共查询到20条相似文献，搜索用时 15 毫秒
1.
In this study, the effect of ground geology on the acceleration response spectra is studied at 32 sites in Gujarat, India. The sites are grouped into Proterozoic, Mesozoic, Tertiary and Quaternary. The normalized acceleration response spectra at 5% damping of 407 strong ground motions (horizontal and vertical components) recorded at these sites varying in magnitude from 3.0 to 5.7 are determined. The study shows that the shape of the acceleration response spectra is influenced by the regional geology and local site conditions. The peak of maximum horizontal spectral amplification is between 0.03 and 0.05 s in Proterozoic formations, 0.06 and 0.10 s in Mesozoic formations, 0.06 and 0.08 s in Tertiary and 0.12 s in Quaternary formations. The maximum vertical spectral acceleration is at 0.025 s in Proterozoic, 0.07 s in Mesozoic, 0.05 s in Tertiary and 0.10 s in Quaternary formations. The average acceleration amplification factor in all the geological formations is between 2.5 and 3.0 both in horizontal and vertical components. It has been observed that acceleration response spectra at sites having same geological formations are also influenced by local site conditions. The study shows that the acceleration response spectrum in the current Indian code applicable for the entire country underestimates the seismic forces at hard-rock sites and overestimates at soft-soil sites. Using recorded strong motion data with Mw ranging from 3.5 to 5.7, an attenuation relationship is developed at six periods to predict geometric mean of horizontal spectral amplitudes for rock and soil sites. The spectral amplitudes predicted with the attenuation relationship match well with the observed one within statistical limits for hypocentral distances less than 200 km. 相似文献
2.
D. Bindi F. Pacor L. Luzi R. Puglia M. Massa G. Ameri R. Paolucci 《Bulletin of Earthquake Engineering》2011,9(6):1899-1920
We present a set of ground motion prediction equations (GMPEs) derived for the geometrical mean of the horizontal components and the vertical, considering the latest release of the strong motion database for Italy. The regressions are performed over the magnitude range 4?C6.9 and considering distances up to 200?km. The equations are derived for peak ground acceleration (PGA), peak ground velocity (PGV) and 5%-damped spectral acceleration at periods between 0.04 and 2?s. The total standard deviation (sigma) varies between 0.34 and 0.38?log10 unit, confirming the large variability of ground shaking parameters when regional data sets containing small to moderate magnitude events (M?<?6) are used. The between-stations variability provides the largest values for periods shorter than 0.2?s while, for longer periods, the between-events and between-stations distributions of error provide similar contribution to the total variability. 相似文献
3.
本文以国内川滇甘陕地区263个有详细场地资料的强震台站获得的802组地震动加速度记录为基础,研究了该地区加速度峰值比的总体分布特征,分别探讨了震中距和震级对加速度峰值比的影响特征,按照水平反应谱的标定方法对竖向反应谱进行标定并对其进行了统计分析。统计分析结果显示:竖向与水平向加速度峰值比的概率分布总体服从极值Ⅱ型分布,加速度峰值比均值为0.6,加速度峰值比≤0.65的累积频率为64%;Ⅱ类场地的加速度峰值比随震中距增大而减小;大震近场的加速度峰值比基本上远高于0.65;最后本文给出了不同场地类别下竖向反应谱特征参数,并与水平向反应谱特征参数进行了比较。 相似文献
4.
Ali A. Nowroozi 《Pure and Applied Geophysics》2010,167(12):1459-1474
The active faults near Tehran are capable of producing Mw magnitudes of 6.62?C7.23; at epicentral distances of 25?km from the active faults, and Mw?=?7.23, the peak ground horizontal acceleration, PGH, is between 386 and 730?cm/s2 and peak ground vertical acceleration, PGV, is between 192 and 261?cm/s2; the historic earthquake of the fourth century BC, Mw?=?7.16 produced the highest estimated PGH acceleration in Tehran, between 254 and 479?cm/s2 and PGV acceleration between 127 and 173?cm/s2. Earthquakes from 1909 to 2008, within 300?km from Tehran, are used for calculation of magnitude frequency relation, and results are applied to estimate PGH and PGV accelerations as a function of magnitudes for a set of fixed epicentral distance and site conditions; also as a function of epicentral distances for a set of fixed magnitudes and site conditions. Poisson??s distribution is used for probability calculation of PGH and PGV accelerations for several exposure times, site conditions and epicentral distances; accelerations with very high probability, near 1, are presented. At an epicentral distance of 10?km and exposure time of 450?years, in the northern part of Tehran, close to Mosha and the Northern Tehran faults, PGH acceleration is 800?C420?cm/s2 and PGV is 400?C220?cm/s2 with high probability. At an epicentral distance of 25?km and 1,000?years exposure time, PGH is 610?C320?cm/s2 and PGV is 310?C160?cm/s2 with high probability, where larger values are for soft soil and smaller values are for hard rock. 相似文献
5.
