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  • http://hdl.handle.net/10402/era.27628
  • Geostatistics with location-dependent statistics
  • Machuca-Mory, David Francisco
  • English
  • Geostatistics
    non-stationarity
    Local distributions and variograms
    Locally stationary kriging
    Locally stationary Gaussian simulation
    Geological modelling
    Natural resources evaluation
  • Aug 12, 2010 9:37 PM
  • Thesis
  • English
  • Adobe PDF
  • 6192420 bytes
  • In Geostatistical modelling of the spatial distribution of rock attributes, the multivariate distribution of a Random Function defines the range of possible values and the spatial relationships among them. Under a decision of stationarity, the Random Function distribution and its statistics are inferred from data within a spatial domain deemed statistically homogenous. Assuming stationary multiGaussianity allows spatial prediction techniques to take advantage of this simple parametric distribution model. These techniques compute the local distributions with surrounding data and global spatially invariant statistics. They often fail to reproduce local changes in the mean, variability and, particularly, the spatial continuity, that are required for geologically realistic modelling of rock attributes. The proposed alternative is to build local Random Function models that are deemed stationary only in relation to the locations where they are defined. The corresponding location-dependent distributions and statistics are inferred by weighting the samples inversely proportional to their distance to anchor locations. These distributions are locally Gaussian transformed. The transformation models carry information on the local histogram. The distance weighted experimental measures of spatial correlation are able to adapt to local changes in the spatial continuity and are semi-automatically fitted by locally defined variogram models. The fields of local variogram and transformation parameters are used in locally stationary spatial prediction algorithms. The resulting attribute models are rich in non-stationary spatial features. This process implies a higher computational demand than the traditional techniques, but, if data is abundant enough to allow a reliable inference of the local statistics, the proposed locally stationary techniques outperform their stationary counterparts in terms of accuracy and precision. These improved models have the potential of providing better decision support for engineering design.
  • Doctoral
  • Doctor of Philosophy
  • Department of Civil and Environmental Engineering
  • Fall 2010
  • Deutsch, Clayton V. (Civil and Environmental Engineering)
  • Askari-Hasab, Hooman (Civil and Environmental Engineering)
    Leung, Juliana (Civil and Environmental Engineering)
    Sanchez-Azofeifa, Arturo (Earth and Atmospheric Sciences)
    Chilès, Jean-Paul (Centre de Géosciences, MINES, ParisTech)