武汉地区地震效应影响研究

虽然武汉市地震影响及地震危险性的水平较低 ,强震也不是武汉市工程地质环境的主要问题 ,但在城市生命线工程和高层超高层建筑方面必须考虑单体抗震设防。而且 ,随着武汉市城市建设的不断发展 ,地震效应影响逐渐成为武汉市工程地质环境评价的一个重要因子。文章在分析了武汉地区地震动衰减规律 ,进行了地震危险性评价 ,深入研究了各土层动力参数性质的基础上 ,指出武汉地区地震地面破坏主要存在砂土液化和软土震陷两种型式及各自可能的空间分布.     

福建省城市活断层探测与地震危险性评价(综述)

本文由简要介绍国内外城市活断层的地震危害、城市活断层的研究现状和立项背景依据来说明福建省城市活断层探测与地震危险性评价工程项目来源 ,阐述了工程目标及其意义 ,叙述了工程的目标区、目标靶与技术方案等主要内容 ,介绍了工程实施的主要经验与存在问题 ,对目前取得的初步成果作了小结。     

城市烈度小区划工作的原则和方法

根据唐山地震对城市造成破坏情况的严重教训,城市有必要进行地震烈度小区划,它是城市进行抗震和城市远景规划的基础资料,及工程抗震设计的依据。     

工程地震勘探的科技进展

我国工程地震勘探已经历了一个较长的发展时期。80年代初,随着信号增强型浅层地震仪的出现,我国的工程地震科技取得了显著进展。浅层横波反射、城市工程勘察以及农药中的浅层地震测量技术已先后开发并得到应用,开始在我国一些重大工程项目中发挥积极作用。     

基于基岩裂缝分布的地震影响场分析

地震影响系数是地震安全评价的一个重要参数,由于受地下岩体条件影响,地震影响系数的确定在很大程度上具有不确定性,传统方法得到的地震影响场难以满足城市和重大工程抗震的要求,因此,地震影响场的不确定性校正是城市和工程抗震的一个必要环节。通过对地下岩体裂缝分布的数值模拟,得到基岩裂缝和地下能量等指标的分布。进而应用人工神经网络方法,确定基岩裂缝、能量、位移等指标的分布与地震影响系数之间的关系,探讨基岩条件对地震影响系数的影响,得到地震影响系数计算模型。计算了唐山市地震影响场,分析了计算结果,并对城市规划和工程建设提出了几点建议。     

城市震灾特点与江西省城镇抗震防灾工作中的地震问题

本文根据历史地震记载，现代地震台网记录资料和近年来的地震活动，工程地震和地震地质方面的研究成果，简述了城市地震灾害的特点；介绍了江西省境内城镇震灾概况和省境内地震活动的基本特征；提出了我省城市城镇抗震防灾工作中应注意的几个地震问题，即城市地区地震预测的基础研究，基岩山区的山崩，滑坡，沿江（河，湖）地区沉陷，砂土液化和水库下游城市的次生灾害等。     

与地震相关的西安地裂事件的全过程研究

运用历史分析方法,通过物探、热释光测年、古建筑地震地裂反应分析等,探讨了新生代以来与地震相关的西安地裂事件全过程,初步建立了与地震相关的西安地裂事件历程,并按地质历史、地震记载历史、现代三个阶段讨论了地裂灾害特征。并结合地裂场地地震动力效应研究,对未来 5 0年内与地震相关的地裂危险进行了预测。本文成果不仅可指导西安城市建设规划,而且为地裂灾害工程抗防提供了依据。     

煤炭科学研究总院西安研究院地震勘探工程与技术

煤炭科学研究总院西安研究院拥有一支人员素质高、仪器设备精良的地震勘探队伍,多年来承担了大量的二维,三维地震勘探工程,勘探区由第三纪地震、中生代地层到古生代地层;勘探领域从煤矿采区到公路,城市活断层等工程勘察。     

与城市地下生命线工程有关的双层地质结构中的几个问题

近代城市地下生命线工程要求对埋藏基岩中的活动断裂作出工程评价,以判断其是否有出现地表破裂的可能。 本文提出了对研究活动断裂的3项内容,即:“活动断裂的活动时间下限、地震复发周期及活动断裂的活动速率;对不同的断裂活动机制,即蠕动和粘滑,从覆盖层厚薄两种情况分析了对地基所产生的影响。 作者通过超声地震模型实验对覆盖层横向非均一性影响地下生命线工程的特点进行了研究,结果表明,横向非均一的覆盖层在地震过程中对地下生命线工程影响显著,不可忽视。     