选取分布在北川-映秀中央断裂两侧断层距120 km以内的40个强震动台站的记录,对汶川地震近断层地震动竖向和水平向加速度峰值、速度峰值、竖向和水平向加速度反应谱及谱比值进行了统计分析.研究表明:(1)地震动加速度峰值有显著的上盘效应,经验衰减模型的结果表明,在距地表破裂3~60 km的范围内,龙门山发震断层上盘一侧竖向与水平向的加速度峰值要比衰减模型得到的平均值大30%~40%.上盘的加速度峰值残差大部分是正值,而断层下盘残差大部分为负;水平地震动的东西分量幅值总体要大于南北分量,东西分量衰减相对较慢.(2)地震动长周期成分较弱,加速度反应谱值随周期增大而迅速减小,在周期1.0 s 时,即使在靠近中央断裂的最大加速度反应谱值也只有0.5 g;地震动加速度反应谱谱比值(竖向/水平向)沿龙门山断层周围的分布,在较长周期(T=0.2 s, 0.5 s, 1.0 s)与短周期(T=0.05 s, 0.1 s)有明显的不同.(3)近断层竖向地震动显著,地震动加速度峰值比在(竖向/水平向)可达1.4.在龙门山发震断层的上盘,地震动加速度峰值比整体上比下盘要大,竖向地震动尤为剧烈.部分近断层记录的地震动谱比值(竖向/水平向)在短周期(< 0.1 s)甚至超过1.5,统计分析还表明谱比值在短周期段(< 0.1 s)随断层距的增大而减小. 相似文献
6.
本文收集了从南北地震带川滇甘陕地区263个有详细场地资料的强震台站获得的802组强震动记录,按照场地、震级和震中距等因素统计分析了竖向与水平向加速度反应谱比的形状以及不同场地、震级和震中距下不同周期段内的谱比平均值,并与建筑抗震规范GB50011—2010规定的0.65进行了比较。结果表明:竖向与水平向加速度反应谱比受场地、震级和震中距等因素的影响; Ⅰ类和Ⅱ类场地在全周期段的谱比均值基本上大于0.65;无论何种分组情况谱比均值在0.1—1.0 s周期范围内基本低于定值0.65,周期大于1.0 s的谱比均值基本上远高于0.65。因此对于大部分抗震规范直接把竖向地震作用取为水平向地震作用的0.65倍,有待商榷。本文建议根据水平向反应谱的标定方式来确定现有竖向强震动记录的竖向地震作用。 相似文献
7.
Recent studies have shown that the vertical component of ground motion can be quite destructive on a variety of structural systems. Development of response spectrum for design of buildings subjected to vertical component of earthquake needs ground motion prediction equations (GMPEs). The existing GMPEs for northern Iranian plateau are proposed for the horizontal component of earthquake, and there is not any specified GMPE for the vertical component of earthquake in this region. Determination of GMPEs is mostly based on regression analyses on earthquake parameters such as magnitude, site class, distance, and spectral amplitudes. In this study, 325 three-component records of 55 earthquakes with magnitude ranging from M w 4.1 to M w 7.3 are used for estimation on the regression coefficients. Records with distances less than 300 km are selected for analyses in the database. The regression analyses on earthquake parameters results in determination of GMPEs for peak ground acceleration and spectral acceleration for both horizontal and vertical components of the ground motion. The correlation between the models for vertical and horizontal GMPEs is studied in details. These models are later compared with some other available GMPEs. According to the result of this investigation, the proposed GMPEs are in agreement with the other relationships that were developed based on the local and regional data. 相似文献
8.
