# A New Ground-Motion Prediction Model for Shallow Crustal Earthquakes in Turkiye
## 2 Database and Selection Criteria
It is confirmed that, during the 2006-2016 overlap period, SMD-TR contained 3333 records, whereas ESM had only 1065, further validating the selection process. A summary of the two databases is given in Table 1. The prepared flatfile consists of metadata related to distance parameters and strong-motion waveforms, along with seismic source and site information. The locations of the strong-motion stations (957) of TR-NSMN, whose data were used in the present study, are shown in Figure 1.  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Database Source** & **Abbr. ** & **Event Range** & **Number of Events** & **Number of Records** & **Magnitude Range (\(M_{W}\))** & **Distance Range (\(R_{JB}\))** & **SoF** \\ \hline Engineering Strong-Motion Database & ESM & 1976–2016 (2006–2006) & 554 & 1736 (671) & 4.0–7.6 (1065) & 0–349 & SS: 938 \\ \hline Updated Strong Motions & \multirow{2}{*}{SMD-TR (2006–2016–2023)} & \multirow{2}{*}{554} & \multirow{2}{*}{1149} & 18,437 (333) & \multirow{2}{*}{4.0–7.8} & SS: 8472 (350) & SS: 9049 (15,104) & SS: 916 (15,104) & SS: 938 (15,104) & SS: 938 (15,104) & SS: 664 (15,104) & SS: 938 (15,104) & SS: 664 (15,104) & SS: 13  
The combined database contains the parameters of 1565 earthquakes with magnitudes ranging from 4.0 to 7.8 (\(M_{W}\)) that occurred in Turkiye and its vicinity between 1976 and 2023. The earthquakes are typically characterized by shallow crustal events with focal depths of up to 35 km. To minimize the inclusion of intermediate-depth subduction earthquakes, which are prevalent in the Eastern Mediterranean, 557 records from earthquakes with focal depths exceeding 35 km were excluded from the analyses. Moderate-magnitude events in the dataset generally occurred in the western part of Turkiye. Seismic events in these regions occur along the strike-slip NAF and the extensional regime (normal faults) of Western Anatolia. Large-magnitude earthquakes occurring on the EAF, where strike-slip events dominate, are generally events that have occurred in the last 20 years. The distribution of the epicenters of earthquakes with available focal mechanism (moment tensor) solutions used in the study is shown in Figure 2. In recent years, with the increase in the number of accelerometer stations in Turkiye and the occurrence of many major earthquakes, there has been a significant rise in the number of acceleration records. The cumulative increase in the strong-motion records between 1976 and 2023 (February) is given in Figure 3. For the seismic events used in the study, information from both national and international seismological organizations, as well as literature data, is checked, and earthquakes are classified according to the tectonic regime. Records were grouped into three fault types (SoF) based on focal mechanism solutions. In the database, there are 9410 records (47%) for strike-slip (\(SS\)) events, 9713 records (48%) for normal-slip (\(NS\)) events, and 1050 records (5%) for reverse-slip (\(RS\)) events (Figure 4). The data distribution shows a similar number for \(SS\) and \(NS\) events; however, both are significantly greater than the number of \(RS\) events. As source-to-site metrics, for earthquakes with magnitudes \(M_{W}\geq 5.5\), and a real fault geometry (with fault plane solutions), we used the closest horizontal distance to the surface projection of the fault plane (\(R_{JB}\)), calculated using finite-fault distance metrics. However, the epicentral distance (\(R_{epi}\)) was calculated for each record. For smaller events (\(M_{W}<5.5\)), since the differences between \(R_{epi}\) and \(R_{JB}\) are negligible, the point source distance was  
Figure 2: A map of Turkiye showing the locations of events used in calibration with focal mechanism (beach ball) solutions. The color of the beach balls denotes the faulting type: red, black, and blue beach balls correspond to normal-slip, thrust-slip, and strike-slip faulting types, respectively. considered.