Morphotectonic survey of West Lake Urmia region using multivariate spatial analysis

The spatial analysis of Morphotectonic zones and finding an appropriate quantitative method for how to do Morphotectonic studies are the subjects of this research. This kind of studies is one of the basic measures in land use planning. This studies in the research area have not been done accurately and the zonation have been done both qualitatively and visual analysis in the national level without using quantitative analysis and without using specific variables. so that, their results do not match with morphotectogenic facts of the research area. It is difficult to provide an accurate results and interpretation from the vast amount of geomorphic, topographic, geological, accelerometer and hydrologic spatial data without applications of quantitative analysis. The main purpose of this study is to analysis the Morphotectonic factors and then determine the morphotectonic zones of the west part of the Lake Urmia by using quantitative spatial analysis methods. West area of the Urmia Lake is a subject to study area in the present paper. In fact, this area is the main part of Urmia Township place that include the Urmia metropolis and it is the center of the west Azerbaijan province. The mentioned area is from north neighboring with Salmas Township, from east with Urmia Lake, from south to Naghadeh & Oshnaviyeh townships and the west bounded to Turkey country.

The Morphotectonic zones had been mapped by analysis of various geomorphotectonic variables by using different empirical and spatial quantitative methods. The morphotectonic zones formed under the influence of morphotectogenic variables such as various morphotectonic systems (including fracture systems and nodes), complicated geomorphologic and topographical features, geological and hydrological variables. In this study the data related to these variables such as the recorded earthquake system (intensity, depth, density and distance from earthquake centers), the fault system (fracture length, density, distance from fault lines and databased seismicity), Seismic (elevation, gradient and geographic directions), hydrographic network and geological data set with different nature that were used. Data preparation performed as a necessary information layers in the SPSS and Excel software environment. The fuzzy method used for scaling of different variabilities data set. Spatial analysis methods were implemented using techniques such as kriging, Fuzzy, and multivariate cluster analysis of ISO data algorithm in ArcGIS1/9. Finally, above-mentioned variables in different layers analyzed by using ISO data algorithm; as a result, the morphotectonic zones map of the study area were determined.

The results show that there are five different morphotectonic zones as named A, B, C, D, and E in the study area. These zones have different Morphostructure patterns and especial arrangement of morphotectonic elements. the A zone, is coastal plain and conjugate faults, conjugate faults system less seismic events, low Ar index equal to 9 and passive tectonics in the east part of the study area (Urmia Lake west area). The B is mountain land, spatial arrangement of mountains, weakly faults networks, mostgeounits’ variety, with high density of seismic events and the Ar index equal to 17 that show active morphotectonic zone. The C zone is located in the west part of study area with the high mountain land, different faults systems pattern from each other zones and density fault network, most seismic events and the Ar index amount is equal to 26 so it is the high active morphotectonic zone in the area. The D zone mountain high land landform, most geo units variety, rift zone, low faults network but longitudes fault line, relatively low seismicity activity in recently years and the Ar index amount is 11 sothatit’smorphotectonicactive zone. The E zone is located in the north part of the study area, the mountain landform with elevation means is 271 meter; density faults network which especial pattern of faults system like conjugate faults system in northwest - southeast trend and with longitudes fault lines in northeast – southwest trend, relatively low seismicity activity in recently years. The Ar index amount of this zone is 9 so; this shown it is relatively active morphotectonic zone. Result shown that, in present time the fault systems and hydrology derange network processes controls the morphotectonic situation and play an important role in making of morphotectonic zone types and act as a reinforcement of morphology and tectonics conditions.

Considering that in the study area the morphotectonic zoning done both qualitatively and visually approach without using quantitative analysis methods and without certain variables. Therefore, the accuracy of the results and the accuracy of the research was ambiguous. So in this research the ISO data spatial analysis method with the certain morphotectonic spatial variables used in this research. The results shows that ISO data spatial analysis method has higher performance in identifying and determining the morphotectonic zones, also the results shows that good conformity with ground reality. In addition, this method demonstrates a high degree of efficiency in analyzing a large amount of spatial data with different nature, which is not possible with conventional and visual methods.