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1.
Modification of stochastic ground motion models for matching target intensity measures 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Stochastic ground motion models produce synthetic time‐histories by modulating a white noise sequence through functions that address spectral and temporal properties of the excitation. The resultant ground motions can be then used in simulation‐based seismic risk assessment applications. This is established by relating the parameters of the aforementioned functions to earthquake and site characteristics through predictive relationships. An important concern related to the use of these models is the fact that through current approaches in selecting these predictive relationships, compatibility to the seismic hazard is not guaranteed. This work offers a computationally efficient framework for the modification of stochastic ground motion models to match target intensity measures (IMs) for a specific site and structure of interest. This is set as an optimization problem with a dual objective. The first objective minimizes the discrepancy between the target IMs and the predictions established through the stochastic ground motion model for a chosen earthquake scenario. The second objective constraints the deviation from the model characteristics suggested by existing predictive relationships, guaranteeing that the resultant ground motions not only match the target IMs but are also compatible with regional trends. A framework leveraging kriging surrogate modeling is formulated for performing the resultant multi‐objective optimization, and different computational aspects related to this optimization are discussed in detail. The illustrative implementation shows that the proposed framework can provide ground motions with high compatibility to target IMs with small only deviation from existing predictive relationships and discusses approaches for selecting a final compromise between these two competing objectives. 相似文献
2.
Paul W. Burton Yebang Xu G. -Akis Tselentis Ethimios Sokos Willy Aspinall 《Soil Dynamics and Earthquake Engineering》2003,23(2):159-181
In an early paper [Tectonophysics 117 (1985) 259] seismic hazard in Greece was analyzed using a relatively homogeneous earthquake catalogue spanning 1900–1978 and a strong motion attenuation relationship adapted to use in Greece. Improved seismic hazard analyses are obtained here using Gumbel's asymptotic extreme value distribution applied to peak horizontal ground acceleration occurrence, but now taking into account the increased length and quality of earthquake catalogue data spanning 1900–1999 and the burgeoning information on earthquake strong motion data and attenuation relationships appropriate for Europe and, explicitly, Greece. Seismic acceleration hazard results tabulated for six cities reveal (e.g. using arbitrarily the 50-year p.g.a. with 90% probability of not being exceeded) changes of about 10% in the new calculated values: two cities show an increase and four a decrease. These are relatively small and reassuring adjustments.Inspection of the available attenuation relationships leads to a preference for the models of Theodulidis and Papazachos, particularly with the model modification to produce a ‘stiff soil’ site relationship, as these relationships explicitly exploit the Greek strong motion database. Isoacceleration maps are produced for Greece as a whole from each attenuation relationship inspected. The final set of maps based on the Theodulidis and Papazachos models provide a foundation for comparison with the Seismic Hazard Zones adopted in the New Greek Seismic Code where scope can be found to modify zone shape and the level at which p.g.a.s are set. It should be noted that the generation of the present isoacceleration maps is based on a seismogenic zone-free methodology, independent of any Euclidean zoning assumptions. 相似文献
3.
Robin K. McGuire 《地震工程与结构动力学》1977,5(3):211-234
The calculation of design spectra for building sites threatened by seismic ground motion is approached by considering the maximum responses of linearly elastic oscillators as indicators of ground motion intensity. Attenuation functions describing the distribution of response as a function of earthquake magnitude and distance are derived using 68 components of recorded ground motion as data. With a seismic hazard analysis for several hypothetical building sites, the distributions of maximum oscillator responses to earthquakes of random magnitude and location are calculated, and spectra are drawn to indicate the maximum responses associated with specified probability levels. These spectra are compared to design spectra calculated from published methods of amplifying peak ground motion parameters. The latter spectra are found to be inconsistent in terms of risk for building sites very close and very far from faults. A ground motion parameter defined to be proportional to the maximum response of a 1 Hz, 2 per cent damped linearly elastic oscillator is investigated; this parameter, in conjunction with peak ground acceleration, is found to lead to risk-consistent design spectra. Through these two parameters, a design earthquake magnitude and design hypocentral distance are defined, for a specified building site and risk level. The use of these parameters in the seismic hazard mapping of a region is illustrated. 相似文献
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A comparative study of risk assessment methodologies based on macroseismic intensity and response spectrum approaches is presented. To facilitate the comparative study, a spreadsheet-based software tool ‘SeisVARA’ is developed for the estimation of earthquake risk, in which the seismic hazard can be specified either in terms of macroseismic intensity, or peak ground acceleration in combination with the spectral shape and soil amplification model of various earthquake building codes, or in terms of inelastic response spectra using the ‘next generation attenuation relationships’. A comparison of these different approaches is conducted for a typical city in northern India. In addition, the effect of different parameters, e.g., level of PGA, spectral shape, source-site parameters, and soil amplification models, is studied. It is observed that not only the different approaches result in widely varying damage and loss estimates, but also the variation of parameters within a given approach can result in considerable differences. 相似文献
6.
