# A New Ground-Motion Prediction Model for Shallow Crustal Earthquakes in Turkiye
## 2 Database and Selection Criteria  
One of the most critical decisions in developing GMPMs is determining which data to include or exclude from the regression analysis. The accuracy of the estimated ground motion is directly influenced by the characteristics of the database. Ideally, uncertainties (both epistemic and aleatory) in the dependent and independent variables should be minimized. However, due to the nature of earthquakes, it is not possible to completely eliminate these errors and uncertainties. Sometimes, the required parameters may be missing or not of the desired quality. For example, the absence of an in situ measured \(V_{530}\) profile for the site classification of the stations is a common problem. Limiting the study to stations with only the measured \(V_{530}\) may cause the dataset and sample to be reduced, which may also affect the representativeness of the prediction models. As in this example, a good balance should be established between filling in the gaps with alternative methods (e.g., spectral ratios, field observations, topography, etc.) and being restrictive by eliminating data. The data used in this study were sourced from two different ground-motion databases. The first dataset was obtained from the ESM ([[https://esm-db.eu/#/home](https://esm-db.eu/#/home)]([https://esm-db.eu/#/home](https://esm-db.eu/#/home))) database [24], which was supported by the EPOS EU project (Grant Agreement 676564) in which AFAD is involved; it was developed under the coordination of the ORFEUS strong-motion management committee. This database comprises strong-motion waveforms from earthquakes with \(M_{\rm W}\geq\) 4.0, recorded in the European-Mediterranean region since 1969. The acceleration time series in the ESM database were processed following the general procedure scheme described by [29]. In this database, the data recorded in Turkiye only include the years between 1976 and 2016. The second database we used is the Updated Strong Motions Database of Turkiye (SMD-TR) [30]. The database is provided by the portal compiled and shared under the research-oriented website (DesignSafe, last accessed, 12 August 2024, [[https://doi.org/10.17603/ds2-f21x-s189](https://doi.org/10.17603/ds2-f21x-s189)]([https://doi.org/10.17603/ds2-f21x-s189](https://doi.org/10.17603/ds2-f21x-s189))). It was regularly updated until 2025 with funds provided by TUBITAK (last accessed, 20 November 2024). This database consists of 9244 earthquakes with magnitudes of 3.0 \(\leq\) M \(\leq\) 7.8 that occurred between 1976 and 2023. The data source consists of 95,890 three-component waveforms recorded exclusively by the 1022 stations of TR-NSMN. The published version covers events up to 28 February 2023, including the main shocks and the majority of the aftershocks of the 6 February 2023 Kahramanmaras earthquakes. A data-processing algorithm is developed to apply appropriate filters to eliminate low- and high-frequency noise from the records and to calculate strong-motion parameters. A manual processing scheme is preferred for waveforms recorded from large events, while an automatic processing algorithm is used for events with small magnitudes (M \(<\) 5.5) [29]. The data-processing scheme applied here follows the same procedure as outlined by [25]. The flatfile used in the study is extracted from these two data sources (ESM and SMD-TR). To ensure that records from both the ESM and SMD-TR databases (1976-2016) were not counted twice, a rigorous and controlled merging process was implemented. First, the datasets were standardized, color-coded, and assigned unique Record IDs. A \"Record-Name\" column was defined using timestamps and station codes to facilitate sorting. After merging, records were sorted chronologically, and overlapping entries from the same station were identified. When duplicate records existed, preference was given to ESM, as its data were manually processed. This meticulous approach ensured accuracy and eliminated redundancy.