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1.
Intermediate-depth earthquakes in the Vrancea region occur in response to stress generation due to descending lithosphere
beneath the southeastern Carpathians. In this article, tectonic stress and seismicity are analyzed in the region on the basis
of a vast body of observations. We show a correlation between the location of intermediate-depth earthquakes and the predicted
localization of maximum shear stress in the lithosphere. A probabilistic seismic hazard assessment (PSHA) for the region is
presented in terms of various ground motion parameters on the utilization of Fourier amplitude spectra used in engineering
practice and risk assessment (peak ground acceleration, response spectra amplitude, and seismic intensity). We review the
PSHA carried out in the region, and present new PSHA results for the eastern and southern parts of Romania. Our seismic hazard
assessment is based on the information about the features of earthquake ground motion excitation, seismic wave propagation
(attenuation), and site effect in the region. Spectral models and characteristics of site-response on earthquake ground motions
are obtained from the regional ground motion data including several hundred records of small and large earthquakes. Results
of the probabilistic seismic hazard assessment are consistent with the features of observed earthquake effects in the southeastern
Carpathians and show that geological factors play an important part in the distribution of the earthquake ground motion parameters. 相似文献
2.
地震滑坡危险性概念和基于力学模型的评估方法探讨 总被引：1，自引：0，他引：1
在我国大陆地区运用基于力学模型的Newmark位移分析方法开展地震滑坡危险性定量评估,尚处在起步阶段.为了进一步明确地震滑坡危险性概念和改进推广基于力学模型的评估方法,首先阐明了狭义的地震滑坡危险性预测评估与震后反演评估的关系; 同时为了应对地震应急、震后重建及潜在地震条件下的不同评估需求,初步提出了广义的地震滑坡危险性评估框架.随后申述了基于Newmark位移分析的地震滑坡危险性评估方法的理论基础、方法分类及最新进展,并以汶川地震滑坡危险性快速评估为例,剖析了目前影响评估有效性的不确定性及空间数据质量等问题,指出了基于力学模型的地震滑坡危险性评估方法的改进方向.建议开展潜在地震及其诱发滑坡危险性的耦合评估,建立适用于我国大陆地区地震滑坡位移分析的经验模型,以便为国家层面的地震滑坡危险性区划服务. 相似文献
3.
Within the framework of the performance based earthquake engineering, site specific earthquake spectra for Van province has been obtained. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage data from geological studies and records from the instrumental period were compiled to make a seismic source characterization for the study region. The probabilistic seismic hazard curves were developed based on selected appropriate attenuation relationships, at rock sites, with a probability of exceedance 2, 10 and 50% in 50 yrs period. The obtained results are compared with the spectral responses proposed for seismic evaluation and retrofit of building structure in Turkish Earthquake Code (2007), section 7. The acceleration response spectrums obtained from probabilistic seismic hazard analysis are matched to adjust earthquake accelerograms recorded during the 2011 Van earthquakes by using SeismoMatch v2.0 software. The aim of this procedure is to obtain a set of reasonable earthquake input motions for the seismic evaluation of existing buildings. 相似文献
4.
The assessment of local site effects on seismic ground motions is of great importance in earthquake engineering practice.
Several destructive earthquakes in the past have demonstrated that the amplification of ground motion and associated damage
to structures due to local site conditions is a significant consideration in earthquake hazard analysis. A recent paper published
in this journal highlights the hazard posed by earthquakes in the megacity of Kolkata in India due to its seismic and geological
settings. The seismic hazard assessment study speculates that the deep alluvial deposit in the city may increase the seismic
hazard probably due to the amplification of the seismic energies. This paper focuses on the seismic response studies of the
various soil strata (i.e. for local subsurface conditions) obtained from various construction sites in the city for predicted
earthquake. It is very well recognized that site response studies (a part of seismic microhazard zonation for urban areas)
are the first step towards performance-based foundation design or seismic risk analysis and mitigation strategy. One of the
problems for carrying out site-specific study in Kolkata is the lack of recorded strong motion data in the city. Hence, this
paper outlines a methodology to carry out site-specific study, where no strong motion data or seismic data are available.
The methodology uses wavelet-based spectrum compatibility approach to generate synthetic earthquake motions and equivalent
linear method for seismic site response analysis. The Mega City of Kolkata has been considered to explain the methodology.
