# Geotechnical and Structural Damages Caused by the 2023 Kahramanmaras Earthqu in Golbasi (Adyaman)
## 4 Seismicity of Adiyaman Province and General Geology of the Study Area  
On a macro scale, in Golbasi and its surroundings, sedimentary rocks of the Southeast Anatolian autochthonous, developed from the Paleozoic to Tertiary periods, and allochthonous masses related to the Karadut complex from the Kocali-Karadut nappes settled in the region at the end of the Upper Cretaceous are observed. Although it is located on the Southeastern Anatolian autochthonous, volcanic rocks consisting mostly of basalt and pyroclastics in the Late Miocene-Early Pliocene age range are exposed in the study area [50]. In the region located at the northern end of the Southeastern Anatolia autochthonous, the oldest rock units belonging to the autochthonous are the Kestel formation, consisting of late Campanian-Maastrichtian sandstone, shale, and marls. At the top, the Midyat group, which consists of Eocene-Oligocene aged carbonates, unconformably covers the sequence. In the lower part of the Midyat group, there is the Gercus formation, consisting of Early Eocene-aged continental crumbs. Above the Gercus formation is the Hoya formation, consisting of Eocene-aged limestone, and above it is the Gaziantep formation, consisting of Late Eocene-Oligocene aged limestone, clayey limestone, and cher limestone. The Firat formation, consisting of Early Miocene-aged limestones, and the Selmo formation, consisting of Middle-Late Miocene-aged conglomerate, sandstone, siltstone, shale, and mudstones, are observed unconformably above the Midyat group. The Karadut complex, consisting of Cretaceous-aged siliceous shale, clayey limestone, limestone, and chert belonging to the allochthonous Kocial-Karadut nappes in the region, was settled in the region at the end of the Upper Cretaceous. All rock units are covered with Pliocene-Quaternary unnamed terrestrial sediments and Quaternary alluviums [51]. On a smaller scale, the local geology of the study area consists of Quaternary-aged Alluvium (Qal), residual (Kkad) units belonging to the Upper Cretaceous-aged Black Mulberry Complex, and units belonging to the Black Mulberry Complex (Kkad). Alluvium (Qal) units are in the form of gray, greenish-gray, light brown-cream colored, and reddish-brown colored, gravel, sand, silt, and clay, which are transitional with each other, and these units are low-medium-high-plasticity clay, well-poorly graded sand, it were observed in the form of clayey sand, gravelly sand, clayey gravel, silty gravel, sandy gravel, and occasionally blocks. The residual units belonging to the Black Mulberry Complex (Kkad) were observed as reddish-brown-colored low-plasticity clay, clayey sand, and clayey gravel. A general geological map of Golbasi and its surroundings is shown in Figure 4. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Station** & **TEC-2007** & **ZA (2018)** & **ZE (2018)** & **2018/2007 (ZA)** & **2018/2007 (ZE)** \\ \hline
208 Golbasi & 1 & 0.974 & 1.127 & 0.97 & 1.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison of spectral acceleration coefficients. Like the whole of Southeastern Anatolia, two main tectonic faults are observed in the area where Adyaman is located. The first of these tectonic phases is the compressional regime that took effect during the Upper Campanian-Lower Maestristian period and resulted in the settlement of allochthonous units in the Kastel basin and occurred due to the subduction of the Arabian plate under the Anatolian plate. This compression regime caused the Kodali and Karadut Complexes, which form allochthonous units in the northern areas, to drift southwards and settle on the platform with thrusts in the north, while in the southern parts (Kastel basin), they settled into the basin with gravity shifts. The compression that caused these events caused deformations (folding and fracture) in the southern parts of the platform, the effect of which gradually decreased towards the south.