A statistical model is developed to estimate the seismic vulnerability of low- to mid-rise reinfo... more A statistical model is developed to estimate the seismic vulnerability of low- to mid-rise reinforced concrete buildings. The model is based on a novel utilization of the discriminant analysis technique of multivariate statistics. Number of stories above the ground level (N), soft story index (SSI), overhang ratio (OHR), minimum normalized lateral stiffness index (MNLSTFI), minimum normalized lateral strength index (MNLSI) and normalized redundancy score (NRS) are selected as the basic estimation variables. The earthquake damage data compiled for the 12 November 1999 Duzce earthquake are used to develop a discriminant function in terms of these estimation variables. The discriminant score obtained from the resulting discriminant function is then used to estimate the damage state of buildings ranging from no damage to collapse, with intermediate damage states of light, moderate and severe. Correct classification rates ranging between 62% and 95% obtained for the seismic damage data associated with the recent earthquakes that occurred in Turkey support the predictive ability of the proposed model.
A probabilistic method is described for estimating the earthquake hazard associated with potentia... more A probabilistic method is described for estimating the earthquake hazard associated with potentially active faults. The methodology used in this study is based on a random field model developed for the assessment of seismic hazard along linearly extending seismic sources, like faults with well defined geometry.
Abstract: A simple probabilistic model is presented to obtain a realistic estimate of earthquake ... more Abstract: A simple probabilistic model is presented to obtain a realistic estimate of earthquake insurance rates for buildings in Turkey. The model integrates information on seismic hazard and information on expected earthquake damage on engineering facilities in a systematic way, yielding estimates of earthquake insurance rates. Earthquake insurance rates are computed for reinforced concrete buildings constructed in different seismic zones of Turkey with the purpose of checking the validity of the currently charged earthquake insurance rates. The actual implementation of earthquake insurance is also discussed in this chapter. In this respect, an overview of the compulsory earthquake insurance scheme is presented, and the organizational structure and operational details of Turkish Catastrophic Insurance Pool (TCIP) are described.
Spatial sensitivity of seismic hazard results to different models with respect to background seis... more Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, involving the assessment of seismic hazard for the Bursa province in Turkey, is conducted in order to examine quantitatively the influence of these models on seismic hazard results. The spatial variation of the difference in Peak Ground Acceleration (PGA) values obtained from these different models is presented in the form of difference maps for return periods of 475 and 2475 years. Best estimate seismic hazard maps for PGA and Spectral Accelerations (SA) at 0.2 and 1.0 s are obtained by using the logic tree method.
ABSTRACT Due to uncertainties involved both in the occurrence of earthquakes and in structural re... more ABSTRACT Due to uncertainties involved both in the occurrence of earthquakes and in structural response, earthquake damage prediction has to be treated in a probabilistic manner. In this study two statistical methods are presented for the prediction of potential seismic damage to low and mid-rise reinforced concrete buildings in Turkey. These methods are based on the utilization of damage probability matrices and reliability theory. The damage data compiled during recent earthquakes that occurred in Turkey are used to compare the predictions of these two methods. Key wordsEarthquake damage estimation, damage probability matrix, fragility curves, seismic resistance index, reliability theory, Diizce earthquake
Probabilistic methods are used to quantify the seismic hazard in Jordan and neighbouring regions.... more Probabilistic methods are used to quantify the seismic hazard in Jordan and neighbouring regions. The hazard model incorporates the uncertainties associated with the seismicity parameters and the attenuation equation. Seven seismic sources are identified in the region and the seismicity parameters of these sources are estimated by making use of all the available information. Seismic hazard computations and the selection of peak ground acceleration and modified Mercalli intensity values at the nodes of a 25 x 25 km mesh covering the region under study are carried out by two different computer programs. The results of the study are presented through a set of seismic hazard maps displaying iso-acceleration and iso-intensity contours corresponding to specified return periods. The first set of maps is derived based on the seismicity data assessed in this study and display our 'best' estimate of the seismic hazard for Jordan and the neighbouring areas. The second set of maps which shows the 'alternative' estimate of seismic hazard is based solely on the seismicity parameters reported by other researchers. The third set of maps, called the 'Bayesian' estimate of seismic hazard, reflects the influence of expert opinion involving more conservative assumptions regarding the Red Sea and Araba faults.
ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, Sep 1, 2018
AbstractAssessment of the reliability of lifelines under seismic loads requires particular attent... more AbstractAssessment of the reliability of lifelines under seismic loads requires particular attention, since the proper functioning of these systems during or after a destructive earthquake is very ...
ABSTRACT Influence of different models and assumptions with respect to seismic source modelling a... more ABSTRACT Influence of different models and assumptions with respect to seismic source modelling and magnitude distribution on seismic hazard results is examined, taking Jordan as a case study. Four alternative models, which are based on different combinations of seismic source models and magnitude-recurrence relationships, are considered. Seismic hazard curves obtained at four different sites in Jordan according to these four models are compared. In order to display the magnitude of spatial variation of peak ground acceleration (PGA) values obtained from these models, difference maps for return periods of 475 and 2475 years are constructed. Logic tree method is applied to aggregate the results calculated based on different models and assumptions. Then, best estimate seismic hazard maps for PGA and spectral acceleration at 0.2 and 1.0 s corresponding to return periods of 475 and 2475 years are plotted.
A random field model is developed to describe the occurrence of earthquakes in the space–time dom... more A random field model is developed to describe the occurrence of earthquakes in the space–time domain. The general theory of stationary random functions is utilized to assess the seismic hazard associated with linearly extending faults. The spatial and temporal correlation characteristics of the strain energy random field are taken into consideration explicitly and particular emphasis is given to the analysis
... ST bins were determined based on the shear wave velocity (V s) of the soil types employed by ... more ... ST bins were determined based on the shear wave velocity (V s) of the soil types employed by the Turkish Seismic Code. ... The number of sites can easily be increased by incorporating other distance ranges and soil types (V s> 1000 mls). 2.2 Attenuation Models ...
Probabilistic safety evaluation of earth slopes is the most widely studied subject in geotechnica... more Probabilistic safety evaluation of earth slopes is the most widely studied subject in geotechnical reliability literature. In the majority of these studies the formulation is based on the plane strain assumption. Three-dimensional (3-D) probabilistic models of slope stability have been investigated by Peintinger and Rackwitz (3), Vanmarcke (5,6), Veneziano et al. (7) and Yucemen (8,9). These studies as well as some other deterministic analyses (see for example Mejia and Seed (2)) confirm the importance of the 3-D effects. In almost all of the previous studies only static loads were taken into consideration and the uncertainty associated with load effects were consistently ignored.
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, Jun 1, 2009
The probabilistic model of earthquake insurance analysis, which was developed earlier, is applied... more The probabilistic model of earthquake insurance analysis, which was developed earlier, is applied using effective data processing methods and recent data, to obtain realistic estimates of the earthquake insurance premium rates applicable for reinforced concrete and masonry buildings in Turkey. While doing this, the information on future earthquake threat is integrated with the information on expected earthquake damage to buildings.
The precise estimation of the a and b parameters of Richter's magnitude-frequency relationship is... more The precise estimation of the a and b parameters of Richter's magnitude-frequency relationship is of primary importance, since the evaluation of seismicity and assessment of seismic hazard depend on these two parameters. In the literature two popular methods of estimation are available for the estimation of these parameters, namely: least squares and maximum likelihood. However, in implementing these statistical methods, engineers very seldom check the validity of the underlying assumptions with respect to the available data and this may lead to serious problems. Under non-normality least squares estimators (LSEs) are neither efficient nor robust and maximum likelihood estimators (MLEs) are elusive due to numerous complexities. A robust estimation procedure, the modified maximum likelihood method (MML), can be utilized to estimate the unknown parameters a and b in such situations. The resulting estimators are explicit functions of sample observations and are shown to be considerably more efficient than the commonly used least squares estimators. In addition, we demonstrate that the MML estimators are more appropriate to estimate the parameters of Richter's magnitude-frequency relationship based on the comparison of their performance with those of the least squares estimators by using the seismic database on earthquakes recorded in Turkey.