Seismic hazard zonation map by the Bureau of Indian Standards classifies the City of Kolkata as moderate seismic zone (Zone
III) with a zone factor 0.16. On the other hand, GSHAP(Global Seismic Hazard Assessment Program) map which is based on 10%
probability of exceedance in 50 years specifies a maximum peak ground acceleration (PGA) of 1.6 m/s2 (0.163 g) for this region. In the present study, the seismic response has been carried out based on GSHAP. The results of
the analysis indicate the amplification of ground motion in the range of 4.46–4.82 with the fundamental period ranging from
0.81 to 1.17 s. Furthermore, the maximum spectral accelerations vary in the range of 0.78–0.95 g. 相似文献
5.
Generally the seismic hazard of an area of interest is considered independent of time. However, its seismic risk or vulnerability, respectively, increases with the population and developing state of economy of the area. Therefore, many areas of moderate seismic hazard gain increasing importance with respect to seismic hazard and risk analysis. However, these areas mostly have a weak earthquake database, i.e., they are characterised by relative low seismicity and uncertain information concerning historical earthquakes. In a case study for Eastern Thuringia (Germany), acting as example for similar places in the world, seismic hazard is estimated using the probabilistic approach. Because of the lack of earthquakes occurring in the recent past, mainly historical earthquakes have to be used. But for these the actual earthquake sources or active faults, needed for the analysis, are imprecisely known. Therefore, the earthquake locations are represented by areal sources, a common practice. The definition of these sources is performed carefully, because their geometrical shape and size (apart from the earthquake occurrence model) influence the results significantly. Using analysis tools such as density maps of earthquake epicentres, seismic strain and energy release support this. Oversizing of areal sources leads to underestimation of seismic hazard and should therefore be avoided. Large location errors of historical earthquakes on the other hand are represented by several alternative areal sources with final superimposition of the different results. In a very similar way information known from macroseismic observations interpreted as source rather than as site effects are taken into account in order to achieve a seismic hazard assessment as realistic as possible. In very local cases the meaning of source effects exceeds those of site effects very likely. The influence of attenuation parameter variations on the result of estimated local seismic hazard is relatively low. Generally, the results obtained by the seismic hazard assessment coincide well with macroseismic observations from the thoroughly investigated largest earthquake in the region. 相似文献
6.
Ade Faisal Taksiah A. Majid Fauziah Ahmad Felix Tongkul Syafrina Mayang Sari 《Natural Hazards》2011,59(1):237-269
The seismic hazard assessment of a site that lies in the low seismic region affected by the future existence of a large dam
has been given less attention in many studies. Moreover, this condition is not addressed directly in the current seismic codes.
This paper explains the importance of such information in mitigating the seismic hazard properly. Ulu Padas Area in Northern
Borneo is used as an example for a case study of a site classified as a low seismic region. It is located close to the border
of Malaysia, Brunei Darussalam, and Indonesia and may have a large dam in the future as the region lies in hilly geography
with river flow. This study conducts probabilistic and deterministic seismic hazard analyses, and reservoir-triggered seismicity
of a site affected by the future existence of a large dam. The result shows that the spectrum acceleration of the maximum
design earthquake for the investigated site in the Ulu Padas Area in Northern Borneo is taken from the reservoir-triggered
seismicity earthquake at short periods and from the current condition at longer periods. 相似文献
7.
Kasım Armağan Korkmaz 《Environmental Earth Sciences》2010,61(3):467-476
A significant proportion of the urban areas in Turkey is subject to high seismic risk. An important step for seismic risk
mitigation is to define the hazard and damage after an earthquake. This paper proposes an integrated seismic hazard assessment
and disaster management processes for Turkey. The proposed methodology utilizes information technologies in its seismic assessment
component that provides fast results for assessment. First, image process methodology by using satellite images was implemented
in the seismic assessment process for fast evaluation right after an earthquake. Second, the seismic assessment process was
integrated with disaster management process. As a result, through integrated seismic hazard evaluation and disaster management
procedure, an effective, fast and dependable estimation of loss for Turkey was planned. 相似文献
8.
以穿越汶川震区的成兰铁路龙门山关键段为例, 探索提出了强震扰动背景下重大工程场区多尺度滑坡危险性评估方法。利用信息量模型反演评估了汶川地震诱发的同震滑坡空间分布特征, 以此为前提开展了区域和局地两种空间尺度的滑坡危险性预测评估。在区域廊带尺度上, 分别利用可能最大降雨量预测方法和信息量模型, 进行了日超越概率10%的最大降雨量时空分布预测及其诱发滑坡的危险性评估; 同时, 结合地震危险性区划成果, 开展了50年超越概率10%的基本地震动诱发滑坡的危险性评估。在局地场站尺度上, 利用基于崩塌运动过程模拟的Rockfall Analyst软件, 开展了柿子园大桥周边崩塌运动学特征(Runout)模拟和危险性评估。滑坡和崩塌危险性评估的结果分别为铁路规划选线和场站防护设计提供了不同尺度的地质安全依据。 相似文献
9.
