This study provides the results of a study conducted to evaluate the seismic loss of residential ... more This study provides the results of a study conducted to evaluate the seismic loss of residential buildings in Karaj, Iran, caused by the rupture of North Tehran Fault (7.1 Mw). One of the main concerns of seismic risk assessment in Karaj is proper considering the near-source effects of the NTF fault, which passes through the city. In the present study, the finite-fault approach with dynamic corner frequency was first employed to simulate the acceleration time histories. This is an appropriate approach to take into account the source, path effects, directivity and site condition on seismic waves. The results of seismic hazard showed that the PGA values vary between 0.15 to 0.55g, with maximum values nearby the NTF fault. Afterwards, a high-quality database of residential buildings consists of 26 building types was compiled. A set of compatible vulnerability curves were also employed. The results indicated that the loss ratio, defined as the ratio of the loss to the total exposed econ...
This paper provides a review of the procedure of customizing ShakeMap V4.0 provided by U.S. Geolo... more This paper provides a review of the procedure of customizing ShakeMap V4.0 provided by U.S. Geological Survey based on seismic characteristics of Iran. Selecting appropriate GMPEs, adopting a suita...
In order to estimate the human loss after an earthquake to address risk mitigation and response m... more 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/s 2) 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.
In this study, a comprehensive loss model using the most recent census data (2016) together with ... more 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 socioeconomic conditions.
Bulletin of the Seismological Society of America, 2015
Determination of seismic sources is the first step in probabilistic seismichazard analysis (PSHA)... more Determination of seismic sources is the first step in probabilistic seismichazard analysis (PSHA); however, this step, especially in low seismic regions, is often controversial. In conventional PSHA procedure, determination of seismic sources is merely based on the subjective judgments of experts, and in many cases, there are great differences among proposed seismic models in a specific region. As a result, one important source of uncertainty in PSHA is due to determination of seismic sources. In this article, by combination of fuzzy clustering analysis and Monte Carlo simulation, an objective method for determination and probabilistic modeling of seismic sources is presented. By clustering spatial locations of earthquakes, it is possible to specify the extent of each seismic source in an objective way. A cluster quality index is used to identify the optimum number of clusters. The density and spread of events in each cluster determines the geometrical shape of seismic sources. Moreover, in this article a method is proposed to construct spatial probability density functions (PDFs) of earthquake locations based on the results of fuzzy clustering analysis. The spatial PDF of earthquakes can be used for the generation of synthetic events in Monte Carlo simulation. The Azarbaijan region, with its varied seismotectonics and generally high seismicity, is used as an important area of seismicity in which to develop and demonstrate the application and capability of fuzzy clustering analysis in specifying seismic sources. The PSHA is performed for the city of Tabriz, and a comprehensive comparison is made between the results of conventional PSHA, ordinary Monte Carlo hazard analysis, and the proposed method. The results indicate there is an objective relationship between observed seismicity and seismotectonic evidences in the region. Moreover, the distribution of synthetic events is highly correlated with the observed seismicity, seismotectonic, and geological information of the region. BSSA Early Edition / 1
Journal of Seismology and Earthquake Engineering, 2019
In this study, seismological aspects of the 2017 Sarpol-e Zahab earthquake has been investigated.... more In this study, seismological aspects of the 2017 Sarpol-e Zahab earthquake has been investigated. The Sarpol-e Zahab earthquake, of magnitude 7.3 (Mw), occurred in southwestern Iran on November 12, 2017. Here, we investigated the properties of the strong ground motions of the earthquake using the records provided by Iranian Strong Motion Network (ISMN). At Sarpol-e Zahab (SPZ) station, about 30 km south of the epicenter, the recorded peak ground acceleration (PGA) and peak ground velocity (PGV) in both horizontal and vertical components were remarkably large, and visual inspection of the velocity time history reveals a pulse-like shape. Besides, the response spectra of the recordings were determined and were compared to the 2800 seismic code spectrum. Furthermore, the earthquake engineering parameters for this earthquake were estimated and were compared with the values of other large destructive earthquakes in Iran. Finally, based on the recorded strong motion data and observed info...