江苏省镇江市抗震防灾规划编制完成

镇江市为江苏省重要的内河港口、历史文化名城和风景游览城市.镇东历史上曾多次遭受过地震袭击.早在公元320年《晋书》上就有“丹徒有地震”的记载(镇江原为丹徒县).镇江市地处活动较强的茅山断裂带边缘,历史上该断裂带曾发生过9次中强地震,其中1913年、1930年曾在镇江发生过5.5和5.0级地震,未来仍存在发生中强地震的可能性.因此,编制镇江市抗震防灾规划,减轻地震时城市的灾害损失及人员伤亡不仅必要而且是十分紧迫的.规划包括总则、地震危险性分析、抗震设防区划、地震灾害预测、土地利用规划、旧城改造及现有工程抗震加固规划、城市生命线工程的抗震防灾规划、地震应急救灾规划、震后恢复重建规划.     

Seismic risk in the city of Al Hoceima (north of Morocco) using the vulnerability index method,applied in Risk-UE project

Al Hoceima is one of the most seismic active regions in north of Morocco. It is demonstrated by the large seismic episodes reported in seismic catalogs and research studies. However, seismic risk is relatively high due to vulnerable buildings that are either old or don’t respect seismic standards. Our aim is to present a study about seismic risk and seismic scenarios for the city of Al Hoceima. The seismic vulnerability of the existing residential buildings was evaluated using the vulnerability index method (Risk-UE). It was chosen to be adapted and applied to the Moroccan constructions for its practicality and simple methodology. A visual inspection of 1102 buildings was carried out to assess the vulnerability factors. As for seismic hazard, it was evaluated in terms of macroseismic intensity for two scenarios (a deterministic and probabilistic scenario). The maps of seismic risk are represented by direct damage on buildings, damage to population and economic cost. According to the results, the main vulnerability index of the city is equal to 0.49 and the seismic risk is estimated as Slight (main damage grade equal to 0.9 for the deterministic scenario and 0.7 for the probabilistic scenario). However, Moderate to heavy damage is expected in areas located in the newer extensions, in both the east and west of the city. Important economic losses and damage to the population are expected in these areas as well. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategies in Al Hoceima.     

Spatial Distribution of Shear Wave Velocity for Late Quaternary Alluvial Soil of Kanpur City,Northern India

Empirical correlation between standard penetration resistance (SPT-N) and shear wave velocity measured by seismic downhole techniques are prepared of the alluvial soil of quaternary age for the Kanpur city. The Kanpur city is having seismic threat from Himalaya and it falls in seismic zone III according to seismic zones of India. Standard penetration test as well seismic downhole test has been carried out up to 30 m at twelve different locations of Kanpur city. The measured SPT-N values and shear wave velocity values are used to develop empirical correlation between SPT-N and shear wave velocity. The proposed correlations have been compared with the existing regression equations by various other investigators. It is found that the proposed correlation exhibit good performance (10 % error bar). Also the measured shear wave velocity has been used to prepare spatially distributed contour map of 50, 75 and 100 m/s using ArcGIS-9 software. It is observed that the shear wave velocity values for the northern part of Kanpur city vary from 125 to 825 m/s. In southern part, it is varying from 125 to 500 m/s where as in the central part of the city the shear wave velocity varies from 125 to 375 m/s. The eastern part of the city also shows some variation in shear wave velocity which ranges from 250 to 625 m/s. The western part of the city shows the variation of shear wave velocity from ≤125 to 500 m/s. The soil type of the study area are classified as per NEHRP and new Italian O.P.M.C classification system as B, C and D type soil with having site period of 0.1–0.9 s and Poisson’s ratio varying from 0.1 to 0.4.     

高分辨率城市活断层地震资料处理技术

高分辨率地震方法在城市活断层探测中,已成为一种不可缺少的方法技术。在活断层探测中,地震方法不但能确定断层的产状,而且还能确定断层的上断点。由于大多数地震资料都是在干扰背景较强的情况下取得的,高分辨率城市活断层中,地震资料处理的关键是在不降低地震记录分辨率的前提下,提高地震记录的信噪比。一般来说,提高地震记录的分辨率和信噪比是相互矛盾的。如何解决这一对矛盾,这里结合目前正在开展的城市活断层探测课题,进行了比较深入的研究,并取得了较好的处理效果。     

多层次多尺度的区域性震害预测模式

地震应急反应能力和灾害救援组织的效能是评价一个地区防震减灾水平的重要尺度。为了提高地震应急救援工作的能力 ,福建省地震局震害预测项目组采用多层次、多空间尺度的城乡震害预测技术途径和系统研究原则 ,以适应不同层次的地震应急、救援决策、组织指挥工作的需要。     

Spatial variation of probabilistic seismic hazard for Mumbai and surrounding region