A probabilistic model is presented for the assessment of the earthquake insurance rates for impor... more A probabilistic model is presented for the assessment of the earthquake insurance rates for important engineering structures, for which the seismic losses could be quite significant. The proposed model is used to estimate the earthquake insurance premiums for the structures taking place in the Bolu Mountain Crossing in the Gumusova–Gerede motorway Section, Turkey. The model requires two types of studies,
Reliability Engineering & System Safety, Sep 1, 1999
Lifelines, such as pipelines, transportation, communication and power transmission systems, are n... more Lifelines, such as pipelines, transportation, communication and power transmission systems, are networks which extend spatially over large geographical regions. The quantification of the reliability (survival probability) of a lifeline under seismic threat requires attention, as the proper functioning of these systems during or after a destructive earthquake is vital. In this study, a lifeline is idealized as an equivalent network
Earthquake catalogues which form the main input in seismic hazard analysis generally report earth... more Earthquake catalogues which form the main input in seismic hazard analysis generally report earthquake magnitudes in different scales. Magnitudes reported in different scales have to be converted to a common scale while compiling a seismic data base to be utilized in seismic hazard analysis. This study aims at developing empirical relationships to convert earthquake magnitudes reported in different scales, namely, surface wave magnitude, M S , local magnitude, M L , body wave magnitude, m b and duration magnitude, M d , to the moment magnitude (M w). For this purpose, an earthquake data catalogue is compiled from domestic and international data bases for the earthquakes occurred in Turkey. The earthquake reporting differences of various data sources are assessed. Conversion relationships are established between the same earthquake magnitude scale of different data sources and different earthquake magnitude scales. Appropriate statistical methods are employed iteratively, considering the random errors both in the independent and dependent variables. The results are found to be sensitive to the choice of the analysis methods. Keywords Earthquake magnitude conversion Á Moment magnitude Á Orthogonal regression Á Standard least squares regression 1 Introduction An important primary step in carrying out a seismic hazard analysis is the compilation of a comprehensive earthquake catalogue. Earthquake data can be obtained from various sources, each of which may have different ways of reporting an earthquake, different history in the development of recording instruments or different instrument spread, besides the uncertainty in the nature of earthquakes. Additionally, there exist a number of widely
A statistical model is developed to estimate the seismic vulnerability of low- to mid-rise reinfo... more A statistical model is developed to estimate the seismic vulnerability of low- to mid-rise reinforced concrete buildings. The model is based on a novel utilization of the discriminant analysis technique of multivariate statistics. Number of stories above the ground level (N), soft story index (SSI), overhang ratio (OHR), minimum normalized lateral stiffness index (MNLSTFI), minimum normalized lateral strength index (MNLSI) and normalized redundancy score (NRS) are selected as the basic estimation variables. The earthquake damage data compiled for the 12 November 1999 Duzce earthquake are used to develop a discriminant function in terms of these estimation variables. The discriminant score obtained from the resulting discriminant function is then used to estimate the damage state of buildings ranging from no damage to collapse, with intermediate damage states of light, moderate and severe. Correct classification rates ranging between 62% and 95% obtained for the seismic damage data associated with the recent earthquakes that occurred in Turkey support the predictive ability of the proposed model.
A probabilistic method is described for estimating the earthquake hazard associated with potentia... more A probabilistic method is described for estimating the earthquake hazard associated with potentially active faults. The methodology used in this study is based on a random field model developed for the assessment of seismic hazard along linearly extending seismic sources, like faults with well defined geometry.
Abstract: A simple probabilistic model is presented to obtain a realistic estimate of earthquake ... more Abstract: A simple probabilistic model is presented to obtain a realistic estimate of earthquake insurance rates for buildings in Turkey. The model integrates information on seismic hazard and information on expected earthquake damage on engineering facilities in a systematic way, yielding estimates of earthquake insurance rates. Earthquake insurance rates are computed for reinforced concrete buildings constructed in different seismic zones of Turkey with the purpose of checking the validity of the currently charged earthquake insurance rates. The actual implementation of earthquake insurance is also discussed in this chapter. In this respect, an overview of the compulsory earthquake insurance scheme is presented, and the organizational structure and operational details of Turkish Catastrophic Insurance Pool (TCIP) are described.