Fragility curves constitute the cornerstone in seismic risk evaluations and performance-based earthquake engineering. They describe the probability of a structure to experience a certain damage level for a given earthquake intensity measure, providing a relationship between seismic hazard and vulnerability. In this paper a numerical approach is applied to derive fragility curves for tunnel shafts built in clays, a component that is found in several critical infrastructure such as urban metro networks, airport facilities or water and waste water projects. The seismic response of a representative tunnel shaft is assessed using tridimensional finite difference non-linear analyses carried out with the program FLAC3D, under increasing levels of seismic intensity. A hysteretic model is used to simulate the soil non-linear behavior during the seismic event. The effect of soil conditions and ground motion characteristics on the soil-structure system response is accounted for in the analyses. The damage is defined based on the exceedance of the concrete wall shaft capacity due to the developed seismic forces. The fragility curves are estimated in terms of peak ground acceleration at a rock or stiff soil outcrop, based on the evolution of damage with increasing earthquake intensity. The proposed fragility models allows the characterization of the seismic risk of a representative tunnel shaft typology and soil conditions considering the associated uncertainties, and partially fill the gap of data required in performing a risk analysis assessment of tunnels shafts. 相似文献
7.
Intensity-based seismic risk assessment 总被引：1，自引：0，他引：1
8.
K. W. Campbell P. C. Thenhaus T. P. Barnhard D. B. Hampson 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):743-754
We developed a seismic hazard model for Taiwan that integrates all available tectonic, seismicity, and seismic hazard information in the region to provide risk managers and engineers with a model they can use to estimate earthquake losses and manage seismic risk in Taiwan. The seismic hazard model is composed of two major components: a seismotectonic model and a ground-shaking model. The seismotectonic model incorporates earthquakes that are expected to occur on the Ryukyu and Manila subduction zones, on the intermediate-depth Wadati-Benioff seismicity zones, on the active crustal faults, and within seismotectonic provinces. The active crustal faults include the Chelungpu fault zone, the source of the damaging MW 7.6 Chi-Chi earthquake, and the Huangchi-Hsiaoyukeng fault zone that forms the western boundary of the Taipei Basin. The ground-shaking model uses both US, worldwide, and Taiwanese attenuation relations to provide robust estimates of peak ground acceleration and response spectral acceleration on a reference site condition for shallow crustal and subduction zone earthquakes. The ground shaking for other site conditions is obtained by applying a nonlinear soil-amplification factor defined in terms of the average shear-wave velocity in the top 30 m of the soil profile, consistent with the methodology used in the current US and proposed Taiwan building codes. 相似文献
9.
Probabilistic seismic hazard assessment for Thailand 总被引：3，自引：1，他引：2
Teraphan Ornthammarath Pennung Warnitchai Kawin Worakanchana Saeed Zaman Ragnar Sigbj?rnsson Carlo Giovanni Lai 《Bulletin of Earthquake Engineering》2011,9(2):367-394
A set of probabilistic seismic hazard maps for Thailand has been derived using procedures developed for the latest US National
Seismic Hazard Maps. In contrast to earlier hazard maps for this region, which are mostly computed using seismic source zone
delineations, the presented maps are based on the combination of smoothed gridded seismicity, crustal-fault, and subduction
source models. Thailand’s composite earthquake catalogue is revisited and expanded, covering a study area limited by 0°–30°N
Latitude and 88°–110°E Longitude and the instrumental period from 1912 to 2007. The long-term slip rates and estimates of
earthquake size from paleoseismological studies are incorporated through a crustal fault source model. Furthermore, the subduction
source model is used to model the megathrust Sunda subduction zones, with variable characteristics along the strike of the
faults. Epistemic uncertainty is taken into consideration by the logic tree framework incorporating basic quantities, such
as different source modelling, maximum cut-off magnitudes and ground motion prediction equations. The ground motion hazard
map is presented over a 10 km grid in terms of peak ground acceleration and spectral acceleration at 0.2, 1.0, and 2.0 undamped
natural periods and a 5% critical damping ratio for 10 and 2% probabilities of exceedance in 50 years. The presented maps
give expected ground motions that are based on more extensive data sources than applied in the development of previous maps.
