## 2 Methods and Data
### Data Selection  
The strong-motion data used in this research were obtained from the Turkiye Strong-Motion Acceleration Records Database and Analysis System (website: [[https://tadas.afad.gov.tr/](https://tadas.afad.gov.tr/)]([https://tadas.afad.gov.tr/](https://tadas.afad.gov.tr/)) (accessed on 4 April 2023)). The Pazarcik earthquake triggered 379 strong-motion stations across Turkiye and Cyprus, with the farthest station located 635 km from the epicenter. The epicenter location and the distribution of triggered stations are shown in Figure 1. Each station's records of two horizontal components from the same set were treated as two separate records and were collectively referred to as horizontal records. In total, 1137 acceleration time histories were collected from 379 stations in the east-west, north-south, and vertical directions. After carefully examining the waveforms, 169 records with incomplete time histories or recording errors were removed. Because records with very small peak accelerations have limited practical significance for engineering seismic research, a further 323 records with peak accelerations of less than 3 gal were excluded. As a result, a total of 451 horizontal strong-motion records and 194 vertical strong-motion records were employed for statistical analysis. To investigate the attenuation characteristics of different site categories, we collected the foundation reports of relevant stations. According to the values of the equivalent shear wave velocity (Vs30) obtained from some reports and the associated site information descriptions, they were converted into commonly used site categories in engineering practice in China. Referring to the literature [17], the Vs30 values were converted into the following site categories in China: Class I (Vs30 \(>\) 550 m/s), Class II (265 \(<\) Vs30 \(\leq\) 550), Class III (165 \(<\) Vs30 \(\leq\) 265), and Class IV (Vs30 \(\leq\) 165), with Class II having a wide range of Vs30 values. The data of 144 stations with site category information are presented in Table 1, which includes the fault distance, east-west-corrected horizontal PGA, and Vs30 for each station. A total of 451 horizontal ground motion records were selected, out of which 280 records had known site conditions. Among these, there were 76 horizontal records from Class I sites, 186 records from Class II sites, and 18 records from Class III sites. No records from Class IV sites were included. When fitting the attenuation relationship, the fault distance was used as a distance parameter. The calculation method of the fault distance was as follows: the surface rupture zone of the Pazarcik earthquake in Turkiye was taken as the projection of the causative fault on the Earth's surface. The latitude and longitude coordinates of multiple survey points of the surface rupture zone were connected to form a surface rupture line. The distance between each station and the segments of the surface rupture line was calculated based on their respective latitude and longitude coordinates, and the minimum value was taken as the fault distance, denoted as Rrup (km). The strong-motion records were grouped according to the site conditions and fault distance. The distribution of strong-motion records is presented in Table 2. From Table 2, it can be observed that within the fault distance range of less than 60 km, 92 horizontal and 46 vertical strong-motion records were obtained. Among them, there were only two horizontal and one vertical strong-motion records for Class III sites. The distribution of samples in different distance ranges was uneven because of the limited number of strong-motion records in Class III sites. Fitting attenuation relationships specifically for Class III sites resulted in significant errors.