A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms o...A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid recovery.The framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake recovery.In this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage mechanisms.Accordingly,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit states.In the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair events.The recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss estimation.As such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely circumvented.The proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype building.The results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the RCF.Particularly,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.展开更多
This paper proposes a risk analysis framework for substation structures based on reliability methods.Even though several risk assessment approaches have been developed for buildings,detailed risk analysis procedures f...This paper proposes a risk analysis framework for substation structures based on reliability methods.Even though several risk assessment approaches have been developed for buildings,detailed risk analysis procedures for infrastructure components have been lacking in prior studies.The proposed framework is showcased by its application to a system of interconnected structures at a power substation in Tehran.Finite element models of structures are developed and validated in accordance with previous experiments.The uncertainties in the material,mass,and geometric properties of structures are described by random variables that are input to the finite element model.An artificial ground motion model is employed to comprehensively consider uncertainty in ground motion.Monte Carlo sampling is subsequently conducted on the library of probabilistic models.The analysis resulted in the loss distribution in the life cycle of structures.Additionally,the loss associated with six earthquake scenarios having specific magnitudes and return periods is computed.The application provides insight into the most vulnerable equipment in the considered system.Furthermore,introduced risk measures can guide stakeholders to make risk-based decisions to optimize design or prioritize a retrofit of infrastructure components under conditions of uncertainty.展开更多
Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for pot...Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for potential large earthquakes. The authors map the probable asperities from the abnormally low b-value distribution, develop and employ a method for identifying current faulting behaviors of individual fault segment from the combinations of multiple seismicity parameter values, and make an effort to estimate the average recurrence intervals of character-istic earthquakes by using the parameters of magnitude-frequency relationship of the asperity segment. The result suggests that the studied fault zone contains 5 segments of different current faulting behaviors. Among them, the Mianning-Xichang segment of the Anninghe fault has been locked under high stress, its central part is probably an asperity with a relatively large scale. The Xichang-Puge segment of the Zemuhe fault displays very low seismicity under low stress. Both the locked segment and the low-seismicity segment can be outlined on the across-profile of relocated hypocenter depths. The Mianning-Xichang segment is identified to be the one with potential large earth-quake risk, for which the average recurrence interval between the latest M = 6.7 earthquake in 1952 and the next characteristic event is estimated to be 55 to 67 years, and the magnitude of the potential earthquake between 7.0 and 7.5. Also, it has been preliminarily suggested that for a certain fault segment, its faulting behaviors may change and evolve with time gradually.展开更多
Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for pot...Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for potential large earthquakes. The authors map the probable asperities from the abnormally low b-value distribution, develop and employ a method for identifying current faulting behaviors of individual fault segment from the combinations of multiple seismicity parameter values, and make an effort to estimate the average recurrence intervals of character-istic earthquakes by using the parameters of magnitude-frequency relationship of the asperity segment. The result suggests that the studied fault zone contains 5 segments of different current faulting behaviors. Among them, the Mianning-Xichang segment of the Anninghe fault has been locked under high stress, its central part is probably an asperity with a relatively large scale. The Xichang-Puge segment of the Zemuhe fault displays very low seismicity under low stress. Both the locked segment and the low-seismicity segment can be outlined on the across-profile of relocated hypocenter depths. The Mianning-Xichang segment is identified to be the one with potential large earth-quake risk, for which the average recurrence interval between the latest M = 6.7 earthquake in 1952 and the next characteristic event is estimated to be 55 to 67 years, and the magnitude of the potential earthquake between 7.0 and 7.5. Also, it has been preliminarily suggested that for a certain fault segment, its faulting behaviors may change and evolve with time gradually.展开更多
Following the 2008 Wenchuan M8 earthquake,the seismic risk of the northeastern section of the Longmenshan fault zone and the adjacent Hanzhong basin has become an issue that receives much concern.It is facing,however,...Following the 2008 Wenchuan M8 earthquake,the seismic risk of the northeastern section of the Longmenshan fault zone and the adjacent Hanzhong basin has become an issue that receives much concern.It is facing,however,the problem of a lack of sufficient data because of little previous work in these regions.The northeastern section of the Longmenshan fault zone includes three major faults：the Qingchuan fault,Chaba-Lin＇ansi fault,and Liangshan south margin fault,with the Hanzhong basin at the northern end.This paper presents investigations of the geometry,motion nature,and activity ages of these three faults,and reveals that they are strike slip with normal faulting,with latest activity in the Late Pleistocene.It implies that this section of the Longmenshan fault zone has been in an extensional setting,probably associated with the influence of the Hanzhong basin.Through analysis of the tectonic relationship between the Longmenshan fault zone and the Hanzhong basin,this work verifies that the Qingchuan fault played an important role in the evolution of the Hanzhong basin,and further studies the evolution model of this basin.Finally,with consideration of the tectonic setting of the Longmenshan fault zone and the Hanzhong basin as well as seismicity of surrounding areas,this work suggests that this region has no tectonic conditions for great earthquakes and only potential strong events in the future.展开更多
Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, ...Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, structural analysis, and optimization). SRE for planning mountain tunnels bridges the gap between the planning on the macro level and the design/analysis on the micro level regarding the risk management of infrastructural systems. A transition from subjective or qualitative description to objective or quantitative quantification of seismic risk is aimed to improve the seismic behavior of the mountain tunnel and thus reduce the associated seismic risk. A new method of systematic SRE for the planning mountain tunnel was presented herein. The method employs extension theory(ET)and an ET-based improved analytical hierarchy process. Additionally, a new risk-classification criterion is proposed to classify and quantify the seismic risk for a planning mountain tunnel. This SRE method is applied to a mountain tunnel in southwest China, using the extension model based on matter element theory and dependent function operation.The reasonability and flexibility of the SRE method for application to the mountain tunnel are illustrated.According to different seismic risk levels and classification criteria, methods and measures for improving the seismic design are proposed, which can reduce the seismic risk and provide a frame of reference for elaborate seismic design.展开更多
Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized ...Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized in five seismic provinces as potential hazard sources. Maximum magnitude potential for each of these sources is calculated. Peak ground acceleration (PGA) values at the seven coastal cities due to the maximum credible earthquake on the relevant source are also obtained. Cities of Gwadar and Ormara with acceleration values of 0.21g and 0.25g respectively fall in the high seismic risk area. Cities of Turbat and Karachi lie in low seismic risk area with acceleration values of less than 0.1g. The Probabilistic PGA maps with contour interval of 0.05g for 50 and 100 years return period with 90% probability of non-exceedance are also compiled.展开更多
The seismotectonic method is used to study the seismogenic structures and the maximum potential earthquake around an engineering site in order to determine the seismic risk at the site. Analysis of seismic risk from s...The seismotectonic method is used to study the seismogenic structures and the maximum potential earthquake around an engineering site in order to determine the seismic risk at the site. Analysis of seismic risk from site effect seismic intensity data, in combination with regional seismo_geological data, using the seismotectonic method can provide a more reliable result. In this paper, taking the area of six reservoir dam sites in western Anhui as an example, we analyze the seismic risk from site effect seismic intensity data in combination with the seismotectonic conditions and find that P (I≥i)=10% over 50 years. The result shows that the seismogenic structure and the maximum potential earthquake have a controlling effect on seismic risk from future earthquakes in the area around the site.展开更多
In this paper, from the differences to evaluate and manage the seismic uncertainty we analyzed the imperfection of determinant method and the Poisson model of probabilistic method in seismic risk analysis. Through stu...In this paper, from the differences to evaluate and manage the seismic uncertainty we analyzed the imperfection of determinant method and the Poisson model of probabilistic method in seismic risk analysis. Through studying and summarizing the relation of earthquake occurrence time, intensity and place, we deemed that the time uncertainty of earthquake occurrence interacts with that of space. We expressed the interaction with the concept of upbound earthquake occurrence number and deduced the Binomial model. The Binomial model can be applied in reflecting uncertainty of time and space. Comparing the determinant method and the Poisson model of probabilistic method with the Binomial model, we have got the idea that determinant and the Poisson model are two limits of the Binomial model. When the temporal-spatial uncertainty is infinity or infinitesimal, the binomial model tends to a determinant method and a Poisson model respectively. We also gave an approach to show the implied probability of intensity in the Earthquake intensity Zoning Map in China made in 1977. We also estimated the maximums of the implied probability of five high intensity areas in the Northern China.展开更多
The greater part of urban heritage, especially of the medium and small Algerian cities, is subject to a major seismic risk. The probability of a happening earthquake is strong, and the territories vulnerability is gre...The greater part of urban heritage, especially of the medium and small Algerian cities, is subject to a major seismic risk. The probability of a happening earthquake is strong, and the territories vulnerability is great. Legislative procedures are implemented to support urban heritage and managing natural disasters. In fact, the PPSMVSS （permanent plan of safeguard and enhancement of saved sectors） as an instrument of protection, preservation and enhancement of this heritage, in its content, does not guide decision makers on how to manage the vulnerability of preserved areas from the earthquake. After the disaster of the earthquake that hit the Algerian Centre （wilaya of Boumerdes） in 2003. A legislative framework was created while other texts have been adapted. Emergency measures operations are launched to preserve the under threat monuments and protected areas. Saved sectors of Dellys, in the wilaya of Boumerdes and T6n^s in the wilaya of Chlef, are all the time subjected to seismic risk. This article presents a comparative study of two PPSMVSS, Dellys and T6n6s, and the management of the vulnerability of their two safeguarded areas. As a result of this study, some indicators were identified to allow the development of plans for the protection and management natural risks of these protected areas.展开更多
Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,th...Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,the activity and tectonic features of the faults are determined synthetically.Using seismo-geological data,and the historical and modern seismicity data,the frequency-magnitude relationship model normalized by 500a is established and based on the relationship between the upper limit of maximum magnitude M u and a t/b,the maximum magnitudes of the sea section of the Haihe river fault and the Haiyi fault are calculated.Then Poisson probability model is adopted and the quantitative parameters,such as the maximum magnitude,occurrence probability,recurrence cycle of the faults in the south Tianjin offshore areas in the coming 50～200a,are calculated.展开更多
