with the laboratory of Physical Metallurgy of the National Technical University of Athens.

My research in ceramics focuses on the following:

  1. Modelling of grain coarsening and coalescence processes in nano-grained ceramic materials, with special interest on the effects of mechanical activation (Hristopulos et al., 2005).
  2. Investigating the impact of structural disorder (i.e., of the complex pore space) on the mechanical properties of the materials (Hristopulos and Demertzi, 2008).

4. Earthquakes

 My work focuses on the probability laws of earthquake return times and applications of geostatistics to the analysis of correlations between seismic events on different faults of the same system.

This work is carried out in collaboration with the post-doctoral fellow Vasiliki Mouslopoulou and is funded by the European Commission FP7 program. For more information check the website of the project "Bridgseismtime".