The main findings are that northern and western Thailand are subjected to the highest hazard. The largest contributors to
short- and long-period ground motion hazard in the Bangkok region are from the nearby active faults and Sunda subduction zones,
respectively. 相似文献
10.
Safety against earthquake hazards presents two aspects: structural safety against potentially destructive dynamic forces and site safety related to geotechnical phenomena, such as amplification, landsliding and soil liquefaction. The correct evaluation of seismic hazard is, therefore, highly affected by risk factors due to geological nature and geotechnical properties of soils. In response to these new developments, several attempts have been made to identify and appraise geotechnical hazards and to represent them in the form of zoning maps, in which locations or zones with different levels of hazard potential are identified. The geotechnical zonation of the subsoil of the city of Catania (Italy) suggests a high vulnerability of the physical environment added to site amplification of the ground motion phenomena. The ground response analysis at the surface, in terms of time history and response spectra, has been obtained by some 1D equivalent linear models and by a 2D linear model, using a design scenario earthquake as input at the conventional bedrock. In particular, the study has regarded the evaluation of site effects in correspondence of the database of about 1200 boreholes and water-wells available in the data-bank of the Catania area. According to the response spectra obtained through the application of the 1D and 2D models, the city of Catania has been divided into some zones with different peak ground acceleration at the surface, to which corresponds a different value of the Seismic Geotechnical Hazard. A seismic microzoning map of the urban area of the city of Catania has been obtained. The map represents an important tool for the seismic improvement of the buildings, indispensable for the mitigation of the seismic risk. 相似文献
11.
Seismic risk assessment requires adoption of appropriate models for the earthquake hazard, the structural system and for its performance, and quantification of the uncertainties involved in these models through appropriate probability distributions. Characterization of the seismic hazard comprises undoubtedly the most critical component of this process, the one associated with the largest amount of uncertainty. For applications involving dynamic analysis this hazard is frequently characterized through stochastic ground motion models. This paper discusses a novel, global sensitivity analysis for the seismic risk with emphasis on such a stochastic ground motion modeling. This analysis aims to identify the overall (i.e. global) importance of each of the uncertain model parameters, or of groups of them, towards the total risk. The methodology is based on definition of an auxiliary density (distribution) function, proportional to the integrand of the integral quantifying seismic risk, and on comparison of this density to the initial probability distribution for the model parameters of interest. Uncertainty in the rest of the model parameters is explicitly addressed through integration of their joint auxiliary distribution to calculate the corresponding marginal distributions. The relative information entropy is used to quantify the difference between the compared density functions and an efficient approach based on stochastic sampling is introduced for estimating this entropy for all quantities of interest. The framework is illustrated in an example that adopts a source-based stochastic ground motion model, and valuable insight is provided for its implementation within structural engineering applications. 相似文献
12.
利用华北地区地震活动性资料,建立了地震危险性计算的一致性模型.在此模型的基础上,得出了北京、天津、唐山和济南等7个城市未来2500年内地震的时空强度分布,并计算了2500年回复周期的地震动峰值加速度(PGA).结果表明,唐山和太原的PGA最大(>0.2g),石家庄和北京次之(≈0.17g).对华北地区2500年地震记录的正演计算结果表明,太原和唐山地区的潜在地震危险最有可能来源于震级在6.0～7.0、震中距离在12～15km的地震活动;而北京、天津和石家庄地区则可能来源于震级在5.5～6.0、震中距离在10km左右的地震活动.采用IBC(International Building Code)方法计算后的结果显示,太原、唐山等地区的PGA与2001年我国地震动峰值加速度值基本一致,与此地区的较高地震活动性特征相符.利用随机震源模型,还给出了影响此7个城市的最大地震记录的加速度、速度及位移时程曲线,这对本区工程建筑的抗震性设计以及对救援设施的选址等有重要作用. 相似文献
13.
