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1.
潜在震源区地震活动性参数、地震动衰减关系对地震危险性分析结果至关重要。以中国第五代地震动区划图潜在震源区划分方案为基础,采用2类震级分档分别建立自编及五代图潜在震源区空间分布函数,收集4组青藏高原及周缘地区地震动衰减关系,采用不同组合对青藏工程走廊沿线的81个场点进行概率地震危险性分析计算,得到50年超越概率10%(地震重现期475年)的各场点基岩地震动峰值加速度(PGA),并转换为一般场地(Ⅱ类)PGA,对计算结果进行对比分析,并与第五代地震动区划图归档上下限值进行比较。结果显示:采用我国西部地区地震动衰减关系计算得到的PGA最大,采用云南地区地震动衰减关系得到的PGA最小,采用川藏地区及青藏高原东北缘地震动衰减关系时居中;在同一地震动衰减关系下,采用自编空间分布函数计算得到的PGA普遍略大于采用第五代图空间分布函数时;在震级上限为8.5的潜在震源区及附近地区,潜在震源区空间分布函数震级分档对计算结果有显著影响。综合分析表明,采用自编Ⅱ型震级分档空间分布函数方案与川藏地区地震动衰减关系组合方案的计算结果最为理想。最后,采用该组合方案对青藏工程走廊50年超越概率10%的基岩场地PGA及一般场地PGA进行了区划。 相似文献
2.
—?The problem of accounting for local soil effect on earthquake ground motion is especially urgent when assessing seismic hazard – recent needs of earthquake engineering require local site effects to be included into hazard maps. However, most recent works do not consider the variety of soil conditions or are performed for generalized site categories, such as “hard rock,”“soft soil” or “alluvium.” A technique of seismic hazard calculations on the basis of the Fourier Amplitude Spectra recently developed by the authors allows us to create hazard maps involving the influence of local soil conditions using soil/bedrock spectral ratios. Probabilistic microzoning maps may be constructed showing macroseismic intensity, peak ground acceleration, response and design spectra for various return periods (probability of exceedance), that allow optimization of engineering decisions. An application of this approach is presented which focused on the probabilistic microzoning of the Tashkent City. 相似文献
3.
B. Pace D. Albarello P. Boncio M. Dolce P. Galli P. Messina L. Peruzza F. Sabetta T. San�� F. Visini 《Bulletin of Earthquake Engineering》2011,9(1):199-230
After the April 6th 2009 L’Aquila earthquake (M
w
6.3), where 306 people died and a further 60,000 were displaced, seismic microzoning investigations have been carried out
for towns affected by a macroseismic intensity equal to or greater than 7 MCS. Based upon seismotectonic data, historical
seismicity and strong motion records, we defined input spectra to be used in the numerical simulations of seismic microzoning
in four key municipalities, including the town of L’Aquila. We adopted two main approaches: uniform hazard response spectra
are obtained by a probabilistic seismic hazard assessment introducing some time-dependency for individual faults on the study
area; a deterministic design spectrum is computed from magnitude/distance pairs extracted by a stationary probabilistic analysis
of historical intensities. The uniform hazard spectrum of the present Italian building code represents the third, less restrictive,
response spectrum to be used for the numerical simulations in seismic microzoning. Strong motions recordings of the main shock
of the L’Aquila sequence enlighten the critical role played by both the local response and distances metric for sites located
above a seismogenic fault; however, these time-histories are compatible with the uncertainties of a deterministic utilization
of ground motion predictive equations. As recordings at very near field are rare, they cannot be neglected while defining
the seismic input. Disaggregation on the non-Possonian seismotectonic analysis and on the stationary site-intensity estimates
reach very similar results in magnitude-distance pairs identification; we interpret this convergence as a validation of the
geology-based model by historical observations. 相似文献
4.
本文基于对我国华北地区地震活动在时间和空间不均匀分布的认识,吸收了近20年来地震预测方面的科研成果,采用目前国际通用的地震危险性概率分析方法,通过对华北区划的试验,对地震区划的原则和方法提出了如下改进: 1.以地震带作为地震活动性参数的统计单元.引入地震活动趋势估计因素,评定表征地震活动水平的年平均发生率,以使区划结果同预测未来时间段地震活动水平相适应; 2.采用按震级挡次分配各潜在震源区的年平均发生率,可以合理地评估高震级地震的危险程度; 3.采用以震级挡次为条件概率的空间分布函数,刻画地震带内各潜在震源区之间发生相应震级挡次地震的相对危险程度,使区划结果更好地反映地震活动在时间和空间上不均匀性分布的特点; 4.在地震危险性分析计算中,引入了方向性函数项,使得分析模型更接近我国地震震源的实际情况. 相似文献
5.
