Calculation of the soil dynamic amplification factor values by using microtremor data: A case study in Izmir (North)

In this study, the distribution of dynamic amplification factor (DAF) values at the study area were obtained by joint evaluation of scenario earthquake parameters that could occur in the study area with single station microtremor data gathered at 112 points. The dynamic amplification factor can also be defined as the ratio of the magnitude of earthquake waves from the bedrock to the ground. Also the DAF value is a parameter that represents the entire spectrum, not a single peak value. The data collected by using single station microtremor method were evaluated by horizontal to vertical spectral ratio (HVSR) technique. The scope of the study is the common interpretation of predominant soil period (PSP), dynamic amplification factor, geology data and topography data of the research area. Dynamic amplification factor values are obtained generally higher than 2 at regions near the sea level that composed of alluvial units. Dynamic amplification factor values which are lower than 2 were obtained at the volcanic rocks located at high elevations. As expected, predominant soil period values are distributed in directly proportional to the dynamic amplification factor at the study area. The smallest amplification value in the study area is 1.20, while the maximum magnification value is around 3. The coincidence of the maximum values of predominant soil period and dynamic amplification factor with the alluvial units where the elevation is low shows that these parameters were obtained in harmony with each other.