Identification of karstic zones using RS & GIS method, Fuzzy logic and AHP in Neka catchment, Mazandaran, Iran

Abstract

This study focuses on identifying zones and karstic phenomena using the RS & GIS method along with Fuzzy logic integration and the Hierarchical Analysis Process (AHP) in part of Neka catchment in Mazandaran province in the north of Iran. In this research, eight lithological factors, density and distance from the fractured lineaments, density and distance from the drainages, topographic slope, precipitation and vegetation status, were extracted from satellite and archival data as well as field data. Then these factors which affect karst formation and development are fuzzy and are weighted by the AHP method and integrated with T-norm, T-conorm (S-norm) and Compromise Operators. The results were processed by using software such as ArcGIS, ENVI, RockWorks, IDRISI, Expert Choice and PCI Geomatica, which were evaluated based on fieldwork. The results of this study show that most karst developments occurred in Lar Formation with the upper Jurassic. According to field visits, the best and most appropriate output for fuzzy layers integration are the use of a compromise operator in the range of 0.9 to 0.95. In spite of the suitable ability of Landsat 8 bands to extract lineaments due to vegetation status and other environmental conditions, the use of DEM was also necessary. This study shows that the use of new remote sensing and GIS technology, combined with Fuzzy logic and AHP, increases accuracy and speed and reduces cost in karst studies.