# Seismic Vulnerability Assessment of Historical Masonry Buildings in Croatian Coastal Area
An estimation of the seismic vulnerability of a large number of buildings at an urban scale is much more demanding because it is not possible to carry out a nonlinear analysis for all of these buildings. One of the possible ways to solve this problem is the definition of fragility curves by means of a numerical analysis, coupled with statistical processing of the results. The fragility curves relate the probabilities of exceeding a specific damage measure for a certain intensity [5; 6; 7]. Several studies using fragility curves were recently performed to evaluate the seismic vulnerabilities and damage scenarios of urban centers to identify the main criticalities [8; 9; 10; 11; 12; 13; 14; 15; 16]. Empirical methods like the damage probability index method [17] and the vulnerability index method [18; 19] have also been widely employed to define the vulnerability of urban areas. Studies based on the damage probability index method [20; 21] use probabilistic matrices of damage for the prediction of the damage patterns corresponding to different seismic events. The main finding of the damage probability index method is that certain structural typologies share the same probability of damage for a given intensity of earthquake. Many studies have been developed using different macroseismic scales, such as the Medvedev-Sponheuer-Karnik (MSK) scale, the Mercalli-Cancani-Sieberg (MCS) scale, and the European macroseismic scale (EMS-98) [22]. Among these, the EMS-98 scale is the most commonly used [22], which identifies five categories of damage. These damage categories very roughly estimate damage to both structural and non-structural elements. Vulnerability assessments based on the vulnerability index method mostly use an improved version of the original Italian GNDT approach, developed by the Italian National Group for the Defense against Earthquakes [19]. It calibrates the weights of vulnerability parameters based on a large database of buildings damaged by past earthquakes [23; 24; 25]. To calculate the vulnerability of each building, this approach uses information about geometrical, structural, and material parameters and other relevant characteristics, such as structural typologies, horizontal and vertical irregularities, age, and conservation state. Another established approach to the estimation of earthquake-induced losses is HAZUS [26; 27], originally developed for the building typologies typical of regions in the USA. A significant contribution to the simulation of earthquake risk scenarios in Europe was achieved by the RISK-UE project [21; 28]. This project has developed a methodology for the evaluation of direct and indirect damages caused by different earthquake scenarios and the consequences of the damage. The method has been applied to seven European cities. Moreover, a building classification for typical European buildings has been proposed. According to this method, vulnerability and fragility curves are represented in two ways. The first way is through damage-seismic intensity curves, where the damage is defined in the interval 0-5, whereas the seismic intensity is determined using the EMS-98 macroseismic scale. The second way uses capacity curves, obtained through non-linear analyses of buildings typical of a certain class, for the purpose of deriving the fragility curves. The main difficulty in the application of this approach is how to assign an appropriate class to a particular building. Most of the aforementioned approaches require the calibration of vulnerability and fragility curves via post-earthquake damage observations. Some other studies have analytically evaluated these vulnerability functions [29]. If the methodology of the vulnerability index is used for the seismic vulnerability assessment, a relation between the vulnerability index, the earthquake intensity, and the damage of the building can be established, using the observation data regarding the damage to buildings induced by past earthquakes [18; 30].