This study presents a probabilistic seismic risk model for the Beijing-Tianjin-Hebei region in China.The model comprises a township-level residential building exposure model,a vulnerability model derived from the Chin...This study presents a probabilistic seismic risk model for the Beijing-Tianjin-Hebei region in China.The model comprises a township-level residential building exposure model,a vulnerability model derived from the Chinese building taxonomy,and a regional probabilistic seismic hazard model.The three components are integrated by a stochastic event-based method of the OpenQuake engine to assess the regional seismic risk in terms of average annual loss and exceedance probability curve at the city,province,and regional levels.The novelty and uniqueness of this study are that a probabilistic seismic risk model for the Beijing-Tianjin-Hebei region in China is developed by considering the impact of site conditions and epistemic uncertainty from the seismic hazard model.展开更多
After a brief introduction of the framework of seismic risk assessment (SRA), the current state of SRA in China is presented in five parts: the vulnerability assessment of structures, SRA methodology, earthquake loss ...After a brief introduction of the framework of seismic risk assessment (SRA), the current state of SRA in China is presented in five parts: the vulnerability assessment of structures, SRA methodology, earthquake loss estimation, disaster management and laws, and geographical information system (GIS), with emphasis on current Chinese practice. The vulnerability matrices used are mostly from recent earthquake experiences in China, such as the 1985 Haicheng Earthquake and the 1986 Tangshen Earthquake, especially for structures such as the adobe and unreinforced masonry buildings. For SRA, different requirements are required for different scales of exposures, e.g., global scale, regional scale, city scale, and individual scale. Simple and average conditions are used for exposure estimation and seismic hazard assessment (SHA) for the global scale, and very specific and detailed conditions for the individual scale, such as for a specific engineering project. In China, there are some standardized requirements for SHA and SRA in addition to seismic design codes, which are followed.展开更多
The seismicity of the Arabian plate, which is the aim of this paper, is controlled by the ZagrosTaurus collision zone in the North, the Indian expansion zone and the Arab golf in the South and the East, the Dead Sea F...The seismicity of the Arabian plate, which is the aim of this paper, is controlled by the ZagrosTaurus collision zone in the North, the Indian expansion zone and the Arab golf in the South and the East, the Dead Sea Fault, the North continuity of the Red Sea, and the Syrian rift, which links the rigid Arabian plate to the mobile ophiolite belt of Cyprus-Southern Turkey in the West. These major elements with their related fracture system, make the Arabian plate an important seismic centre. To attain our purpose, a variable methodology is used in: measurements of movement rate-displacement in the field, the analysis of historical and recent seismic data, and physical effects on the structures. The movement rate-displacement, calculated in the field by different specialists, varies from 2 to 6 mm/year. This rate increases from 2 - 3 mm/year in the North, to 6 mm in the South. These estimations are confirmed by historical seismic data, the recent seismic recorded by the Arab seismic centers, and physical effects on the building structures in the region. The analysis of historical and recent seismic data recorded in the seismic centre show that the seismicity in this plate, tend to fade out with time. This result is in agreement with recent estimations on the movement rate, and in line with the decrease of major seismic intensity, which has occurred during the last millennium. A conclusion of time-evolution seismicity is traced, and a seismic zoning map, for the Arabian plate, using movement rate, seismic data, and tectono-geodynamic analysis, is proposed.展开更多
The paper discusses how to approach the problem of the social mitigation of seismic risk, in order to reduce damage and grief consequent to earthquakes. An alert protocol, intended as a working hypothesis, is proposed...The paper discusses how to approach the problem of the social mitigation of seismic risk, in order to reduce damage and grief consequent to earthquakes. An alert protocol, intended as a working hypothesis, is proposed based on the experience gained from analysis of the behaviour and social response to the threat before and after the great disaster of the L’Aquila earthquake on 6th April 2009. Authors propose a protocol addressing four levels of increasing alert based on signs of earthquake preparation and social concerns. In this sense, it works as an intensity scale and does not strictly relate to earthquake size (magnitude) or seismic hazard. The proposed alert protocol provides sensible measures for reducing vulnerability, which is the only factor that can be more or less efficiently controlled, based on structural and behavioural adjustments. Factors indicating the difficult relationship between politicians, scientific community and citizens are considered: 1) a serious gap between researchers and citizens;2) measures adopted by local administrators and the National Civil Protection Service not agreed by the population;3) misunderstanding originated from a lack of clarity of communication about scientific terminology;and 4) the lack of an alert procedure protocol. In the current situation, all these problems are crucial and contribute to the unpreparedness to face a seismic event, and thus greatly increase the risk. The adoption and implementation of an alert procedure protocol requires a preliminary assessment of the context and should be adapted to the local sensibility and culture. The application of a protocol may reduce the contrasts between preventive measures and individual responsibilities, making mitigation measures more feasible and socially acceptable. In this paper, risk evaluation is not strictly related to probabilistic or deterministic predictions. In fact, this is a result of a project that comes from the general analysis of risk and is not intended to give an alternative hazard estimate method. This paper proposes an alert protocol addressing four levels of increasing alert based on signs of earthquake generating preparation and social concerns. Finally, there is a suggestion on how to gradually communicate the threat and get citizens involved in the risk mitigation process.展开更多
