Introduction to modeling terminology and concepts

Initial development of shallow subsurface geological models was mostly related to assessments of groundwater resources or mitigation of sources of subsurface pollution. Geological models have become an integral part of major civil engineering design, construction, and management projects. Geological survey organizations exist as both national geological surveys and regional state or provincial geological surveys. Analyses of geological hazards, the stability of underground excavations, and groundwater and surface water interactions involve complex time-varying processes, and so are 4-D. Geographic information systems evolved to provide limited 3-D display capabilities, such as contoured maps or isometric views by treating elevation as a dependent variable, or attribute, of spatial location. During 1988 and 1989, critical performance/cost thresholds were crossed, and the initial commercial 3-D geological modeling software products were announced and demonstrated. The chapter also presents an overview on the key concepts discussed in this book.