According to the epicenter distance and the site classification, the 404 groups of earthquake recordings of the main shock of the Chi-Chi, Taiwan China earthquake in 1999 are catalogued. Based on these data, we analyze the statistical features of duration, PGA, envelopes and the response spectra ratio of the horizontal and vertical components of the acceleration recordings. The results of these analyses show that the effect of site classification on the acceleration of various components is obvious; furthermore, fault direction also has certain effects on the characteristics of the horizontal components of ground motion. The detailed research results are as follows： （ 1 ） the duration of the horizontal components of acceleration records increases with the softening of the site; （2） the direction of fault slip has some effects on PGA＇s attenuation features; （3） the average envelopes of acceleration records at different distances and site dames are basically single peak functions of time and the envelopes of horizontal and vertical components of ground motion are obviously different; （4） with the same epicenter distance, EW/NS response spectrum ratios tend to approximate 1.0 as the site becomes softer and the period shorter. V/H response spectrum ratios in short periods （〈 0. 1s） increase with the softening of site, however, V/H ratios within the long-period range （ 〉 characteristic period） decrease with the softening of the site, and the decrease of V/EW ratio speeds up relatively. 相似文献
9.
Over 700 accelerograms recorded from 12 earthquakes in northeast Taiwan have been analysed for investigating the behaviour of the vertical and horizontal peak and spectral ground motion in the near-source region. Pseudo-relative spectral velocities (PSV), at 5 per cent critical damping for 23 frequencies in the range of engineering interest have been subjected to non-linear regression procedures in terms of magnitude and hypocentral distance. Predicted response spectra for several discrete distances and magnitudes are presented. The results show that the shape of response spectra for both vertical and horizontal components of ground motion is magnitude- as well as distance-dependent. The 2/3 ratio of vertical to horizontal ground motion, commonly used in engineering applications, appears unconservative in the very near field for high frequency ground motion. However, it falls below 1/2 at distances greater than 50 km. The same ratio for peak ground velocity (PGV) and peak ground displacement (PGD) tends to increase with distance—the latter at a faster rate. 相似文献
10.
Attenuations of the vertical and horizontal response spectra of the 17 October 1989 Loma Prieta, California, earthquake are developed through analyses of the ground motion at 53 sites within a 100 km radius of the source. The analyses are performed on the spectral ordinates for 16 incremental periods ranging from 0.05 to 2.0 sec. The response spectra are modelled empirically for two different site conditions characterized by rock and stiff-soil geologies. Data analysis is performed by the application of a non-linear multivariate regression procedure allowing for distance and site factor as independent variables. Variation of the vertical-to-horizontal (V/H) spectral ratios with wave frequency and distance shows the same behaviour as observed previously in the widely separated geographic regions of northeastern Taiwan and east-central Iran. The predicted ratios at sites underlain by stiff soil are generally higher than the commonly used value of 2/3 at high frequencies ( > 5 Hz) in the near-source region (R < 30 km), but reduce to 1/2 or less at longer periods and farther distances. This behaviour is also observed at rock sites; however, it is somewhat less pronounced. With a faster attenuation of spectral ordinates at higher frequencies, the shape of the response spectrum is found to change with distance. As expected, the spectral attenuation with distance is generally higher for the vertical spectrum than for the horizontal spectrum. The difference is particularly significant at the higher-frequency end of spectrum. Site amplification factors for stiff soil with respect to rock geology varies between 1.17 and 1.72 for horizontal spectrum and 1.01 and 1.81 for vertical spectrum. Spectral amplifications at four sites underlain by soft soil and artificial fill, are also evaluated. This is done by a comparison of the observed spectra with those predicted for rock geology at corresponding distances. As expected, the resulting amplification factors at soft-soil sites show significant increase relative to those at sites underlain by rock. 相似文献
11.
