Hazards Tracin Hoz-e Soltan Playa through Investigating Chaos in Micro-landforms

Human intervention in intensification of natural hazards is a concern for researchers. Recognizing the response of morphological phenomena to human activities is not traceable in all phenomena. Small landforms could capture short-term changes caused by human interventions and react to them. Playa are among the areas in which micro-landforms changes can be traced monthly or permanently. Playa are the remaining parts of Quaternary rainy lakes which most of them currently drain the arid and semi-arid basins. The changes in water content and human interventions have created Morphogenesis changes in playas which are identifiable in micro-landforms. In this research, Hoz-e Soltan with 330 km area in north of Qom Province is studied by Fractal modelling in order to determine the prevailing pattern on microforms. Research data were collected through field observations. In order to measure geometrical fractals, field observation was conducted in spring 2014 and 102 clay microforms were selected in May and October. 73 well-developed microforms were selected randomly and their dimensions were calculated and plotted accurately. The results showed that the calculated DAP based on circumference-area Fractal model includes values from 1.5 to 2.5 which suggests the intensity of clay microforms change and their tendency to the increase of chaos and irregularity. Logarithmic diagram of fractal model also shows that there is a linear relationship between circumference logarithm and landform logarithm, so that the resulted correlation coefficient R2 is larger than 0.98. Increase of chaos in Hoz-e Soltan playa implies its reaction to human intervention in harvesting mineral resources and irregularity in water content which could create hazardous results in this part of our country.