Spatial sensitivity of seismic hazard results to different models with respect to background seis... more Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, involving the assessment of seismic hazard for the Bursa province in Turkey, is conducted in order to examine quantitatively the influence of these models on seismic hazard results. The spatial variation of the difference in Peak Ground Acceleration (PGA) values obtained from these different models is presented in the form of difference maps for return periods of 475 and 2475 years. Best estimate seismic hazard maps for PGA and Spectral Accelerations (SA) at 0.2 and 1.0 s are obtained by using the logic tree method.
ABSTRACT Due to uncertainties involved both in the occurrence of earthquakes and in structural re... more ABSTRACT Due to uncertainties involved both in the occurrence of earthquakes and in structural response, earthquake damage prediction has to be treated in a probabilistic manner. In this study two statistical methods are presented for the prediction of potential seismic damage to low and mid-rise reinforced concrete buildings in Turkey. These methods are based on the utilization of damage probability matrices and reliability theory. The damage data compiled during recent earthquakes that occurred in Turkey are used to compare the predictions of these two methods. Key wordsEarthquake damage estimation, damage probability matrix, fragility curves, seismic resistance index, reliability theory, Diizce earthquake
Probabilistic methods are used to quantify the seismic hazard in Jordan and neighbouring regions.... more Probabilistic methods are used to quantify the seismic hazard in Jordan and neighbouring regions. The hazard model incorporates the uncertainties associated with the seismicity parameters and the attenuation equation. Seven seismic sources are identified in the region and the seismicity parameters of these sources are estimated by making use of all the available information. Seismic hazard computations and the selection of peak ground acceleration and modified Mercalli intensity values at the nodes of a 25 x 25 km mesh covering the region under study are carried out by two different computer programs. The results of the study are presented through a set of seismic hazard maps displaying iso-acceleration and iso-intensity contours corresponding to specified return periods. The first set of maps is derived based on the seismicity data assessed in this study and display our 'best' estimate of the seismic hazard for Jordan and the neighbouring areas. The second set of maps which shows the 'alternative' estimate of seismic hazard is based solely on the seismicity parameters reported by other researchers. The third set of maps, called the 'Bayesian' estimate of seismic hazard, reflects the influence of expert opinion involving more conservative assumptions regarding the Red Sea and Araba faults.
ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, Sep 1, 2018
AbstractAssessment of the reliability of lifelines under seismic loads requires particular attent... more AbstractAssessment of the reliability of lifelines under seismic loads requires particular attention, since the proper functioning of these systems during or after a destructive earthquake is very ...
ABSTRACT Influence of different models and assumptions with respect to seismic source modelling a... more ABSTRACT Influence of different models and assumptions with respect to seismic source modelling and magnitude distribution on seismic hazard results is examined, taking Jordan as a case study. Four alternative models, which are based on different combinations of seismic source models and magnitude-recurrence relationships, are considered. Seismic hazard curves obtained at four different sites in Jordan according to these four models are compared. In order to display the magnitude of spatial variation of peak ground acceleration (PGA) values obtained from these models, difference maps for return periods of 475 and 2475 years are constructed. Logic tree method is applied to aggregate the results calculated based on different models and assumptions. Then, best estimate seismic hazard maps for PGA and spectral acceleration at 0.2 and 1.0 s corresponding to return periods of 475 and 2475 years are plotted.
A random field model is developed to describe the occurrence of earthquakes in the space–time dom... more A random field model is developed to describe the occurrence of earthquakes in the space–time domain. The general theory of stationary random functions is utilized to assess the seismic hazard associated with linearly extending faults. The spatial and temporal correlation characteristics of the strain energy random field are taken into consideration explicitly and particular emphasis is given to the analysis
... ST bins were determined based on the shear wave velocity (V s) of the soil types employed by ... more ... ST bins were determined based on the shear wave velocity (V s) of the soil types employed by the Turkish Seismic Code. ... The number of sites can easily be increased by incorporating other distance ranges and soil types (V s> 1000 mls). 2.2 Attenuation Models ...
