A Study of the Factors Affecting the Occurrence of Sinkholes in Abarkouh Plain and Making Maps of Areas at Risk

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Abstract

Sinkholes are holes in  limestone ground or other soluble rocks. These holes are formed in almost cylindrical or  cone shapes, and their average size is around three meters. Various natural and human factors have played an important role in the formation of this phenomenon Occuring gradually, sinkholes may not have the same  costly and destructive effects and consequences as floods or earthguakes. The city of Abarkuh, located in the South West of Yazd province, includes areas that are faced with the problem of sinkholes. In recent years, the occurrence of sinkholes in the two villages of Faizabad and Horok around this  city has caused significant damages to farming land as well as equipment. This study aims to find out about the areas prone to sinkhole occurance in the future and provide suggestions as to lessen damages. To evaluate the factors influencing the occurrence of sinkholes and to predict the risk of this occurrence in these areas, GIS  and fuzzy logic were used respectively. For modeling, nine criteria were chosen as the main influetial ones. Then, each layer got fuzzy using fuzzy membership functions available in geographic information system (Gis10). The results of this model generally regard about 32 percent of an area of about 17 sq km that faces a high risk of sinkholes. The area  is mainly located in  the center of the county. Also, 13 percent of this area, 7 square kilometers, is less potential for sinkholes.
 

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