Northeast India is one of the most highly seismically active regions in the world with more than seven earthquakes on an average per year of magnitude 5.0 and above. Reliable seismic hazard assessment could provide the necessary design inputs for earthquake resistant design of structures in this region. In this study, deterministic as well as probabilistic methods have been attempted for seismic hazard assessment of Tripura and Mizoram states at bedrock level condition. An updated earthquake catalogue was collected from various national and international seismological agencies for the period from 1731 to 2011. The homogenization, declustering and data completeness analysis of events have been carried out before hazard evaluation. Seismicity parameters have been estimated using G–R relationship for each source zone. Based on the seismicity, tectonic features and fault rupture mechanism, this region was divided into six major subzones. Region specific correlations were used for magnitude conversion for homogenization of earthquake size. Ground motion equations (Atkinson and Boore 2003; Gupta 2010) were validated with the observed PGA (peak ground acceleration) values before use in the hazard evaluation. In this study, the hazard is estimated using linear sources, identified in and around the study area. Results are presented in the form of PGA using both DSHA (deterministic seismic hazard analysis) and PSHA (probabilistic seismic hazard analysis) with 2 and 10% probability of exceedance in 50 years, and spectral acceleration (T = 0. 2 s, 1.0 s) for both the states (2% probability of exceedance in 50 years). The results are important to provide inputs for planning risk reduction strategies, for developing risk acceptance criteria and financial analysis for possible damages in the study area with a comprehensive analysis and higher resolution hazard mapping. 相似文献
10.
概率地震危险性评价系统开发 总被引：1，自引：0，他引：1
工程建设时必须对工程场地的地震危险性进行评价,并且对工程结构物要采取抗震设计。由于相关部门往往针对某一地区只提供一个地震设防加速度范围值或地震设防烈度值,而且某一地震烈度值所对应的加速度值的范围也很大,使得在实际应用中给具体工程安全、经济地选用合适的抗震设防加速度带来一定困难;为解决这个问题,本文以概率地震危险性评价理论为基础,开发了一套地震危险性评价系统。利用该评价系统根据相关地震活动性参数,可以方便、快速地计算出具体工程应该采用的抗震设防加速度值,从而解决了工程活动中安全、经济地选用抗震设防加速度值的问题。文中还针对潜在线源和潜在面源的处理难以在程序上实现这一难题,分别提出了一种精确求解和近似求解的算法。本文并以实例进行了评价计算,计算结果与中国地震局公布的数据符合较好,从而验证了开发的评价系统具有较好的可信度。 相似文献
11.
The objective of this study is to evaluate the seismic hazard at the Esfarayen-Bojnurd railway using the probabilistic seismic hazard assessment (PSHA) method. This method was carried out based on a recent data set to take into account the historic seismicity and updated instrumental seismicity. A homogenous earthquake catalogue was compiled and a proposed seismic sources model was presented. Attenuation equations that recently recommended by experts and developed based upon earthquake data obtained from tectonic environments similar to those in and around the studied area were weighted and used for assessment of seismic hazard in the frame of logic tree approach. Considering a grid of 1.2 × 1.2 km covering the study area, ground acceleration for every node was calculated. Hazard maps at bedrock conditions were produced for peak ground acceleration, in addition to return periods of 74, 475 and 2475 years. 相似文献
12.
基于简化 Newmark位移模型的区域地震滑坡危险性快速评估以汶川MS 8.0级地震为例 总被引：1，自引：0，他引：1
以汶川MS8.0级地震重灾区的11县市为例,初步提出了基于简化Newmark位移模型的地震滑坡危险性应急快速评估方法。利用汶川地震即时地震动参数、工程地质岩性经验分组及地形坡度数据,借助ArcGIS空间数据建模工具编制了地震滑坡危险性快速评估流程模块。计算了区域浅表层饱和岩土体斜坡的静态安全系数Fs、临界加速度ac,并借此分析了地震滑坡易发性。利用经验式获得了汶川地震Arias强度和区域滑坡位移DN分布,实现了汶川地震重灾区地震滑坡危险性的快速评估,为应急救灾决策提供了参考。通过对比评估结果和震后滑坡调查成果,可知数十处灾难性滑坡绝大部分位于-高危险区的龙门山主中央断裂带两侧约20km地带中,显示了评估方法的可靠性; 同时,分析指出了空间数据精度及更新不足导致局部评估结果欠佳的局限性,并提出了改进建议。 相似文献
13.