During the preparation process of a great earthquake, there are certain patterns of less randomness but more order in the space-time distribution of micro-earthquakes, which had been proved by seismic events and exper...During the preparation process of a great earthquake, there are certain patterns of less randomness but more order in the space-time distribution of micro-earthquakes, which had been proved by seismic events and experiments. The information entropy concerning the dimension of the order in seismic distribution is systematically defined from the point of modern statistical physics in this paper. Relations of dynamic variations of information entropy with a strong shock occurrence time and the distribution of information with a strong shock occurrence place were approached through seismic data from the Wuqia, Xikar, Wushi, and Manasi regions in Xinjiang. It is indicated that before strong earthquakes, the value of information entropy often noticeably drops in seismic region, and generally much lower in the epicentral area than the surrounding regions. These two characters are of important significance in strong shock risk region determination and large shock tendency prediction.展开更多
Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity...Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity method would be used to obtain β,λ,and Imax,and also achieve the results of risk analysis on each site.At the same time,the "logic tree" method can be used to calibrate the uncertainty of the risk on each site.Then the final results of risk analysis indicate that this method is feasible,particularly for the sites showing intensity anomaly.展开更多
The article has been retracted due to the investigation of complaints received against it. The paper is withdrawn due to paper duplication which has been published by the author years before. This paper published in V...The article has been retracted due to the investigation of complaints received against it. The paper is withdrawn due to paper duplication which has been published by the author years before. This paper published in Vol.1 No.1 1-12 (pages), 2012, has been removed from this site.展开更多
A complete research of seismic risk assessment is presented herein focused on the existing build- ings of the extended urban region of Athens in Greece. The seismic risk assessment is fulfilled by discriminating the c...A complete research of seismic risk assessment is presented herein focused on the existing build- ings of the extended urban region of Athens in Greece. The seismic risk assessment is fulfilled by discriminating the current study in two approaches, probable and actual, conducting afterwards between them a comparison analysis. In the first part, a pilot methodology is developed for the seismic loss assessment in monetary terms regarding the buildings damages, consistent with the National Programme for Earthquake Management of Existing Buildings (NPEMEB). The building stock consists of typical building types of Southern Europe and refers to 750,085 buildings (18.80% of buildings in Greece) situated in the entire region of Athens according to the results of the 2000-1 statistical census. A wider research of seismic risk assessment could include direct losses of infrastructures and indirect economic losses. The evaluation of loss due to building damage in a certain region requires an assessment of both seismic hazard and vulnerability of the building stock in the study area. Four different existing damage scenarios are applied for the vulnerability assessment. The results of the seismic risk assessment for the four different aspects of the es- timated damage and the different soil conditions are presented in a map of the study region. The existing vulnerability curves corresponding to defined types of buildings have been derived from the National Technical Chamber of Greece and also from recently developed DPMs. The last DPMs were obtained in a previous research (Eleftheriadou, 2009) from the process of a created damage database after the 7th of September 1999 Parnitha’s earthquake and comprised 180,945 buildings which developed damage of varying degree, type and extent. In the second part of the research, the seismic risk is evaluated from the available data regarding the mean statistical repair/ strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the same (1999 Parnitha’s) seismic event. Data regarding the compatible (budget approved according to the ministry’s provisions) repair cost has been collected. The structural losses in monetary terms for the 180,427 buildings damaged structures are evaluated equal to 2450.0 Μ€, 1887.8 Μ€ and 2118.9 Μ€ based on the previously mentioned statistical seismic risk data. The statistically derived repair cost for Attica is compared with the results of the economic loss esti- mation for buildings using the aforementioned risk assessment methodology. From the analysis results, the seismic scenario based on the recently developed DPMs (Eleftheriadou, 2009) pre- sented the better correlation (2627.77 M€) with the total statistically evaluated repair cost (2450.02 M€). It is important to stress that the inclusion of the coefficient parameter S overes- timates significantly the seismic losses. The last result should be taken into consideration in future risk researches. The comparison of the estimated economic loss with the statistical repair cost calibrates the reliability of the commonly used risk assessment method and serves in the im- provement of seismic security prioritizing the criteria for seismic rehabilitation programmes of existing buildings.展开更多
The seismic risk analysis method and some special aspects concerning its application to ocean oil platforms are reviewed briefly through an example of analysis for the oil platforms in the Bohai sea. In view of the fe...The seismic risk analysis method and some special aspects concerning its application to ocean oil platforms are reviewed briefly through an example of analysis for the oil platforms in the Bohai sea. In view of the features of temporal and spatial distribution of earthquakes in China, it is emphasized that the temporal and spatial inhomogeneity of seismicity should be thoroughly studied when dealing with a specific project where a short service life and a high degree of safety are required.展开更多
基金National Key Research and Development Program of China under Grant No.2022YFC3803004Postgraduate Research&Practice Innovation Program of Jiangsu Province under Grant No.SJCX20_0031Fundamental Research Funds for the Central Universities under Grant No.3205002108D。
文摘A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid recovery.The framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake recovery.In this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage mechanisms.Accordingly,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit states.In the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair events.The recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss estimation.As such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely circumvented.The proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype building.The results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the RCF.Particularly,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.