盘锦、海城、营口地区是辽宁省内地震活动性最强、地震危险性最高的地区。该地区开展了大量重点工程地震安全性评价、区域性地震区划和地震小区划工作，但尚未开展基于场地条件的区域尺度地震危险性研究。独有的沉积特点使该地区场地条件较复杂，因此在地震危险性概率分析中考虑场地条件是必要的。本文基于新一代中国地震动参数区划图基本原理和技术原则，结合盘锦、海城、营口地区场地条件特征，采用基于地形坡度的方法对场地条件进行分类，确定场地地震动影响系数，给出该地区基于区域场地条件的地震危险性分布，相关研究结果可为地震风险评估和防震减灾规划提供参考。 相似文献
6.
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
7.
采用了分布式地震活动性模型. 该模型无需潜在震源区划分,同时简化了地震危险性概率分析方法. 根据破坏性地震目录建立了3个地震活动性模型,利用高斯光滑函数获得了华北区域内的a值分布特征,使用3种典型的衰减模型,分别计算了50年内超越概率10%, 5%和2%的地震动峰值加速度分布. 其分析结果显示了峰值加速度分布特征与我国第四代区划图大体一致,特定地震活动区（太原、 石家庄等地区）的峰值加速度略高于第四代区划图的结果,而这种峰值加速度分布特征与该地区较高的地震活动性特征是一致的. 概率危险性曲线结果表明,唐山、太原和北京等地区的潜在地震危险性比华北区域内其它城市高. 相似文献
8.
Jorge M. Gaspar-Escribano Manuel Navarro Belén Benito Antonio García-Jerez Francisco Vidal 《Bulletin of Earthquake Engineering》2010,8(6):1547-1567
An approach that relates results from a regional seismic hazard assessment study with local-scale site-effect characterizations
in an area of low-to-moderate seismic activity such as Andalusia (southern Spain), is presented. Results of a previous probabilistic
seismic hazard analysis of Andalusia on rock conditions are disaggregated to infer hazard controlling earthquakes for different
target motions. A collection of controlling magnitude-distance pairs and the corresponding site-specific response spectra
at main capital cities of the region are obtained. These spectra are first-order approximations to expected seismic actions
required in local earthquake risk assessments. In addition, results of independent, local-scale studies developed in Almeria
City (SE Andalusia) are used to derive an updated seismic zonation of the city. These include predominant soil period estimates
and shear-wave velocity profiles at different locations. If a local seismic risk assessment study or an earthquake-resistant
structural design is to be developed, it may be recommended the use of different seismic actions on sites characterized by
distinct response to seismic shaking (as derived from the seismic zonation). The seismic action related to worst-case scenarios
may be modeled through a hazard-consistent response spectrum, obtained by hazard disaggregation at the spectral acceleration
with period matching the prevailing resonant period of the target site or structure. 相似文献
9.
山东省场地类别分布及地震动峰值加速度区划调整 总被引：1，自引：1，他引：0
首先,本文搜集了山东省5220个建设工程场地的资料,引入"分布区"的概念,统计分析了山东省场地类别的区域分布并进行了分区。然后,根据《中国地震动参数区划图（GB18306-2015）》中的山东省地震动峰值加速度区划以及Ⅲ类场地调整系数,对山东省Ⅲ类场地分布区的地震动峰值加速度区划进行了调整,得到了考虑场地类别分区的山东省地震动峰值加速度区划图,增进了对山东省地震灾害风险空间分布的认识。结果表明,山东省场地类别分布与地貌分区有很强的相关性,Ⅰ-Ⅱ类场地分布区包括鲁中南山地丘陵区（西南部的山间平原地带除外）以及鲁东丘陵区,Ⅲ类场地分布区包括鲁西北-鲁西南平原区和鲁中南山地丘陵区西南部山间平原地带。Ⅰ-Ⅱ类场地分布区约占全省陆地面积的59.5%,Ⅰ-Ⅱ类场地分布区与Ⅲ类场地分布区的面积比例约为1.47。地震动峰值加速度区划图经过调整后,Ⅶ度及以上设防区域占全省陆地面积的比例由79%提高到90%,10个地级市的峰值加速度有提高。 相似文献
10.
L. Peruzza A. Rebez D. Slejko P. L. Bragato 《Soil Dynamics and Earthquake Engineering》2000,20(5-8):361-371
Probabilistic seismic hazard maps, in terms of spectral acceleration and uniform hazard response spectra at given sites, considering local soil conditions, represent a much more complete estimate of the seismic hazard than the traditional maps in terms of peak ground acceleration or macroseismic intensity. This is particularly true when the requests of urban planners and engineers have to be met. The present analysis shows how some hazard parameters, such as the effective peak acceleration and the spectrum intensity, can well synthesise the overall information available from traditional probabilistic studies, but also suggests that soil condition is a first-order ingredient for effective seismic hazard mapping at national level. Three Italian towns, damaged by the 1997 Umbria–Marche earthquake sequence, are considered as example to demonstrate that: (1) soil condition dependent uniform hazard spectra well approximate actual spectra recorded during some events of the seismic sequence; (2) for these localities, the design spectrum of the present Italian seismic code does not seem adequate.