R. Secanell D. Bertil C. Martin X. Goula T. Susagna M. Tapia P. Dominique D. Carbon J. Fleta 《Journal of Seismology》2008,12(3):323-341
A unified probabilistic seismic hazard assessment (PSHA) for the Pyrenean region has been performed by an international team
composed of experts from Spain and France during the Interreg IIIA ISARD project. It is motivated by incoherencies between
the seismic hazard zonations of the design codes of France and Spain and by the need for input data to be used to define earthquake
scenarios. A great effort was invested in the homogenisation of the input data. All existing seismic data are collected in
a database and lead to a unified catalogue using a local magnitude scale. PSHA has been performed using logic trees combined
with Monte Carlo simulations to account for both epistemic and aleatory uncertainties. As an alternative to hazard calculation
based on seismic sources zone models, a zoneless method is also used to produce a hazard map less dependant on zone boundaries.
Two seismogenic source models were defined to take into account the different interpretations existing among specialists.
A new regional ground-motion prediction equation based on regional data has been proposed. It was used in combination with
published ground-motion prediction equations derived using European and Mediterranean data. The application of this methodology
leads to the definition of seismic hazard maps for 475- and 1,975-year return periods for spectral accelerations at periods
of 0 (corresponding to peak ground acceleration), 0.1, 0.3, 0.6, 1 and 2 s. Median and percentiles 15% and 85% acceleration
contour lines are represented. Finally, the seismic catalogue is used to produce a map of the maximum acceleration expected
for comparison with the probabilistic hazard maps. The hazard maps are produced using a grid of 0.1°. The results obtained
may be useful for civil protection and risk prevention purposes in France, Spain and Andorra. 相似文献
14.
新版地震区划图地震活动性模型与参数确定 总被引：11，自引：4，他引：7
地震活动性模型和地震动预测模型是概率地震危险性分析的两个核心。在新版地震区划图中,依据板内地震活动空间不均匀性分布的特点,在概率地震危险性分析方法(CPSHA)中采用了由地震统计区、背景潜在震源区和构造潜在震源区构成的三级层次性潜在震源区模型,并构建了相应的地震活动性模型。本文在论述CPSHA方法及其地震活动性模型基本概念的基础上,重点介绍了新版地震区划图地震活动性模型的三级潜在震源区模型的构成、地震活动性假定和基本特点,同时,也对新版地震区划图地震活动性模型的重要参数确定思路、方法与结果进行了介绍。本文将为更好地认识与理解我国新版地震动参数区划图提供有益的参考。 相似文献
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An energy-based envelope function is developed for use in the stochastic simulation of earthquake ground motion. The envelope function is directly related to the Arias intensity of the ground motion as well to the manner in which this Arias intensity is built-up over time. It is shown that this build-up, represented by a Husid plot, can be very well modelled using a simple lognormal distribution. The proposed envelope makes use of parameters that are commonly available in seismic design situations, either following a deterministic scenario-type analysis or following a more comprehensive probabilistic seismic hazard analysis (PSHA), either in terms of Arias intensity or the more common spectral acceleration. The shape parameters of the envelope function are estimated following the calculation of the analytic envelopes for a large number of records from PEER Next Generation of Attenuation (NGA) database. The envelope may also be used to predict the distribution of peak ground acceleration values corresponding to an earthquake scenario. The distribution thus obtained is remarkably consistent with those of the recent NGA models. 相似文献
17.
