NATURAL AND MAN-MADE ANALOGUES: USES AND MISUSES

Geologic, archaeologic and engineering based analogues are being called upon to support long-term predictions of future performance of critical facilities. Efforts to isolate nuclear and other toxic and hazardous wastes provide examples. Electric, sandtank and other analogues, later sophisticated numerical flow and transport models provided powerful tools for forecasting the responses of complex geologic and hydrologic systems to natural and man-induced stresses that included more realistic complexities. Despite the power of these computational facilities, post-audit results were not always flattering. Either features, processes, and events that influence or allow prediction of the response of natural and engineered systems to induced stresses were inadequately understood, or critical more dominate features influencing the interaction of these systems were overlooked during site characterization and engineering analysis. The Teton Dam failure comes to mind. Forecasting the response of natural systems and engineered facilities influenced by still more complicated coupled processes, such as the interaction of mechanical, thermal, geochemical, biological processes, adds to this challenge as does the open ended time dimension. Doubts regarding the level of investigator confidence and uncertainties to address such complexities continue to increase together with the public's skepticism regarding the integrity and credibility of these researchers. Analogues can provide an independent means for building confidence when analyzing such complex phenomena provided that individual elements can be clearly explained and matched one for one with the coupled processes being investigated.