文摘This paper proposes a risk analysis framework for substation structures based on reliability methods.Even though several risk assessment approaches have been developed for buildings,detailed risk analysis procedures for infrastructure components have been lacking in prior studies.The proposed framework is showcased by its application to a system of interconnected structures at a power substation in Tehran.Finite element models of structures are developed and validated in accordance with previous experiments.The uncertainties in the material,mass,and geometric properties of structures are described by random variables that are input to the finite element model.An artificial ground motion model is employed to comprehensively consider uncertainty in ground motion.Monte Carlo sampling is subsequently conducted on the library of probabilistic models.The analysis resulted in the loss distribution in the life cycle of structures.Additionally,the loss associated with six earthquake scenarios having specific magnitudes and return periods is computed.The application provides insight into the most vulnerable equipment in the considered system.Furthermore,introduced risk measures can guide stakeholders to make risk-based decisions to optimize design or prioritize a retrofit of infrastructure components under conditions of uncertainty.
基金Chinese Joint Seismological Science Foundation (102002).
文摘Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for potential large earthquakes. The authors map the probable asperities from the abnormally low b-value distribution, develop and employ a method for identifying current faulting behaviors of individual fault segment from the combinations of multiple seismicity parameter values, and make an effort to estimate the average recurrence intervals of character-istic earthquakes by using the parameters of magnitude-frequency relationship of the asperity segment. The result suggests that the studied fault zone contains 5 segments of different current faulting behaviors. Among them, the Mianning-Xichang segment of the Anninghe fault has been locked under high stress, its central part is probably an asperity with a relatively large scale. The Xichang-Puge segment of the Zemuhe fault displays very low seismicity under low stress. Both the locked segment and the low-seismicity segment can be outlined on the across-profile of relocated hypocenter depths. The Mianning-Xichang segment is identified to be the one with potential large earth-quake risk, for which the average recurrence interval between the latest M = 6.7 earthquake in 1952 and the next characteristic event is estimated to be 55 to 67 years, and the magnitude of the potential earthquake between 7.0 and 7.5. Also, it has been preliminarily suggested that for a certain fault segment, its faulting behaviors may change and evolve with time gradually.
基金Chinese Joint Seismological Science Foundation (102002).
文摘Using the data of regional seismic network, this paper analyzes the current faulting behaviors of different segments of the Anninghe-Zemuhe fault zone, western Sichuan, and identifies the likely risky segments for potential large earthquakes. The authors map the probable asperities from the abnormally low b-value distribution, develop and employ a method for identifying current faulting behaviors of individual fault segment from the combinations of multiple seismicity parameter values, and make an effort to estimate the average recurrence intervals of character-istic earthquakes by using the parameters of magnitude-frequency relationship of the asperity segment. The result suggests that the studied fault zone contains 5 segments of different current faulting behaviors. Among them, the Mianning-Xichang segment of the Anninghe fault has been locked under high stress, its central part is probably an asperity with a relatively large scale. The Xichang-Puge segment of the Zemuhe fault displays very low seismicity under low stress. Both the locked segment and the low-seismicity segment can be outlined on the across-profile of relocated hypocenter depths. The Mianning-Xichang segment is identified to be the one with potential large earth-quake risk, for which the average recurrence interval between the latest M = 6.7 earthquake in 1952 and the next characteristic event is estimated to be 55 to 67 years, and the magnitude of the potential earthquake between 7.0 and 7.5. Also, it has been preliminarily suggested that for a certain fault segment, its faulting behaviors may change and evolve with time gradually.
基金supported by the Key Projects in the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (Grant No. 2012BAK15B01-03)the National Science & Technology Major Project (Grant No. 2011ZX06002-010-15)
文摘Following the 2008 Wenchuan M8 earthquake,the seismic risk of the northeastern section of the Longmenshan fault zone and the adjacent Hanzhong basin has become an issue that receives much concern.It is facing,however,the problem of a lack of sufficient data because of little previous work in these regions.The northeastern section of the Longmenshan fault zone includes three major faults：the Qingchuan fault,Chaba-Lin＇ansi fault,and Liangshan south margin fault,with the Hanzhong basin at the northern end.This paper presents investigations of the geometry,motion nature,and activity ages of these three faults,and reveals that they are strike slip with normal faulting,with latest activity in the Late Pleistocene.It implies that this section of the Longmenshan fault zone has been in an extensional setting,probably associated with the influence of the Hanzhong basin.Through analysis of the tectonic relationship between the Longmenshan fault zone and the Hanzhong basin,this work verifies that the Qingchuan fault played an important role in the evolution of the Hanzhong basin,and further studies the evolution model of this basin.Finally,with consideration of the tectonic setting of the Longmenshan fault zone and the Hanzhong basin as well as seismicity of surrounding areas,this work suggests that this region has no tectonic conditions for great earthquakes and only potential strong events in the future.
