Seismic Tomography and Surface Wave Analysis Based Methodologies on Evaluation of Geotechnical Properties of Volcanic Rocks: A Case Study

Economic development, industrialization and dense population in Trabzon City have caused residential construction to increase by 300% in the last decade. The settlement area is mountainous and covered with heavy vegetation. Thus, the steep-sided topography and heavy precipitation means floods and landslides are common and in areas with little flat land. Since the mass movements in some parts of city create an enormous danger for buildings, site selection for residential areas becomes increasingly important. This paper describes geotechnical and seismic properties of Tertiary volcanic rock and establishes the link between these units and construction. In this study, refraction tomography and multichannel analysis surface wave methods were applied in order to seek the best construction site in the residential area. The results of the geophysical study were compared with the borehole applications. A series of geomechnical tests were carried out on the core samples. Following that, statistical correlations were conducted by regression analysis to evaluate relationships between measured parameters. Rock Quality Designation and weathering degree were also determined. The methodology defined in this investigation proves to be an appropriate approach to determine geotechnical properties of the foundation rocks and soils and a proper guide on future geotechnical studies for other cities.