Özet:

Site response analyses are seen to be the reliable way of reproducing and predicting earthquake input motions. The analyses are generally performed by adopting equivalent linear or nonlinear approaches solving the problem in time or frequency domains. Instrumented geotechnical downhole arrays, in this regard, are very important as to obtaining earthquake data through the soil deposits. This data can eventually be used to verify the approaches developed for site response analyses. In this study, the input motions of the 24.05.2014 (Aegean) earthquake event recorded at relatively recently installed Atakoy geotechnical downhole array are assessed. Moreover, the recorded input motions at the bottom bedrock level of the downhole array are simulated in the East-West and North-South directions. The site response analyses are conducted based on frequency domain equivalent linear approach. The peak ground acceleration and the spectral accelerations of the predicted input motions are compared with the recorded ones at 70 m, 50 m, 25 m and at the ground surface. The results indicate that the spectral acceleration predictions can be simulated well until the depth of 50 m. At 25 m and at ground surface, the predictions are always greater than the recorded one. However, the predictions still exhibits good indication of actual values in the North-South direction. In terms of peak ground acceleration and shear strain profiles, the predictions display the soil layers featured with different soil properties. The equivalent linear approach appears to be suited reasonably well in site response analysis.

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