These considerations have induced the Italian scientific community to propose an updating of the national seismic zonation on the basis of several hazard parameters, that are described in this paper. 相似文献
11.
In this paper, by means of the statistical analysis method of stochastic spatial point process, statistical analysis of spatial
distribution of earthquakes in the large northern region of China is made. Emphasis is on the test and analysis of the complete
spatial randomness, correlation of earthquake distribution in the different magnitude interval and random labeling. It is
shown by the analysis that the spatial distribution of earthquakes in the large northern region is “clustered”, the distributions
of earthquakes in different magnitude interval are positively correlated and can be modeled by a two-dimensional process.
The results obtained in the paper can be used for the establishment of a reasonable spatial distribution model and have some
application in the reasonable estimation of seismic hazard.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 129–135, 1993. 相似文献
12.
Research on the principle and methodology of seismic zonation 总被引：1，自引：0，他引：1
Based on the cognizance of the temporal-spatial inhomogeneity of seismicity in North China, adopting the results of earthquake prediction in the past two decades and the currently used methods of seismic hazard analysis, and after some zonation trials in North China, some improvements on the zonation principle and methodology were made:
- Seismic zones were taken as statistic units where seismicity parameters were obtained. Tendency analysis was introduced. Earthquake annual average occurrence rates were estimated corresponding to the seismicity level in the future period;
- Average annual earthquake occurrence rates for a given magnitude interval of a specific seismic zone were assigned to potential sources considering the relative risk level among these sources. Thus, the risk of great earthquakes can be estimated.
- The probabilistic spatial distribution function under the condition of magnitude interval was suggested to reflect the temporal and spatial inhomogeneity of seismicity.
- An orientation function in the seismic hazard analysis model was adopted, which reflects the real condition of earthquake foci in China.
13.
城市是人口密集、财富集中的区域,也是需要采取特别抗震设防措施的重点地区。地震小区划是精细划分城市抗震设防单元的重要技术途径,可以帮助摸清城市所面临的潜在地震灾害风险,并为城市规划和建设提供更加科学的抗震设防要求。1986—2022年6月,中国共完成城市地震小区划项目369个,地震小区划总面积22856.6km2,涉及61.3%的省会城市和直辖市、33%的设区的市和地(州、盟)驻地城市以及14.1%的县(市、区、旗)所在城市。本文利用文献调研和统计学方法,系统总结了中国城市地震小区划工作开展情况,分析存在的问题,并对今后推进地震小区划工作提出了建议。 相似文献
14.
本文选取华北地震区作为研究区域,尝试利用空间光滑活动模型进行地震危险性评估.首先对研究区域进行划分网格,依据地震构造和地震空间分布特征建立地震构造模型,确定构造区特征参数(b值、M0、Mu、断层方位角及M-L关系等).采用考虑了地震构造背景的椭圆光滑过程的地震活动参数模型,计算各网格点的地震发生率.并利用网格源的地震危险性概率评价方法,由不同输入地震目录通过综合加权得到该区域50年超越概率10％的加速度峰值区划结果.该方法充分体现了地震活动的空间非均一性,尤其适用于发震构造不甚清晰的中强地震可能造成的地震危险性,避免了常规潜在震源区的划分.且评价方法简单快捷,为地震区划以及重大工程地震安全性评价工作提供了新的技术方法. 相似文献
15.
16.
Earthquakes damage engineering structures near, relatively to the rupture's size, to the source. In this region, the fault's dynamics affect ground motion propagation differently from site to site, resulting in systematic spatial variability known as directivity. Although a number of researches recommend that records with directivity‐related velocity pulses should be explicitly taken into account when defining design seismic action on structures, probabilistic seismic hazard analysis (PSHA), in its standard version, seems inadequate for the scope. In the study, it is critically reviewed why, from the structural engineering point of view, hazard assessment should account for near‐source effects (i.e., pulse‐like ground motions), and how this can be carried out adjusting PSHA analytically via introduction of specific terms and empirically calibrated models. Disaggregation analysis and design scenarios for near‐source PSHA are also formulated. The analytical procedures are then applied to develop examples of hazard estimates for sites close to strike–slip or dip–slip faults and to address differences with respect to the ordinary case, that is, when pulse‐like effects are not explicitly accounted for. Significant increase of hazard for selected spectral ordinates is found in all investigated cases; increments depend on the fault‐site configuration. Moreover, to address design scenarios for seismic actions on structures, disaggregation results are also discussed, along with limitations of current design spectra to highlight the pulse‐like effects of structural interest. Finally, an attempt to overcome these, by means of disaggregation‐based scenarios specific for the pulse occurrence case, is presented. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
17.
