Stratigraphic simulations using fuzzy logic to model sediment dispersal

The purpose of this paper is to report on our preliminary two- and three-di mensional stratigraphic simulations that use fuzzy logic to model sediment production, sediment erosion, sediment transport and sediment deposition. F uzzy logic offers a robust, easily adaptable, and computationally efficient alternative to the traditional numerical solution of complex, coupled diff erential equations commonly used to model sediment dispersal in stratigraph ic models. Fuzzy logic is based on the concept of fuzzy sets, and, since th e 1980s, fuzzy logic has been successfully applied in virtually all areas o f engineering and computer sciences, as well as in areas of decision making , optimization, management, and operations research. Fuzzy logic is also ra pidly being assimilated into the sciences and, since it is capable of utili zing both "hard" data and "soft" qualitative statements, fuzzy logic natura lly lends itself to a plications in the Earth Sciences. Here we first compa re two-dimensional simulations of reef growth: one based on step-wise solut ion of a partial differential equation and one in which an elementary fuzzy logic system is employed. The two simulations produce identical results. W e then present three fully three-dimensional models: (1) a simulation of th e last 200,000 of sedimentation in Death Valley, CA (2) a simulation of sed imentation on the Great Bahama Banks west of Andros Island during the lates t 10,000 years of sea level rise; and (3) a hypothetical delta and floodpla in 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 Ba hama Bank to a remarkable degree even though the models are in preliminary stages. Moreover, the hypothetical deltaic simulations also produce remarka bly complex and realistic cross-sections. Thus, our preliminary modeling su ggest that the utility of fuzzy logic in stratigraphic simulations may be p rofound. (C) 2001 Published by Elsevier Science B.V.