_Applied_  
_sciences_  
_Article_  
**The Effect of Site-Specific Design Spectrum on Earthquake-Building Parameters: A Case Study**  
**from the Marmara Region (NW Turkey)**  
**[PERSON] 1,*\({}^{\circled{\textcircled{\textcircled{\textcircled{\textcircled{\textcircled{\textcircled{\textcircled{\textcircled{\text{\textcircledcled{\text{\  
The first regulation about disasters based on edict was issued by [PERSON] after the earthquake that caused approximately 13.000 deaths in Istanbul on 14.09.1509 [7]. However, the first regulation was prepared after the 26 December 1939 earthquake that occurred in Erzincan and caused significant destruction [8]. It was first published in the 1940 as \"Italian Building Instruction for Construction in Earthquake Region\" [9]. In parallel with the development of technology, to minimize the earthquake-led losses, the rules of construction to be followed in building construction have been tried to be created, and these rules have been imposed as standards and regulations. This code has been continuously updated, taking into account the developments in engineering technologies and significant losses in earthquakes. Ten seismic design codes came into force in 1940, 1944, 1949, 1953, 1962, 1968, 1975, 1998, 2007, and 2018. The first four regulations contain only the rules about earthquakes. The 1962-1998 regulations include rules on all types of disasters such as flood, fire, and earthquake. The need for renewal of the code in 1998 emerged, after the major losses in 1999 Golcuk (Mw = 7.4) and Duzce (Mw = 7.2) earthquakes. Only earthquake-related rules were included with the code in 2007 for the first time [10]. Lastly, the loss of life and property in the 2011 Van earthquakes (Mw = 7.2 and Mw = 5.6) revealed the need to update the latest regulation. The latest seismic code was updated in 2018 and has been put into force since January 2019. It is called the Turkey Building Earthquake Code (TBEC-2018). The seismic hazard must be known correctly to determine the earthquake behavior of engineering structures and to reduce earthquake damage. In Turkey, seismic hazard maps have been produced so far due to the devastating earthquakes that caused significant life and property losses. These maps clearly provide significant data for engineers to obtain the possible risk level and determine the reliable design of structures affected by earthquakes. Turkey's first seismic hazard map was produced in 1945 and has been updated many times to date [11]. The previous earthquake hazard map was prepared based on the 475-year Peak Ground Acceleration (PGA) values and suggested acceleration ranges by [PERSON] et al. 1993 [12]. The earthquake hazard was divided into five different seismic zones in this map, graduated from 1 to 5. The same effective ground acceleration coefficient was proposed for each zone. Effective ground acceleration coefficient takes values of 0.4, 0.3, 0.2, and 0.1 for 1 st, 2 nd, 3 rd, and 4 th degree seismic zones, respectively [13]. This map came into force in 1996 and is known as the Turkey Earthquake Zone Map. All calculations related to the earthquake were performed on a regional basis in the previous code. The map using the probability method, which has an important place in terms of being the first prepared map, was used until 2019. However, with the development of methods related to seismic hazard calculations, the way of handling the uncertainties in ground motion, and seismic source modeling, it has become inevitable to update this map [11; 14; 15]. With this obligation, different working groups have been established within the scope of the research programs carried out by the Disaster and Emergency Management Presidency. Seismic sources, earthquake catalogs, earthquake recurrence models, ground motion prediction equations, model uncertainties, and seismic hazard calculations were examined separately, and parametric information required in earthquake hazard assessments was obtained.