Fourier-amplitude spectrum is one of the most important parameters describing earthquake ground motion, and it is widely used for strong ground motion prediction and seismic hazard estimation. The relationships between Fourier-acceleration spectra, earthquake magnitude and distance were analysed for different seismic regions (the Caucasus and Taiwan island) on the basis of ground motion recordings of small to moderate (3.5≤ML≤6.5) earthquakes. It has been found that the acceleration spectra of the most significant part of the records, starting from S-wave arrival, can be modelled accurately by the Brune's “ω-squared” point-source model. Parameters of the model are found to be region-dependent. Peak ground accelerations and response spectra for condition of rock sites were calculated using stochastic simulation technique and obtained models of source spectra. The modelled ground-motion parameters are compared with those predicted by recent empirical attenuation relationship for California. 相似文献
18.
传统考虑后期使用年限的地震动参数研究,在建筑物抗震设计中的应用,缺乏地震危险性分析和建筑物损伤指数分析,应用性差。提出新的地震动参数在建筑物抗震设计中的应用方法,以地震危险性分析为基础,通过水平地震动加速度衰减关系方程,求得建筑场地水平向基岩峰值加速度和反应谱,以此得到地震动加速度反应谱方程,利用该方程获得地震动反应谱参数,采用变形和线性组合构建损伤指数模型,获取地震波作用下地震动参数对建筑物损伤程度。实验结果表明,利用所提方法得到的地震动反应谱最小误差为0.563,小于允许误差4.0;在50年超越概率63%的条件下地震动参数值分别为0.26、0.095,所提方法可在规定误差范围内得到地震动反应谱参数值,其进行建筑物抗震设计精度和应用性高。 相似文献
19.
Fully probabilistic seismic displacement analysis of spatially distributed slopes using spatially correlated vector intensity measures 下载免费PDF全文
下载免费PDF全文 Earthquake‐induced slope displacement is an important parameter for safety evaluation and earthquake design of slope systems. Traditional probabilistic seismic hazard analysis usually focuses on evaluating slope displacement at a particular location, and it is not suitable for spatially distributed slopes over a large region. This study proposes a computationally efficient framework for fully probabilistic seismic displacement analysis of spatially distributed slope systems using spatially correlated vector intensity measures (IMs). First, a spatial cross‐correlation model for three key ground motion IMs, that is, peak ground acceleration (PGA), Arias intensity, and peak ground velocity, is developed using 2686 ground motion recordings from 11 recent earthquakes. To reduce the computational cost, Monte Carlo simulation and data reduction techniques are utilized to generate spatially correlated random fields for the vector IMs. The slope displacement hazards over the region are further quantified using empirical predictive equations. Finally, an illustrative example is presented to highlight the importance of the spatial correlation and the advantage of using spatially correlated vector IMs in seismic hazard analysis of spatially distributed slopes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
20.
Aníbal Ojeda Kuvvet Atakan Eullia Masana Pere Santanach María-Jos Jimnez Mariano García-Fernndez 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):911-916
In this study, the influence of paleoseismic and geologic data in the seismic hazard estimation for the Catalan coastal ranges is analysed. We computed the probabilistic seismic hazard using area seismic sources with a Poissonian assumption for the earthquake occurrence. For the computations, a previously published attenuation relationship based on European strong motion data was applied. The resulting hazard estimates show similarities to the previous assessments in the region. These results were then used as a reference for comparison with other new models. In order to analyse the influence of the paleoseismic data three different models were tested. Since the number of faults that are investigated in detail are few, the same area sources that were used in the Poissonian assumption were kept in all three new models. In addition, the new paleoseismic data with faults expressed as line sources were used. In this case, a cyclic earthquake occurrence was assumed. The three models were based on the paleoseismic data with different assumptions on the time elapsed since last event. The time elapsed was set to 0, 10 and 85% of the recurrence interval in each model. The results are presented as maps showing the difference between the three models and the reference model with the Poissonian assumption. The results are given in horizontal peak ground acceleration contour maps for different return periods, also taking into account large return periods as high as 25,000 years. This is done to demonstrate the effect of large recurrence intervals found for some of the active faults. In general, we observe that for short return periods (<1000 years), the Poissonian assumption of earthquake occurrence is probably sufficient and provides a robust estimate of the hazard. However, for longer return periods (>5000 years) the effects of the paleoseismic data become increasingly significant. In order to estimate the true seismic hazard potential of this apparently low seismicity area, long-term behaviour of the possible active faults in the region needs to be investigated systematically. 相似文献