This study provides the results of a study conducted to evaluate the seismic loss of residential ... more This study provides the results of a study conducted to evaluate the seismic loss of residential buildings in Karaj, Iran, caused by the rupture of North Tehran Fault (7.1 Mw). One of the main concerns of seismic risk assessment in Karaj is proper considering the near-source effects of the NTF fault, which passes through the city. In the present study, the finite-fault approach with dynamic corner frequency was first employed to simulate the acceleration time histories. This is an appropriate approach to take into account the source, path effects, directivity and site condition on seismic waves. The results of seismic hazard showed that the PGA values vary between 0.15 to 0.55g, with maximum values nearby the NTF fault. Afterwards, a high-quality database of residential buildings consists of 26 building types was compiled. A set of compatible vulnerability curves were also employed. The results indicated that the loss ratio, defined as the ratio of the loss to the total exposed econ...
This paper provides a review of the procedure of customizing ShakeMap V4.0 provided by U.S. Geolo... more This paper provides a review of the procedure of customizing ShakeMap V4.0 provided by U.S. Geological Survey based on seismic characteristics of Iran. Selecting appropriate GMPEs, adopting a suita...
In order to estimate the human loss after an earthquake to address risk mitigation and response m... more 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/s 2) 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.
In this study, a comprehensive loss model using the most recent census data (2016) together with ... more 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 socioeconomic conditions.
Bulletin of the Seismological Society of America, 2015
Determination of seismic sources is the first step in probabilistic seismichazard analysis (PSHA)... more Determination of seismic sources is the first step in probabilistic seismichazard analysis (PSHA); however, this step, especially in low seismic regions, is often controversial. In conventional PSHA procedure, determination of seismic sources is merely based on the subjective judgments of experts, and in many cases, there are great differences among proposed seismic models in a specific region. As a result, one important source of uncertainty in PSHA is due to determination of seismic sources. In this article, by combination of fuzzy clustering analysis and Monte Carlo simulation, an objective method for determination and probabilistic modeling of seismic sources is presented. By clustering spatial locations of earthquakes, it is possible to specify the extent of each seismic source in an objective way. A cluster quality index is used to identify the optimum number of clusters. The density and spread of events in each cluster determines the geometrical shape of seismic sources. Moreover, in this article a method is proposed to construct spatial probability density functions (PDFs) of earthquake locations based on the results of fuzzy clustering analysis. The spatial PDF of earthquakes can be used for the generation of synthetic events in Monte Carlo simulation. The Azarbaijan region, with its varied seismotectonics and generally high seismicity, is used as an important area of seismicity in which to develop and demonstrate the application and capability of fuzzy clustering analysis in specifying seismic sources. The PSHA is performed for the city of Tabriz, and a comprehensive comparison is made between the results of conventional PSHA, ordinary Monte Carlo hazard analysis, and the proposed method. The results indicate there is an objective relationship between observed seismicity and seismotectonic evidences in the region. Moreover, the distribution of synthetic events is highly correlated with the observed seismicity, seismotectonic, and geological information of the region. BSSA Early Edition / 1
Journal of Seismology and Earthquake Engineering, 2019
In this study, seismological aspects of the 2017 Sarpol-e Zahab earthquake has been investigated.... more In this study, seismological aspects of the 2017 Sarpol-e Zahab earthquake has been investigated. The Sarpol-e Zahab earthquake, of magnitude 7.3 (Mw), occurred in southwestern Iran on November 12, 2017. Here, we investigated the properties of the strong ground motions of the earthquake using the records provided by Iranian Strong Motion Network (ISMN). At Sarpol-e Zahab (SPZ) station, about 30 km south of the epicenter, the recorded peak ground acceleration (PGA) and peak ground velocity (PGV) in both horizontal and vertical components were remarkably large, and visual inspection of the velocity time history reveals a pulse-like shape. Besides, the response spectra of the recordings were determined and were compared to the 2800 seismic code spectrum. Furthermore, the earthquake engineering parameters for this earthquake were estimated and were compared with the values of other large destructive earthquakes in Iran. Finally, based on the recorded strong motion data and observed info...
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