To actually reflect the seismic temporal-spatial inhomogeneity of intra continental strong earthquakes of North China in seismic
hazard analysis, several seismological and geological characteristics have been selected and quantized to describe the seismicity
features in time and space of every magnitude interval with the thought of dividing the interesting magnitude range into several
intervals and using of spatial probability distribution function. A component analysis method with orthogonal transformation
is introduced to avoid the repeated use of the same element and the subjective effects in determining the annual earthquake
occurrence rates of earthquake. By passing synthetic fuzzy judgement on the nonintercorrelated new characteristics, the annual
occurrence rates of every magnitude interval of each potential source area are obtained associated with the adjustments of
earthquake reducing process after the occurrence ofM>7 quake. An intensity map of the Beijing-Tianjin-Zhangjiakou area is calculated as an example which shows a close coincidence
with the seismic temporal-spatial inhomogeneity of North China.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 496–504, 1991. 相似文献
18.
A methodology is proposed to determine design earthquakes for site-specific studies such as the siting of critical structures (power plants, waste disposals, large dams, etc.), strategic structures (fire stations, military commands, hospitals, etc.), or for seismic microzoning studies, matching the results of probabilistic seismic hazard analyses. This goal is achieved by calculating the source contribution to hazard and the magnitude–distance deaggregation, showing that, varying the selected frequency and the level of hazard, the reference earthquakes are changed as a result. A procedure is then adopted to minimize the residuals between the uniform hazard spectrum (target motion) and the design earthquake spectrum, to provide a specific earthquake scenario encompassing all the frequencies of the target motion. Finally, some considerations on the use and the influence exerted by ground motion uncertainty (σ) on hazard deaggregation are outlined. 相似文献
19.
目前我国针对陆域地区的建筑物和构筑物已建立了比较完备的抗震设计理论和技术体系,但对于海洋工程的抗震研究工作开展得不充分,尤其是海洋岛礁场地的地震反应分析尚属空白。伴随着近年来我国南海地区的迅速开发建设,有必要对南海岛礁的地震危险性分析和抗震设计展开研究。介绍南海岛礁场地的特殊工程地质条件和地震活动性特征,通过比较目前国内外常用的场地地震反应分析方法,针对岛礁这一特殊工程地质体,提出岛礁场地地震反应分析中需要考虑的四个显著因素,包括(1)南海岛礁体的特殊地形;(2)南海岛礁特殊的岩土工程材料;(3)海水-岛礁体动力相互作用;(4)南海地区海底输入地震动的确定,并探讨解决这些问题的思路。为分析地震作用下岛礁场地的稳定性、场地反应分析提供研究思路,同时为南海岛礁建设中的地震危险性分析提供参考。 相似文献
20.
Hazard-consistent response spectra in the Region of Murcia (Southeast Spain): comparison to earthquake-resistant provisions 总被引：1，自引：1，他引：0
Jorge M. Gaspar-Escribano Belén Benito Julián García-Mayordomo 《Bulletin of Earthquake Engineering》2008,6(2):179-196
Hazard-consistent ground-motion characterisations of three representative sites located in the Region of Murcia (southeast
Spain) are presented. This is the area where the last three damaging events in Spain occurred and there is a significant amount
of data for comparing them with seismic hazard estimates and earthquake-resistant provisions. Results of a probabilistic seismic
hazard analysis are used to derive uniform hazard spectra (UHS) for the 475-year return period, on rock and soil conditions.
Hazard deaggregation shows that the largest hazard contributions are due to small, local events for short-period target motions
and to moderate, more distant events for long-period target motions. For each target motion and site considered, the associated
specific response spectra (SRS) are obtained. It is shown that the combination of two SRS, for short- and long-period ground
motions respectively, provides a good approximation to the UHS at each site. The UHS are compared to design response spectra
contained in current Spanish and European seismic codes for the 475-year return period. For the three sites analysed, only
the Eurocode 8 (EC8) type 2 spectrum captures the basic shape of the UHS (and not the EC8 type 1, as could be expected a priori).
An alternative response spectrum, anchored at short- and long-period accelerations, is tested, providing a close match to
the UHS spectra at the three sites. Results underline the important contribution of the frequent, low-to-moderate earthquakes
that characterize the seismicity of this area to seismic hazard (at the 475-year return period). 相似文献