基金financially supported by the National Key Research and Development Program of China (2016YFB1200401)the Western Construction Project of the Ministry of Transport (Grant No. 2015318J29040)
文摘Seismic risk evaluation(SRE) in early stages(e.g., project planning and preliminary design)for a mountain tunnel located in seismic areas has the same importance as that in final stages(e.g.,performance-based design, structural analysis, and optimization). SRE for planning mountain tunnels bridges the gap between the planning on the macro level and the design/analysis on the micro level regarding the risk management of infrastructural systems. A transition from subjective or qualitative description to objective or quantitative quantification of seismic risk is aimed to improve the seismic behavior of the mountain tunnel and thus reduce the associated seismic risk. A new method of systematic SRE for the planning mountain tunnel was presented herein. The method employs extension theory(ET)and an ET-based improved analytical hierarchy process. Additionally, a new risk-classification criterion is proposed to classify and quantify the seismic risk for a planning mountain tunnel. This SRE method is applied to a mountain tunnel in southwest China, using the extension model based on matter element theory and dependent function operation.The reasonability and flexibility of the SRE method for application to the mountain tunnel are illustrated.According to different seismic risk levels and classification criteria, methods and measures for improving the seismic design are proposed, which can reduce the seismic risk and provide a frame of reference for elaborate seismic design.
文摘Estimation of seismic hazard for the fast developing coastal area of Pakistan is carried out using deterministic and probabilistic approaches. On the basis of seismotectonics and geology, eleven faults are recognized in five seismic provinces as potential hazard sources. Maximum magnitude potential for each of these sources is calculated. Peak ground acceleration (PGA) values at the seven coastal cities due to the maximum credible earthquake on the relevant source are also obtained. Cities of Gwadar and Ormara with acceleration values of 0.21g and 0.25g respectively fall in the high seismic risk area. Cities of Turbat and Karachi lie in low seismic risk area with acceleration values of less than 0.1g. The Probabilistic PGA maps with contour interval of 0.05g for 50 and 100 years return period with 90% probability of non-exceedance are also compiled.
文摘The seismotectonic method is used to study the seismogenic structures and the maximum potential earthquake around an engineering site in order to determine the seismic risk at the site. Analysis of seismic risk from site effect seismic intensity data, in combination with regional seismo_geological data, using the seismotectonic method can provide a more reliable result. In this paper, taking the area of six reservoir dam sites in western Anhui as an example, we analyze the seismic risk from site effect seismic intensity data in combination with the seismotectonic conditions and find that P (I≥i)=10% over 50 years. The result shows that the seismogenic structure and the maximum potential earthquake have a controlling effect on seismic risk from future earthquakes in the area around the site.
文摘In this paper, from the differences to evaluate and manage the seismic uncertainty we analyzed the imperfection of determinant method and the Poisson model of probabilistic method in seismic risk analysis. Through studying and summarizing the relation of earthquake occurrence time, intensity and place, we deemed that the time uncertainty of earthquake occurrence interacts with that of space. We expressed the interaction with the concept of upbound earthquake occurrence number and deduced the Binomial model. The Binomial model can be applied in reflecting uncertainty of time and space. Comparing the determinant method and the Poisson model of probabilistic method with the Binomial model, we have got the idea that determinant and the Poisson model are two limits of the Binomial model. When the temporal-spatial uncertainty is infinity or infinitesimal, the binomial model tends to a determinant method and a Poisson model respectively. We also gave an approach to show the implied probability of intensity in the Earthquake intensity Zoning Map in China made in 1977. We also estimated the maximums of the implied probability of five high intensity areas in the Northern China.
文摘The greater part of urban heritage, especially of the medium and small Algerian cities, is subject to a major seismic risk. The probability of a happening earthquake is strong, and the territories vulnerability is great. Legislative procedures are implemented to support urban heritage and managing natural disasters. In fact, the PPSMVSS （permanent plan of safeguard and enhancement of saved sectors） as an instrument of protection, preservation and enhancement of this heritage, in its content, does not guide decision makers on how to manage the vulnerability of preserved areas from the earthquake. After the disaster of the earthquake that hit the Algerian Centre （wilaya of Boumerdes） in 2003. A legislative framework was created while other texts have been adapted. Emergency measures operations are launched to preserve the under threat monuments and protected areas. Saved sectors of Dellys, in the wilaya of Boumerdes and T6n^s in the wilaya of Chlef, are all the time subjected to seismic risk. This article presents a comparative study of two PPSMVSS, Dellys and T6n6s, and the management of the vulnerability of their two safeguarded areas. As a result of this study, some indicators were identified to allow the development of plans for the protection and management natural risks of these protected areas.
