Journal of Spatial Analysis

The consequence of human activities caused destructive and irreversible problems to the original state in the few past decades that has attracted the attention of all walks of life. The sinkholes are one of the mentioned effects in different parts of the planet such as Iran, Hamadan and especially have been happened in Kaboudarahang-Famenin plain. Researchers believe that the most important consequences of the indiscriminate withdrawal of groundwater and illegal wells and the activities of Shahid Mofatteh thermal power plant change the parameters of soil caused appearance sinkholes in that area. All of the geological information, faults, hydrological, elevation, slope, aspect, and land use investigated by topographical geological maps, also digital elevation models and Google Earth image processes used for the study on the extraction and sinkholes due to the numbers and distribution of wells were assigned in GIS software. The results show that the level of groundwater, geology, land use and height of the range are the most effective factors in the creation of sinkholes; but the efficiency of surrounding factors and in somewhere farther from the sinkholes. The construction of Ekbatan dam on the most important river as the main water provider of understudy plains, the development of Hamadan city and changing the surrounding land use in Bahar county to agricultural, prevent from reaching water to the Kabodarahang and Famenin plains as a former and increasing the water demand in downstream is caused numerous sinkholes that was provided with favorable conditions than before (the dissolution of limestone).

Objective: Investigating the occurrence of land subsidence in the country and the extent to which rural settlements are exposed to the phenomenon of land subsidence.
Methods: The present study was based on library surveys and studies, field observations and impressions. Using information received from the National Mapping Organization, a map of the country's subsidence zones and the degree of risk of each zone, including very low, low, medium, high and very high risk, was drawn, and the aforementioned maps were compared with the location of the villages.
Results: According to the analysis of the available data, 302 villages are at very high risk, 768 villages are at high risk, 834 villages are in the medium risk zone, and 573 villages are in the low risk zone. In terms of percentage weight, about 4 percent of the country's villages are at medium to very high risk of subsidence, of which 1,904 villages are at medium to very high risk, and 573 villages are at low risk.
Conclusions: The highest provincial distribution of villages at risk of subsidence in the country with a very high degree is in the provinces of Alborz, Tehran, Khorasan Razavi, Qazvin, Kerman, Golestan and Hamedan, and the highest provincial distribution with a high degree is in the provinces of West Azerbaijan, Isfahan, Alborz, Tehran, Khorasan Razavi, Semnan, Qazvin, Kerman, Golestan, East Azerbaijan, Hamedan and Yazd. Also, the highest provincial distribution of villages at risk of medium-level subsidence is in the provinces of East and West Azerbaijan, Isfahan, Alborz, Tehran, Semnan, Qazvin, Kerman, Golestan, Mazandaran, Markazi, Hormozgan, Hamedan, and Yazd.