Paper No. 57-9
Presentation Time: 4:00 PM
GEOPHYSICAL PROPERTIES OF SOILS AND EARTHQUAKE SITE RESPONSE ANALYSES IN BUYUKADA/ PRINCES ISLANDS (ISTANBUL) BU USING EERA SOFTWARE
The Princes Island segment is one of three active segments of the Northern Anatolian Fault. Earthquake-soil interaction could be one of the main reason for damage due to the soil amplification and/or liquefaction events. The aim of the study is to present the geophysical/geotechnical properties of the soils with interaction of earthquake ground motion in Buyukada/ Prinkipo (Istanbul). Deterministic and probabilistic analyses are used to evaluate the seismic hazard in the region. Ground motion levels with a probabilistic seismic hazard analysis (for 50 years and exceedance rates (20% and 50%) and deterministic seismic hazard assessment for the region are estimated as M: 7.6 and as M: 6.8. Ground motion levels are estimated by using the probabilistic and deterministic seismic hazard analysis. Buyukada was formed in the last glacial period. Buyukada (Istanbul) geologically has many Paleozoic aged units. Local formations are called as Aydos formation, Kurtköy formation, Gözdag formation, Dolayoba formation, Kartal and Tuzla formation. The alluvial sediments in Buyukada is also important in the seismic behavior during earthquakes. In the study area, geophysical sites are considered according to the geological formations. Working in the field of two different geophysical studies in a total of 19 sites (MASW-MAM and Microtremor) were conducted. For 50 years and two exceedance rates (20% and 50%), design earthquake magnitudes are taken M: 7.6 and as M: 6.8 for the region. For the study area, ground motion levels (acceleration) are estimated by two approaches by using soil conditions (Vs30 values). Soil input for these models are represented by VS30 as min:227 m/s and max: 970 m/s. EERA is a modern implementation of the well-known concepts of equivalent linear earthquake site response analysis. Last phase of our study, EERA software was used to obtain earthquake site response analysis in Buyukada Princes Islands (Istanbul). In this stage, firstly earthquake data was selected as an input motion and procesed. Second stage includes the calculate the compatible strain by using soil profile, material curves. In the last stage, output was calculated the Acceleration/Velocity/Displacement, the Stress/Strain, the Amplification, the Fourier Spectrum, and the Response Spectrum.