## 3 Comparison of Earthquake Parameters  
There are many significant parameters for structural analysis under earthquake risk [45]. Seismicity elements are among these parameters. Briefly, these elements are defined as local soil conditions, fault/fault groups and their characteristics, and earthquakes at historical and instrumental periods [46; 47; 48; 49; 50; 51]. These parameters vary based on different geographic locations. It is possible that an earthquake will cause more damage to structures under a soft or weak soil condition [52; 53; 54]. Seismic sources, seismic records, and far and near-fault records have a significant role in the seismic vulnerability of structures [55; 56; 57]. The reverse seismic source produces higher vulnerability than the vulnerability of the structures subjected to seismic records from strike slip fault [58]. Hence, the determination of these mentioned-above parameters is vital for near-future plans of engineering structures in the Marmara Region due to the active tectonic existence of high industrial facilities, population density, and high earthquake potential of the region. The Turkish Earthquake Hazard Map obtained from the updated TBEC-2018 is shown in Figure 3. Additionally, the studied provinces are also given. This image map indicates the PGA values, which are expected to be reached or exceeded with a probability of 10% within 50 years, equivalent to the return period of 475 years. PGA is the most widely used parameter for intensity measures (IMs) [59; 60]. The IMs parameters of ground motion are presented as a function of magnitude, distance from the source to the recording station, faulting mechanism, and site class [61]. The PGA values where the yellow colors are dominant show relatively low-risk regions (below 0.1 g), while moderate-risk zones (0.1-0.25 g) are identified from yellow to orange colors, and a red scale represents high-risk zones (more than 0.3 g). The high earthquake potential of the Marmara Region mentioned previously is seen on the map. Four different earthquake ground motion levels identified in the TBEC-2018 are listed in Table 1. PGA and PGV values that were calculated based on TEHMIWA for different exceedance probabilities in 50 years for all provinces are presented in Table 2. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Earthquake Level** & **Repetition Period (Year)** & \multicolumn{2}{c}{**Probability of**} & **Description** \\  & & **Exceedance (in 50 Years)** & \\ \hline DD-1 & 2475 & 2\% & Largest earthquake ground motion \\ DD-2 & 475 & 10\% & Standard design earthquake ground motion \\ DD-3 & 72 & 50\% & Frequent earthquake ground motion \\ DD-4 & 43 & 68\% & Service earthquake movement \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Earthquake ground motion levels [6]. Figure 3: Turkish Earthquake Hazard Map [25] and the studied region. In the study, ZC local soil class that given in TBEC-18 was chosen as the local soil class to determine the earthquake and structural parameters. The characteristics of this soil type (ZC) are given in Table 3.  
Among the innovations in TBEC-2018 is the local soil coefficients. The local soil effect coefficient \(\mathrm{F_{S}}\) and the local soil effect coefficient for a 1.0 s period (\(\mathrm{F_{1}}\)) for the ZC soil type are given in Tables 4 and 5, respectively. Information about selected local soil class (ZC), earthquake ground motion level (DD-2), and geographic location were entered as input data in TEHMIWA. This process was carried out separately, and earthquake parameters were obtained for each geographic location. Two dimensionless map spectral acceleration values started to be used with the updated code such as short period map spectral acceleration coefficient for the period of 0.2 s (\(\mathrm{S_{S}}\)) and map spectral acceleration coefficient for the period of 1.0 s (\(\mathrm{S_{1}}\)) which were obtained from TEHMIWA. Map spectral acceleration coefficients are obtained separately for different ground motion levels.