Investigation of the engineering bedrock with geophysical studies in Izmir metropolitan area

While safe building design against earthquake is performed, the soil-bedrock model must be constructed. In this thesis study, the soil-bedrock model has been done to obtain information about the work required. The main basic parameter used in soil-bedrock model is the S-wave velocity. S wave velocity along the necessary in order to obtain the investigation depth (the use of specific methods in the study area) is needed. If the bedrock depth is less than 30 meters the Vs30 speed is based. Vs30 speed value in obtaining, Multichannel Analysis of Surface Wave method (MASW) and borehole seismic method (down-hole) is used successfully. If the depth of investigation is more than 30 meters, S wave velocity depth profiles (including bedrock) must be defined instead of Vs30. In this condition, based on the depth of the necessary investigations requires the use of appropriate methods. For an average depth of 50 meters MASW and borehole seismic studies are available. For deeper studies, borehole seismic methods and array microtremor methods (SPAC) is used. Quasi transfer spectra can be calculated by the bedrock models. In this study, performed to define the soil-engineering bedrock model, in a selected pilot area around Izmir Bay the single point microtremor measurements and SPAC with MASW and Down-hole seismic studies were made. After the evaluation of the Microtremor measurements, observational Quasi Transfer Spectra (HVSR) have been obtained. The S wave velocity depth profiles were calculated from SPAC and MASW studies. To optimize the S wave velocity depth profiles, the degree of matching between the theoretical and observational calculated Quasi Transfer Spectra were investigated. In addition, to calculate get information about the deformation changes, between the engineering bedrock and the surface in order, Nakamura damage index coefficients are. As a result, engineering bedrock depth varies between 150-300 meters in this study area. Because of the range is so wide, making regional definition is not recommended. Nakamura damage index coefficients in the study area increase towards the sea and in zones of thickness of the soil is observed to rise. In this case, the soil in these regions elastoplastic and/or plastic behavior characteristics are likely to show.