The role of structure and geomorphology characteristic in locating and developing of urban plots(the case study: Marivan city)

Natural parameters are the main and determining factors in the physical development of mountainous cities. One of the mountainous cities of Iran, which has physically developed due to these parameters, is the city of Marivan. Marivan is located in the west of Kurdistan province, near the western borders of the country, at a distance of 16 km from Iraq, between 25 degrees and 21 minutes to 35 degrees and 48 minutes north latitude and 45 degrees and 58 minutes to 46 degrees and 45 minutes east longitude. According to the last population and housing census conducted in 2016, it has a population of 151188. The city is located at the starting point of the Marivan-Esfandeghe geological region and is located in the geological-morphological structure of the young Zagros. Therefore, identifying and evaluating the factors influencing the physical development of this city is really important. To do this, the characteristics of elevation, slope and direction of slope, fault, focal points of earthquake occurrence, main and secondary waterways have been used.With regard to its location in northwestern Iran after the eight-year Iran-Iraq war, the study city has experienced significant physical growth and development due to its unique and pristine vital and natural location, which led to the development of this city. Regardless of geological constraints. At present, the city has the potential to benefit from high potentials in the fields of natural and cultural tourism, including (Zarivar Natural Lake, Bashmakh Regional Area, and Border Market, Bilo Plain, Garan Dam, Oramanat and Bazaar for supplying foreign supplies and products. It has become one of the dynamic and active economic-tourism hubs in the west of the country and there is a growing growth and development in the city; therefore, it is inevitable to pay attention to geomorphological factors and determine optimal directions for the development of this city.

According to the National Physical Plan of Region 5, the city is in a relatively high risk of earthquakes, and with respect to available and cited maps, there are 7 sub-faults in the northern part of Marivan and 2 main faults in the western part of the city. For this reason, the physical development of the city is subject to certain restrictions. Marivan is also in a relatively high risk of earthquakes in terms of location in relation to natural hazards.It is an applied research and the method of work is descriptive-analytical and also the fuzzy logic model has been used to evaluate and model suitable areas for development so that each layer is fuzzy according to fuzzy membership functions in GIS environment. And then multiplication and addition operations and different values of fuzzy gamma have been performed on these layers. After overlapping and multiplying the fuzzy layers, a zoning map of the appropriate development route of the city was prepared and divided into 5 classes including completely suitable, relatively appropriate, appropriate, inappropriate and completely inappropriate for the physical development of the city.In the study, library methods, documentary and field studies have been used to collect the desired information and data. To evaluate the optimal development of urban lands, slope indicators, slope direction, fault zoning, main and secondary waterways, erosion, earthquake-prone points in and around the area have been used. The fuzzy and hierarchical analysis process (AHP) was used.

In order to evaluate and weigh the information layers and to determine and score the impact factor of geomorphological indicators affecting urban development while extracting and reviewing the criteria examined in various valid researches and articles, scientific opinions and views of ten experts and specialists were counted and monitored. In order to determine the importance of each of the studied indicators on the location and physical development of Marivan city, the opinions and views of the experts were given based on the superiority of one factor over another and based on expert judgment, scores between 1 and 9 were given. The equivalence of expert scores based on fuzzy method was done by the authors of the article with the help of AHP & FUZZY software.Since 1996, due to the increasing growth and development of the city and the formation of informal settlements, the development of the city has taken place without considering geomorphological considerations, and this has caused the spatial-physical development of Marivan in the northern parts near the existing faults. The development of the city has taken place at relatively high risk.

Summarizing the research, it has been determined that the southern lands of this city have less proportion to the development of the city due to its proximity to Zarivar Lake and its location along the main and secondary waterways and its proximity to the earthquake centers. And to some extent, the East enjoys a higher level of development.