基金funded by earthquake security infrastructure of Tianjin 11th "Five-year Plan" (Tianjin Development and Reforming Office[2009]-1230),the Spark Program of Earthquake Sciences(Grant No.XH13002)
文摘Based on faults surveying and research data in the Tianjin offshore areas,through studying tectonic structure,Quaternary activity,deep structure,stress and strain fields and seismicity in the Tianjin offshore areas,the activity and tectonic features of the faults are determined synthetically.Using seismo-geological data,and the historical and modern seismicity data,the frequency-magnitude relationship model normalized by 500a is established and based on the relationship between the upper limit of maximum magnitude M u and a t/b,the maximum magnitudes of the sea section of the Haihe river fault and the Haiyi fault are calculated.Then Poisson probability model is adopted and the quantitative parameters,such as the maximum magnitude,occurrence probability,recurrence cycle of the faults in the south Tianjin offshore areas in the coming 50～200a,are calculated.
基金The financial support received from the Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration(Grant No.2023B09)National Key R&D Program of China(2022YFC3004404)Shenzhen Science and Technology Program(ZDSYS20210929115800001)are gratefully acknowledged。
文摘This study presents a probabilistic seismic risk model for the Beijing-Tianjin-Hebei region in China.The model comprises a township-level residential building exposure model,a vulnerability model derived from the Chinese building taxonomy,and a regional probabilistic seismic hazard model.The three components are integrated by a stochastic event-based method of the OpenQuake engine to assess the regional seismic risk in terms of average annual loss and exceedance probability curve at the city,province,and regional levels.The novelty and uniqueness of this study are that a probabilistic seismic risk model for the Beijing-Tianjin-Hebei region in China is developed by considering the impact of site conditions and epistemic uncertainty from the seismic hazard model.
基金This paper was presented at "IUGG/CSB International Training Course on Continental Earthquakes and Seismic Hazard" which was held in Beijing, China on October 4 to 14, 1998.
文摘After a brief introduction of the framework of seismic risk assessment (SRA), the current state of SRA in China is presented in five parts: the vulnerability assessment of structures, SRA methodology, earthquake loss estimation, disaster management and laws, and geographical information system (GIS), with emphasis on current Chinese practice. The vulnerability matrices used are mostly from recent earthquake experiences in China, such as the 1985 Haicheng Earthquake and the 1986 Tangshen Earthquake, especially for structures such as the adobe and unreinforced masonry buildings. For SRA, different requirements are required for different scales of exposures, e.g., global scale, regional scale, city scale, and individual scale. Simple and average conditions are used for exposure estimation and seismic hazard assessment (SHA) for the global scale, and very specific and detailed conditions for the individual scale, such as for a specific engineering project. In China, there are some standardized requirements for SHA and SRA in addition to seismic design codes, which are followed.
文摘The seismicity of the Arabian plate, which is the aim of this paper, is controlled by the ZagrosTaurus collision zone in the North, the Indian expansion zone and the Arab golf in the South and the East, the Dead Sea Fault, the North continuity of the Red Sea, and the Syrian rift, which links the rigid Arabian plate to the mobile ophiolite belt of Cyprus-Southern Turkey in the West. These major elements with their related fracture system, make the Arabian plate an important seismic centre. To attain our purpose, a variable methodology is used in: measurements of movement rate-displacement in the field, the analysis of historical and recent seismic data, and physical effects on the structures. The movement rate-displacement, calculated in the field by different specialists, varies from 2 to 6 mm/year. This rate increases from 2 - 3 mm/year in the North, to 6 mm in the South. These estimations are confirmed by historical seismic data, the recent seismic recorded by the Arab seismic centers, and physical effects on the building structures in the region. The analysis of historical and recent seismic data recorded in the seismic centre show that the seismicity in this plate, tend to fade out with time. This result is in agreement with recent estimations on the movement rate, and in line with the decrease of major seismic intensity, which has occurred during the last millennium. A conclusion of time-evolution seismicity is traced, and a seismic zoning map, for the Arabian plate, using movement rate, seismic data, and tectono-geodynamic analysis, is proposed.
文摘The paper discusses how to approach the problem of the social mitigation of seismic risk, in order to reduce damage and grief consequent to earthquakes. An alert protocol, intended as a working hypothesis, is proposed based on the experience gained from analysis of the behaviour and social response to the threat before and after the great disaster of the L’Aquila earthquake on 6th April 2009. Authors propose a protocol addressing four levels of increasing alert based on signs of earthquake preparation and social concerns. In this sense, it works as an intensity scale and does not strictly relate to earthquake size (magnitude) or seismic hazard. The proposed alert protocol provides sensible measures for reducing vulnerability, which is the only factor that can be more or less efficiently controlled, based on structural and behavioural adjustments. Factors indicating the difficult relationship between politicians, scientific community and citizens are considered: 1) a serious gap between researchers and citizens;2) measures adopted by local administrators and the National Civil Protection Service not agreed by the population;3) misunderstanding originated from a lack of clarity of communication about scientific terminology;and 4) the lack of an alert procedure protocol. In the current situation, all these problems are crucial and contribute to the unpreparedness to face a seismic event, and thus greatly increase the risk. The adoption and implementation of an alert procedure protocol requires a preliminary assessment of the context and should be adapted to the local sensibility and culture. The application of a protocol may reduce the contrasts between preventive measures and individual responsibilities, making mitigation measures more feasible and socially acceptable. In this paper, risk evaluation is not strictly related to probabilistic or deterministic predictions. In fact, this is a result of a project that comes from the general analysis of risk and is not intended to give an alternative hazard estimate method. This paper proposes an alert protocol addressing four levels of increasing alert based on signs of earthquake generating preparation and social concerns. Finally, there is a suggestion on how to gradually communicate the threat and get citizens involved in the risk mitigation process.