An earthquake is a natural phenomenon which is very frequent in Himalayan region in India. In southern peninsula India, the spatial occurrence of earthquake is irregular, whereas the northeastern, the north and the northwestern Himalayan parts of India are subjected to regular occurrences of earthquakes as they mark the boundary of the Eurasian and the Indian Plate. Hence, it is important to study and develop spatial model and information tool to understand the seismic phenomenon. The geoinformatic technique plays a significant role in the analysis of geodatabase to study the natural disaster and hazard assessment. The main aim of the present study is to develop geospatial model based on earthquake hazard assessment tool (EaHaAsTo) through integrated geological and geoinformatic techniques to better understand the earthquake occurrences zones. The spatial and non-spatial data were collected and integrated in a GIS to prepare geospatial databases. The thematic and quantitative databases were generated, and analysis was carried out to understand the seismic characteristics of the study area. The geospatial model was developed by integrating thematic databases and geospatial analyzed using weighted linear combination method. Finally, the GIS based on customized EaHaAsTo was developed to visualize the output of the model in qualitative and quantitative forms. 相似文献
14.
The hazard assessment of potential earthquake-induced landslides is an important aspect of the study of earthquake-induced landslides. In this study, we assessed the hazard of potential earthquake-induced landslides in Huaxian County with a new hazard assessment method. This method is based on probabilistic seismic hazard analysis and the Newmark cumulative displacement assessment model. The model considers a comprehensive suite of information, including the seismic activities and engineering geological conditions in the study area, and simulates the uncertainty of the intensity parameters of the engineering geological rock groups using the Monte Carlo method. Unlike previous assessment studies on ground motions with a given exceedance probability level, the hazard of earthquake-induced landslides obtained by the method presented in this study allows for the possibility of earthquake-induced landslides in different parts of the study area in the future. The assessment of the hazard of earthquake-induced landslides in this study showed good agreement with the historical distribution of earthquake-induced landslides. This indicates that the assessment properly reflects the macroscopic rules for the development of earthquake-induced landslides in the study area, and can provide a reference framework for the management of the risk of earthquake-induced landslides and land planning. 相似文献
15.
The Himalayas are one of very active seismic regions in the world where devastating earthquakes of 1803 Bihar–Nepal, 1897 Shillong, 1905 Kangra, 1934 Bihar–Nepal, 1950 Assam and 2011 Sikkim were reported. Several researchers highlighted central seismic gap based on the stress accumulation in central part of Himalaya and the non-occurrence of earthquake between 1905 Kangra and 1934 Bihar–Nepal. The region has potential of producing great seismic event in the near future. As a result of this seismic gap, all regions which fall adjacent to the active Himalayan region are under high possible seismic hazard due to future earthquakes in the Himalayan region. In this study, the study area of the Lucknow urban centre which lies within 350 km from the central seismic gap has been considered for detailed assessment of seismic hazard. The city of Lucknow also lies close to Lucknow–Faizabad fault having a seismic gap of 350 years. Considering the possible seismic gap in the Himalayan region and also the seismic gap in Lucknow–Faizabad fault, the seismic hazard of Lucknow has been studied based on deterministic and the probabilistic seismic hazard analysis. Results obtained show that the northern and western parts of Lucknow are found to have a peak ground acceleration of 0.11–0.13 g, which is 1.6- to 2.0-fold higher than the seismic hazard compared to the other parts of Lucknow. 相似文献
16.
Different approaches to seismic hazard assessment are compared. Each of them could be applied more or less successfully for territories which are stable in time and have a high level of seismic activity. A long-term seismic catalogue, not only including historical but also paleoearthquake data, is an essential requirement. But, in practice, such an ideal situation is very rare. Initial data is usually poor and short-term. Seismic hazard assessment could be more complicated for regions which are transient between relatively stable platforms and active mountain massifs. A new step in geoinformation technology for seismic hazard assessment based on a GEO computer environment is presented, its application is illustrated by the real case hazard evaluation for the territory of the Stavropol region, which is situated between the Russian platform and the Great Caucasus. The regional catalogue covers a time period of about 150 years. Though the region under consideration is not large, seismic activity is variable in space, from almost aseismic zones to rather active areas. GEO allows us to incorporate different techniques and all available information in the analysis, including those which are very difficult to formalize. The space distribution of the maximum expected earthquake magnitude is determined as a function of geological and geophysical data. An important feature of GEO is that it makes it possible to control the result of complicated algorithms through some relatively simple physical reasons. 相似文献
17.