以反应谱和功率谱密度函数表征的强震运动的统计特性 总被引：1，自引：0，他引：1
文中利用我国海城和唐山地震１９０条强震记录和美国西部１３８条强震记录研究了以反应谱和功率谱密度函数表征的强震运动的统计特性。反应谱用最大地面加速度归一化，即表为谱放大系数，功率谱密度函数用金井清谱描述。文中研究了参数的统计值和依赖性，以及谱放大系数和金井清谱参数与场地条件、震源和震中距等之间的相关性，分析比较了中美两国强震运动谱的统计特性，并对我国地震工程应用的强震运动谱的统计参数值的选取提出了建议。 相似文献
12.
Near-field horizontal and vertical earthquake ground motions 总被引：8，自引：0，他引：8
Strong-motion attenuation relationships are presented for peak ground acceleration, spectral acceleration, energy density, maximum absolute input energy for horizontal and vertical directions and for the ratio of vertical to horizontal of these ground motion parameters. These equations were derived using a worldwide dataset of 186 strong-motion records recorded with 15 km of the surface projection of earthquakes between Ms=5.8 and 7.8. The effect of local site conditions and focal mechanism is included in some of these equations. 相似文献
13.
The 2008 MS8 Wenchuan earthquake occurs on a high angle listric thrust fault. It is the first time that the near and far field strong ground motion was observed for such special type thrust earthquake. This paper jointly interprets the distribution of peak acceleration of ground motion data with seismogenic structure and slip propagating process to investigate how high angle listric thrust fault controls the pattern of strong ground motion. We found that the distribution of peak acceleration of strong ground motion during the Wenchuan earthquake has four distinctive features: 1)The peak acceleration of ground motion inside the Longmenshan fault zone is large, that is, nearly twice as strong as that outside the fault zone; 2)This earthquake produces significant vertical ground motion, prevailing against horizontal components in the near field; 3)The far field records show that the peak acceleration is generally higher and attenuates slower versus station-fault distance in the hanging wall. It is doubtful that the attenuation of horizontal components also has the hanging wall effect since no evidence yet proving that the unexpected high value at long distance need be omitted; 4)As to the attenuation in directions parallel to the source fault(Yingxiu-Beichuan Fault), the far field records also exhibit azimuthal heterogeneity that the peak acceleration of horizontal components decreases slower in the north-northeastern direction in which the co-seismic slip propagates than that in the backward way. However, the attenuation of vertical component displays very weak heterogeneity of this kind. Synthetically considered with shallow dislocation, high dip angle, and prevailing vertical deformation during co-seismic process of the Wenchuan earthquake, our near and far field ground motion records reflect the truth that the magnitude of ground motion is principally determined by slip type of earthquake and actual distance between the slipping source patches and stations. As a further interpretation, the uniqueness of high angle listric thrust results in that the ground motion effects of the Wenchuan earthquake are similar to that due to a common thrust earthquake in some components while differ in the others. 相似文献
14.
当前,合理确定地震动峰值加速度与反应谱特征周期是工程场地地震动参数确定工作的主要内容。本文以北京地区典型中硬场地为研究对象,分析场地条件对不同周期地震动反应谱值的影响。首先,计算不同震级、震中距条件下的基岩地震动加速度反应谱,合成基岩输入地震动时程;再利用110个工程场地的钻孔资料进行土层地震反应计算,分析中硬场地条件对不同输入环境下的地震动加速度反应谱值的放大效应。结果表明,中硬场地对高、中频震动放大效应明显,尤其是对0.2-0.5s周期段地震动加速度反应谱值的放大倍数大多在1.3以上;场地覆盖层厚度变化对不同频段地震动加速度反应谱值的放大倍数所产生的影响是不同的,与场地自振周期的相关性很强;在不同的地震动输入环境下,中硬场地对不同频段地震动加速度反应谱的影响是不同的,这一结论对实际的抗震设防工作具有一定参考价值。 相似文献
15.
The city of Adapazarı — located in the Marmara Region of northwest Turkey — is situated on a deep sedimentary basin and was
the city most heavily damaged by the strong ground motion of the 17 August 1999 Kocaeli earthquake (moment magnitude Mw = 7.4). This study determines site amplifications of the attenuation relationships for shallow earthquakes in the Adapazarı
basin by using the previous ground motion prediction equations (GMPEs) and the traditional spectral ratio method. The site
amplifications are determined empirically by averaging the residuals between the observed and predicted peak ground acceleration
(PGA) and spectral acceleration (SA) values for various periods. Residuals are significantly correlated with the known characteristics
of geological units. A new attenuation model has also been developed for 5% damped spectral acceleration to determine the
dependence of strong ground motions on frequency. 相似文献
16.