Probabilistic safety evaluation of earth slopes is the most widely studied subject in geotechnica... more Probabilistic safety evaluation of earth slopes is the most widely studied subject in geotechnical reliability literature. In the majority of these studies the formulation is based on the plane strain assumption. Three-dimensional (3-D) probabilistic models of slope stability have been investigated by Peintinger and Rackwitz (3), Vanmarcke (5,6), Veneziano et al. (7) and Yucemen (8,9). These studies as well as some other deterministic analyses (see for example Mejia and Seed (2)) confirm the importance of the 3-D effects. In almost all of the previous studies only static loads were taken into consideration and the uncertainty associated with load effects were consistently ignored.
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, Jun 1, 2009
The probabilistic model of earthquake insurance analysis, which was developed earlier, is applied... more The probabilistic model of earthquake insurance analysis, which was developed earlier, is applied using effective data processing methods and recent data, to obtain realistic estimates of the earthquake insurance premium rates applicable for reinforced concrete and masonry buildings in Turkey. While doing this, the information on future earthquake threat is integrated with the information on expected earthquake damage to buildings.
The precise estimation of the a and b parameters of Richter's magnitude-frequency relationship is... more The precise estimation of the a and b parameters of Richter's magnitude-frequency relationship is of primary importance, since the evaluation of seismicity and assessment of seismic hazard depend on these two parameters. In the literature two popular methods of estimation are available for the estimation of these parameters, namely: least squares and maximum likelihood. However, in implementing these statistical methods, engineers very seldom check the validity of the underlying assumptions with respect to the available data and this may lead to serious problems. Under non-normality least squares estimators (LSEs) are neither efficient nor robust and maximum likelihood estimators (MLEs) are elusive due to numerous complexities. A robust estimation procedure, the modified maximum likelihood method (MML), can be utilized to estimate the unknown parameters a and b in such situations. The resulting estimators are explicit functions of sample observations and are shown to be considerably more efficient than the commonly used least squares estimators. In addition, we demonstrate that the MML estimators are more appropriate to estimate the parameters of Richter's magnitude-frequency relationship based on the comparison of their performance with those of the least squares estimators by using the seismic database on earthquakes recorded in Turkey.
A probabilistic model is presented for the assessment of the earthquake insurance rates for impor... more A probabilistic model is presented for the assessment of the earthquake insurance rates for important engineering structures, for which the seismic losses could be quite significant. The proposed model is used to estimate the earthquake insurance premiums for the structures taking place in the Bolu Mountain Crossing in the Gumusova–Gerede motorway Section, Turkey. The model requires two types of studies,
Reliability Engineering & System Safety, Sep 1, 1999
Lifelines, such as pipelines, transportation, communication and power transmission systems, are n... more Lifelines, such as pipelines, transportation, communication and power transmission systems, are networks which extend spatially over large geographical regions. The quantification of the reliability (survival probability) of a lifeline under seismic threat requires attention, as the proper functioning of these systems during or after a destructive earthquake is vital. In this study, a lifeline is idealized as an equivalent network
Earthquake catalogues which form the main input in seismic hazard analysis generally report earth... more Earthquake catalogues which form the main input in seismic hazard analysis generally report earthquake magnitudes in different scales. Magnitudes reported in different scales have to be converted to a common scale while compiling a seismic data base to be utilized in seismic hazard analysis. This study aims at developing empirical relationships to convert earthquake magnitudes reported in different scales, namely, surface wave magnitude, M S , local magnitude, M L , body wave magnitude, m b and duration magnitude, M d , to the moment magnitude (M w). For this purpose, an earthquake data catalogue is compiled from domestic and international data bases for the earthquakes occurred in Turkey. The earthquake reporting differences of various data sources are assessed. Conversion relationships are established between the same earthquake magnitude scale of different data sources and different earthquake magnitude scales. Appropriate statistical methods are employed iteratively, considering the random errors both in the independent and dependent variables. The results are found to be sensitive to the choice of the analysis methods. Keywords Earthquake magnitude conversion Á Moment magnitude Á Orthogonal regression Á Standard least squares regression 1 Introduction An important primary step in carrying out a seismic hazard analysis is the compilation of a comprehensive earthquake catalogue. Earthquake data can be obtained from various sources, each of which may have different ways of reporting an earthquake, different history in the development of recording instruments or different instrument spread, besides the uncertainty in the nature of earthquakes. Additionally, there exist a number of widely
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