Seismic design codes account for soil conditions and near-surface geology in a very approximate way, namely through the classification of sites into generic classes (based on NSPT or Vs30). However, ground response is more complex. Different soil profiles belonging to the same class may yield different amplification effects (different amplitudes at different frequencies). In addition to that, this effect may not even be the same in all horizontal directions, as is implicitly assumed in typical analyses.

Aim of this thesis to evaluate the ground motion and site effects for the Cretan seismic stations. To do that, empirical methods (e.g. empirical spectral ratios using Fourier and elastic response spectra) will be applied to estimate the near-surface geological effect on seismic ground motion in the frequency domain. Also variety of ground motion prediction equations made for active shallow crustal tectonic regions will be used to do residual analysis and find the difference between the observations and predictions with related site parameters to get a deeper idea on the station by station evaluation on ground motion and site effects. Selected locations of the National Observatory’s seismographic/accelerometric network will be used. Overall station performance will be evaluated by using real data from 2021 Arkalochori earthquake sequence from all possible sites. Results will be the estimation of the variability in response for different soil profiles within the same generic class as per the design code. Also information about the sites will be compared to the results of the analyses and possible discrepancies will be discussed.