One approach to model the high-frequency attenuation of spectral amplitudes of S-waves is to express the observed exponential decay in terms of Kappa (κ) factor [1]. Kappa is a significant parameter used for identifying the high-frequency attenuation behavior of ground motions as well as one of the key parameters for stochastic strong ground motion simulation method. As of now, there is not a systematic investigation of the Kappa parameter based on the recently-compiled Turkish ground motions. In this study, we examine a strong ground motion dataset from Northwestern Turkey with varying source properties, site classes and epicentral distances. We manually compute κ from the S-wave portion of each record and study both horizontal and vertical kappa values. We use traditional regression techniques to describe the (potential) relationships between kappa and selected independent variables such as the site class, distance from the source or magnitude of the event. A linear effect of magnitude on kappa is not found statistically significant for the database studied herein. We express the initial findings of a regional κ model for Northwestern Turkey as a function of site class and epicentral distances. Single station analyses at selected sites confirm the regional model. Finally, we present stochastic strong motion simulations of past events in the region using the proposed kappa model. Regardless of the magnitude, source-to-site distance and local site conditions at the stations, the high-frequency spectral decay is simulated effectively at all stations considered. 相似文献
17.
为了研究2021年5月22日玛多MS 7.4地震地震动特征,收集16个强震台的峰值加速度和其中9个台的强震波形数据,利用峰值加速度衰减及反应谱等分析玛多MS 7.4地震强震动特征。结果表明,多数台站的PGA值都随震中距的增大而平稳下降,PGA的衰减特征与青藏区衰减关系间有较好的一致性;土层台与基岩台的加速度反应谱明显不同,震中距越小,短周期高频成分越多,衰减越快,震中距越大,长周期高频成分越少,衰减越慢;加速度反应谱的水平向与竖向比值曲线在4 s内呈现两峰一谷的现象,初步认为,距发震断层较近的野马滩1号大桥所受到的破坏及水泥路面的明显错断受水平向地震动作用的影响更大。 相似文献
18.
Earthquake Researeh in Ch一na461 .METHODLet R be some value measured or estimated as a sequenee ina’‘Past”time interval(一丁,O)(I)万‘月,=(RI,…,R。),R,之R。,R=nlaX l二f匕11(RI,…,R,,) Values(l)eould have an arbitrary Physieal nature.BelowweshalleonsiderEq.(l)asearthquakemagnitudes in a given seismic aetive region or logarithms of seismie Peak ground aeeelerations at习given site.Ro isa而nimum eutoff value;it 15 defined by Possibilities of registration systems or wasehosen as the … 相似文献
19.
竖向与水平向地震动加速度反应谱比特性分析 总被引：2，自引：0，他引：2
本文采用全球范围128次地震的3235组三分量强地面运动记录,分析了其加速度竖向分量反应谱与水平分量反应谱的比值(V/H)的总体特征,研究了V/H随震级、震中距、局部场地条件和震源机制的变化关系。研究结果表明:(1)场地越硬,长周期段V/H越大,短周期段则相反;(2)震级越大,长周期段V/H越大,短周期段变化不明显;(3)短周期段V/H随震中距增大而减小;(4)对于大震(M7),长周期段V/H随震中距增大而减小;而对于中强震(M7),比值在近场(R60km)随震中距增加而增大,在远场则随震中距增加而减小;(5)V/H与震源机制也有一定的关系。 相似文献
20.
A large and uniform dataset is used to find equations for the prediction of absolute spectral acceleration ordinates in Europe and adjacent areas, in terms of magnitude, source-distance and site geology. The dataset used is shown to be representative of European strong motion in terms of the attenuation of peak ground acceleration. The equations are recommended for use in the range of magnitudes from MS 4⋅0 to 7⋅5 and for source-distances of up to 200 km. 相似文献