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In order to estimate the human loss after an earthquake to address risk mitigation and response measures, appropriate models should be developed based on local conditions. In this paper, an empirical model for estimating the mortality rate based on shaking related parameter (PGA) is presented for Iran. For this purpose, a reliable fatality database of past earthquakes occurred in the country (between 1962 and 2017) along with corresponding ground motion shaking maps were compiled. It includes information of 88 fatal earthquakes in different cities and villages, compiled from reliable resources. Three distinct functional forms including log-linear, exponential and lognormal cumulative distribution were applied to be fitted to data. To evaluate the appropriateness of different functional forms a residual analysis was performed. The results indicate that the log-linear model shows the best performance. Additionally, a sensitivity analysis was performed to evaluate the impact of events with highest contributions in database on fatality function. The results depicted that excluding data of Bam (2003), Iran Earthquake may reduce fatality ratio to about 5%. This can be related to the paucity of data in high acceleration ranges (near 800 cm/s2) in the database. Finally, two separate curves have been developed for day and night. As expected, the result depicted that fatality ratio in day time is much lower than the night hours. The proposed model can be used for rapid loss assessment in Iran and other countries with similar construction types to provide an initial estimation of deaths after earthquakes or determining the priorities for risk reduction.

This paper presents the results of a study carried out to assess the probable seismic loss, in terms of damage to residential buildings, in the case of the west segment of the North Tehran Fault (NTF) seismic scenario in Karaj, Iran. Accordingly, it is crucial to first properly estimate the ground motion intensities. However, most of empirical ground motion prediction equations are poorly constrained at short ranges, and the data may only partially account for the rupture process. Hence, the stochastic finite-fault method with dynamic corner frequency was applied. This is an appropriate tool for addressing source, path, and near-source effects. It is noted that this method is dependent on many parameters which should be properly tuned. Thus, a set of sensitivity analyzes for the hypocenter locations and the quality factors were performed. The results from the simulations were used to develop a curve for estimating the ground motion values. Then, a high-quality building exposure model composed of 26 building classes based on the most recent census data was compiled. Finally, by applying appropriate fragility curves, damages to buildings from potential earthquakes were assessed. The outcomes showed that the mean damage ratio for the whole of the city is about 18.2% ± 5.3. In addition, a disaggregation analysis is done to identify the most vulnerable building types. The results showed that adobe and low-quality masonry buildings contribute the most to loss. The findings from this study can be used to provide risk reduction plans in Karaj.

A probabilistic seismic risk assessment is conducted in this study to quantify Annualized Earthquake Loss (AEL) of Tehran, the capital of Iran. To do so, a comprehensive review of three main components of risk assessment including the seismic hazard analysis, exposure model and vulnerability functions is performed. The classical seismic hazard analysis is carried out based on the most recent earthquake catalog by considering the available uncertainties. A high-quality building exposure model based on recent census data with geographic resolution of census blocks is also compiled. According to available information, buildings are classified into 19 groups by considering their construction material, quality and height. The results show that sum of AEL in Tehran is about 10,488 million USD, which is equivalent to 0.16% of exposed economic value. The spatial distribution of AEL indicated that value of AEL in the eastern districts is higher; however, the relative seismic risk in term of AELR in the southern districts of the city is much higher. In addition, a disaggregation analysis per building typology is performed to identify the contribution of different building taxonomies in AEL. The results show that the masonry and low-quality steel and concrete structures with poor designing specifications have the highest contribution in AEL. The finding from this study can be used by local authorities, government and insurance sector in order to develop effective risk mitigation plans and a robust insurance scheme for Tehran, Iran.

This paper presents the results of a study carried out to develop a multi-severity casualty approach for predicting the number of fatalities and two levels of injuries resulting from an earthquake. The two levels of injuries are severity 1, which do not require hospitalization, and severity 2, which do require hospitalization. The method provides a probability distribution of casualty, which can assist policymakers and disaster management authorities in developing emergency response plans. The proposed approach takes into account two main sources of uncertainty: variations in ground motion values (by generating thousands of shaking maps considering the spatial correlation of intra-event uncertainty) and uncertainty in casualty rates (by using the fuzzy set theorem and random sampling). As a case study, the proposed method was applied to the Mosha fault seismic scenario (7.4 Mw) in Tehran, Iran. The results indicated that 200,300 people may lose their lives in that seismic scenario. Additionally, the number of injuries with severity 1 and severity 2 are estimated to be about 420,600 and 232,980, respectively. These numbers exceed the healthcare capacity in Tehran. The estimated number of fatalities was then compared with the results of some existing empirical models in the literature. This comparison revealed that the empirical models underestimate the number of fatalities due to various reasons, such as a lack of strong earthquakes in urban areas to be included in empirical models. Thus, the proposed approach has several advantages for estimating casualties in urban fabrics.

In this study, a comprehensive loss model using the most recent census data (2016) together with the updated earthquake catalog (till 2018) is employed to estimate the direct expected annualized loss of residential buildings in Tehran, Iran. This is an important parameter to determine insurance premium or to identify relative risk in a region. For this purpose, a fully probabilistic seismic loss model based on the stochastic event-based approach is adopted. The assessment includes the development of a robust approach to quantify the seismic hazard by taking into account dynamic soil response, compiling a high quality exposure of residential building and considering the most appropriate vulnerability models for different building classes. The result shows that average annual loss of building stock is around $0.331 billion which is about 0.29% of total exposed economic value. Also, the relative risk map of the region is presented in term of the annualized earthquake loss ratio. It demonstrates that the seismic risk in the middle and southern part of the city are much higher. In addition, a disaggregation analysis regarding the building typologies is performed to identify the most vulnerable building classes. The result indicates that the masonry and low quality steel and concrete structures with poor designing specification are the most vulnerable building classes. Majority of the buildings in southern part of Tehran are of these types, where accommodating low-income residents. The finding from this study can be used by local authorities, government and insurance sector in order to develop effective risk mitigation plans and a robust insurance scheme for Tehran, Iran. In addition, the presented approach can be applied in other cities with different socio-economic conditions.

Providing appropriate near real time ground motion shaking map is a critical requirement to effectively manage the consequence of an earthquake. In the present study, the standard procedure adopted by USGS ShakeMap to develop the ground motion shaking map is calibrated to implement in Iran. Selecting appropriate ground motion predictions equation and properly modeling of the local site condition are two important parameters that should be properly modeled to provide an appropriate ground motion shaking map. Here, a set of local, regional and global GMPEs that show good performance in the previous studies are adopted. Besides, the approach developed by Borcherdt [1] is used to take into account the local site condition. The VS30 of the region exploited from the proxy approach proposed by Wald and Allen [2]. The study evaluates the potential applicability of this method by compiling a database of measured and estimated VS30. The results indicate that the method outperforms than random selection of the site class. The calibrated model implements to generate the ground motion shaking map of the Sarpol-e Zahab, Iran earthquake (2017). The result shows that the approach performs better than employing GMPEs alone. The calibrated model can be used to generate the database of ground motion shaking of past earthquakes in Iran, which is an important requirement to develop empirical fragility or vulnerability models.