基金This project was Sponsored by the Joint Earthquake Science Foundation, China.
文摘During the preparation process of a great earthquake, there are certain patterns of less randomness but more order in the space-time distribution of micro-earthquakes, which had been proved by seismic events and experiments. The information entropy concerning the dimension of the order in seismic distribution is systematically defined from the point of modern statistical physics in this paper. Relations of dynamic variations of information entropy with a strong shock occurrence time and the distribution of information with a strong shock occurrence place were approached through seismic data from the Wuqia, Xikar, Wushi, and Manasi regions in Xinjiang. It is indicated that before strong earthquakes, the value of information entropy often noticeably drops in seismic region, and generally much lower in the epicentral area than the surrounding regions. These two characters are of important significance in strong shock risk region determination and large shock tendency prediction.
文摘Based on the site historical earthquake data,a method of seismic risk analysis is presented.Once the frequency of earthquake response intensity and the relative value showed a logarithmic linear,the maximum similarity method would be used to obtain β,λ,and Imax,and also achieve the results of risk analysis on each site.At the same time,the "logic tree" method can be used to calibrate the uncertainty of the risk on each site.Then the final results of risk analysis indicate that this method is feasible,particularly for the sites showing intensity anomaly.
文摘The article has been retracted due to the investigation of complaints received against it. The paper is withdrawn due to paper duplication which has been published by the author years before. This paper published in Vol.1 No.1 1-12 (pages), 2012, has been removed from this site.
文摘A complete research of seismic risk assessment is presented herein focused on the existing build- ings of the extended urban region of Athens in Greece. The seismic risk assessment is fulfilled by discriminating the current study in two approaches, probable and actual, conducting afterwards between them a comparison analysis. In the first part, a pilot methodology is developed for the seismic loss assessment in monetary terms regarding the buildings damages, consistent with the National Programme for Earthquake Management of Existing Buildings (NPEMEB). The building stock consists of typical building types of Southern Europe and refers to 750,085 buildings (18.80% of buildings in Greece) situated in the entire region of Athens according to the results of the 2000-1 statistical census. A wider research of seismic risk assessment could include direct losses of infrastructures and indirect economic losses. The evaluation of loss due to building damage in a certain region requires an assessment of both seismic hazard and vulnerability of the building stock in the study area. Four different existing damage scenarios are applied for the vulnerability assessment. The results of the seismic risk assessment for the four different aspects of the es- timated damage and the different soil conditions are presented in a map of the study region. The existing vulnerability curves corresponding to defined types of buildings have been derived from the National Technical Chamber of Greece and also from recently developed DPMs. The last DPMs were obtained in a previous research (Eleftheriadou, 2009) from the process of a created damage database after the 7th of September 1999 Parnitha’s earthquake and comprised 180,945 buildings which developed damage of varying degree, type and extent. In the second part of the research, the seismic risk is evaluated from the available data regarding the mean statistical repair/ strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the same (1999 Parnitha’s) seismic event. Data regarding the compatible (budget approved according to the ministry’s provisions) repair cost has been collected. The structural losses in monetary terms for the 180,427 buildings damaged structures are evaluated equal to 2450.0 Μ€, 1887.8 Μ€ and 2118.9 Μ€ based on the previously mentioned statistical seismic risk data. The statistically derived repair cost for Attica is compared with the results of the economic loss esti- mation for buildings using the aforementioned risk assessment methodology. From the analysis results, the seismic scenario based on the recently developed DPMs (Eleftheriadou, 2009) pre- sented the better correlation (2627.77 M€) with the total statistically evaluated repair cost (2450.02 M€). It is important to stress that the inclusion of the coefficient parameter S overes- timates significantly the seismic losses. The last result should be taken into consideration in future risk researches. The comparison of the estimated economic loss with the statistical repair cost calibrates the reliability of the commonly used risk assessment method and serves in the im- provement of seismic security prioritizing the criteria for seismic rehabilitation programmes of existing buildings.
文摘The seismic risk analysis method and some special aspects concerning its application to ocean oil platforms are reviewed briefly through an example of analysis for the oil platforms in the Bohai sea. In view of the features of temporal and spatial distribution of earthquakes in China, it is emphasized that the temporal and spatial inhomogeneity of seismicity should be thoroughly studied when dealing with a specific project where a short service life and a high degree of safety are required.