Pathways to seismic hazard evaluation: Extreme and characteristic earthquakes in areas of low and high seismicity 总被引：4，自引：0，他引：4
Paul W. Burton 《Natural Hazards》1990,3(3):275-291
The general philosophy of seismic hazard evaluation described here is appropriate for selection of seismic input to regional earthquake engineering codes prior to detailed on-site inspections and geotechnical assessments. Some probabilistic seismic hazard methodologies which can be applied in areas of low and high seismicity, are briefly described to emphasise the main equations with specimen results. Three aspects of hazard assessment are explored by different pathways. These include the analysis of regional earthquake catalogues to obtain magnitude recurrence, particularly using Gumbel extreme value statistics. This is extended to assess ground shaking hazard which is usually sought by earthquake engineers. Thirdly, the concept of earthquake perceptibility is developed, leading to the identification of an earthquake magnitude or type which is characteristic of a region. This most perceptible earthquake is most likely to be felt at any site in a region and provides an earthquake selection criterion which can be used in aseismic design of noncritical structures. Because there are several methods of seismic hazard evaluation, the view is expressed that it is sensible for practical purposes to seek results from different methods or different pathways to the hazard evaluation.Paper presented at the Commission of the European Communities' School on Earthquake Hazard Evaluation, Athens, and at the 21st General Assembly of the European Seismological Commission, held in Sofia, 1988.Now at School of Environmental Sciences, University of East Anglia, University Plain, Norwich NR4 7TJ, U.K. 相似文献
18.
白龙江引水工程是我国拟建的一项重大战略工程,而代古寺水库是该工程的水源枢纽。代古寺水库及其周围地区(本文研究区)活动断层发育、大地震频发,故亟需开展可靠的地震危险性评估,为该研究区内的工程建设和运营保驾护航。由于传统评估方法物理依据不足,难以正确评估研究区的地震危险性,故本文采用了基于地震物理预测的地震危险性评估新方法。研究结果表明,该研究区位于海原地震区,未来100年内该研究区的地震危险性主要源于海原地震区的下一次MS8.5标志性地震。根据断层地震活动、发震潜力与展布特征,我们预判了该标志性地震的可能发震断层和震中位置;应用地震烈度衰减关系,考虑不同震中位置,分别计算了其产生的地震烈度。为确保“百年大计”的白龙江引水工程代古寺水库水资源枢纽安全,我们建议该研究区的抗震设防烈度不宜低于8度。 相似文献
19.
Assessment of seismic hazard and liquefaction potential of Gujarat based on probabilistic approaches
Gujarat is one of the fastest-growing states of India with high industrial activities coming up in major cities of the state. It is indispensable to analyse seismic hazard as the region is considered to be most seismically active in stable continental region of India. The Bhuj earthquake of 2001 has caused extensive damage in terms of causality and economic loss. In the present study, the seismic hazard of Gujarat evaluated using a probabilistic approach with the use of logic tree framework that minimizes the uncertainties in hazard assessment. The peak horizontal acceleration (PHA) and spectral acceleration (Sa) values were evaluated for 10 and 2?% probability of exceedance in 50?years. Two important geotechnical effects of earthquakes, site amplification and liquefaction, are also evaluated, considering site characterization based on site classes. The liquefaction return period for the entire state of Gujarat is evaluated using a performance-based approach. The maps of PHA and PGA values prepared in this study are very useful for seismic hazard mitigation of the region in future. 相似文献
20.
建筑物的地震安全性是城市规划和建设过程首先要回答的问题。我国城市地震安全性评价的方法理论多针对地上建筑物,而对地下空间的地震安全性研究较为薄弱,严重滞后于城市发展对地下空间的需求。活断层是诱发地震、导致建筑物破坏的的直接因素。考虑到空间关系上,地下空间与断层之间的交互关系为相交或相离。因此,本文将地下空间分为两类:与断层相交的地下空间称为跨断层地下空间,远离断层的地下空间称为远离断层地下空间。本文尝试将断裂带同震地表破裂、地震峰值加速度、地震烈度等地表地震安全性评价考量的要素与地下空间埋藏深度建立联系,并在此基础上总结基于震害统计的地下空间地震安全性评价方法。最后,本文选取地下空间利用需求较高的深圳和北京地区为实例进行介绍。 相似文献