Mumbai city, the economical capital of India, is located on the west coast of stable intra-plate continental region of Peninsular India which has an experience of significant historical earthquakes in the past. The city stood as the fourth most populous city in the world. Recent seismo-tectonic studies of this city highlighted the presence of active West coast fault and Chiplun fault beneath the Deccan basalt. In the present study, spatial variability of probabilistic seismic hazard for Mumbai region (latitudes of 18.85–19.35°N and longitudes of 72.80–73.15°E at a grid spacing of 0.05°) which includes Mumbai city, Suburban, part of Thane district and Navi Mumbai, in terms of ground motion parameters; peak horizontal acceleration and spectral acceleration at 1.0-s period for 2 and 10 % probability of exceedance in 50 years are generated. The epistemic uncertainty in hazard estimation is accounted by employing seven different ground motion prediction equations developed for worldwide shallow crustal intra-plate environments. Further, the seismic hazard results are deaggregated for Mumbai (latitude 18.94°N, longitude 72.84°E) to understand the relative contributions of earthquake sources in terms of magnitude and distance. The generated hazard maps are compared with the zoning specified by Indian seismic code (IS1893: Part 1 in Indian standard criteria for earthquake-resistant design of structures, Part 1—General provisions and buildings. Bureau of Indian Standards, New Delhi, India, 2002) for rocky site. Present results show an underestimation of potential seismic hazard in the entire study region by non-probabilistic zoning prescribed by IS1893: Part 1 with significantly higher seismic hazard values in the southern part of Navi Mumbai.     

Assessment of seismic risk scenarios for Bucharest,Romania

In this paper, seismic risk scenarios for Bucharest, the capital city of Romania, are proposed and assessed. Bucharest has one of the highest seismic risk levels in Europe, and this is due to a combination of relatively high seismic hazard and a building stock built mainly before the devastating Vrancea 1977 earthquake. In this study, the seismic risk of Bucharest is assessed using the most recent information regarding the characteristics of the residential building stock. The ground motion amplitudes are evaluated starting from random fields obtained by coupling a ground motion model derived for the Vrancea intermediate-depth seismic source with a spatial correlation model. The seismic risk evaluation method applied in this study is based on the well-known macroseismic method. For several structural typologies, the vulnerability parameters are evaluated based on a damage survey performed on 18,000 buildings in Bucharest after the March 1977 earthquake. Subsequently, the risk metrics are compared with those from other studies in the literature that apply a different risk assessment methodology in order to gain a better view of the uncertainties associated with a seismic risk study at city level. Finally, the impact of several Vrancea intermediate-depth earthquake scenarios is evaluated and the results show that the earthquake which has the closest epicenter to Bucharest appears to be the most damaging.

     

Attenuation laws and seismic hazard assessment

In the present study, the seismic hazard in the city of Patras, central Greece, is estimated. The computations are based on a slightly modified version of the method proposed by Cornell, allowing the introduction of individual attenuation laws for each seismic source. The obtained results emphasize the dependence of hazard on attenuation and the importance of the use of local attenuation laws in seismic hazard assessment.     

Assessment of seismic risk scenarios for Bucharest,Romania

In this paper, seismic risk scenarios for Bucharest, the capital city of Romania, are proposed and assessed. Bucharest has one of the highest seismic risk levels in Europe, and this is due to a combination of relatively high seismic hazard and a building stock built mainly before the devastating Vrancea 1977 earthquake. In this study, the seismic risk of Bucharest is assessed using the most recent information regarding the characteristics of the residential building stock. The ground motion amplitudes are evaluated starting from random fields obtained by coupling a ground motion model derived for the Vrancea intermediate-depth seismic source with a spatial correlation model. The seismic risk evaluation method applied in this study is based on the well-known macroseismic method. For several structural typologies, the vulnerability parameters are evaluated based on a damage survey performed on 18,000 buildings in Bucharest after the March 1977 earthquake. Subsequently, the risk metrics are compared with those from other studies in the literature that apply a different risk assessment methodology in order to gain a better view of the uncertainties associated with a seismic risk study at city level. Finally, the impact of several Vrancea intermediate-depth earthquake scenarios is evaluated and the results show that the earthquake which has the closest epicenter to Bucharest appears to be the most damaging.     

Site-specific earthquake response study for hazard assessment in Kolkata city,India

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.     

晋江市地震地质灾害评价与分区

本文收集了晋江市大量的工程地质勘察资料 ,针对晋江市区场地工程地质条件 ,从地震地质背景、历史震害的影响出发 ,依照相应规范和地质类比等方法 ,通过对晋江市区地震砂土液化、软土震陷、地震边坡效应、地震断层破坏效应的评判 ,结合地层、地形地貌分布情况 ,进行震害效应分区。