Stratigraphic simulations using fuzzy logic to model sediment dispersal

The purpose of this paper is to report on our preliminary two- and three-dimensional stratigraphic simulations that use fuzzy logic to model sediment production, sediment erosion, sediment transport and sediment deposition. Fuzzy logic offers a robust, easily adaptable, and computationally efficient alternative to the traditional numerical solution of complex, coupled differential equations commonly used to model sediment dispersal in stratigraphic models. Fuzzy logic is based on the concept of fuzzy sets, and, since the 1980s, fuzzy logic has been successfully applied in virtually all areas of engineering and computer sciences, as well as in areas of decision making, optimization, management, and operations research. Fuzzy logic is also rapidly being assimilated into the sciences and, since it is capable of utilizing both “hard” data and “soft” qualitative statements, fuzzy logic naturally lends itself to applications in the Earth Sciences. Here we first compare two-dimensional simulations of reef growth: one based on step-wise solution of a partial differential equation and one in which an elementary fuzzy logic system is employed. The two simulations produce identical results. We then present three fully three-dimensional models: (1) a simulation of the last 200,000 of sedimentation in Death Valley, CA; (2) a simulation of sedimentation on the Great Bahama Banks west of Andros Island during the latest 10,000 years of sea level rise; and (3) a hypothetical delta and floodplain under varying regimes of sea level change. The results of the first two models match surface and subsurface data from Death Valley and the Great Bahama Bank to a remarkable degree even though the models are in preliminary stages. Moreover, the hypothetical deltaic simulations also produce remarkably complex and realistic cross-sections. Thus, our preliminary modeling suggest that the utility of fuzzy logic in stratigraphic simulations may be profound.