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1.
Observations from many recent strong motion events have shown the importance of local soil conditions and non-linear soil behaviour on the seismic ground response (site effects). As demonstrated by previous seismic microzoning studies (Lebrun et al.) [1]), as well as by at least three historical major earthquakes, Pointe-à-Pitre is prone to strong site effects, due to the particular geology of the area. In this paper, we present a comparison between the strong-motion data available from the stations operating on the swampy site of Pointe-à-Pitre airport and the ground motions derived from 1D non-linear finite element simulations.Results show that, for moderate to strong ground motions, 1D simulations reproduce the main characteristics of site response in terms of duration, energy distribution, amplitude and frequency content. It also shows the importance of very superficial soft layers as peat or saturated mud in low frequency site effects simulations. This point is important for further engineering studies since such very soft formations overlain by stiffer landfills are commonly expected in the Antilles context. Our work also shows that Anderson's criteria, used to quantify the goodness-of-fit of simulated ground motions to the observed ones, appear to be an interesting diagnostic tool for testing the quality of numerical simulations from an engineering point of view.  相似文献   

2.
On the selection of GMPEs for Vrancea subcrustal seismic source   总被引：2，自引：0，他引：2  
The Vrancea subcrustal seismic source is characterized by large magnitude ( $M_{W} \ge 7$ ) intermediate-depth earthquakes that occur two or three times during a century on average. In this study several procedures are used to grade four candidate ground motion prediction equations proposed for Vrancea source in the SHARE project. In the work of Delavaud et al. (J Seismol 16(3):451–473, 2012) four ground motion prediction models developed for subduction zones (Zhao et al. in Bull Seism Soc Am 96(3):898–913, 2006; Atkinson and Boore in Bull Seism Soc Am 93(4):1703–1729, 2003; Youngs et al. in Seism Res Lett 68(1):58–73, 1997; Lin and Lee in Bull Seism Soc Am 98(1):220–240, 2008) are suggested as suitable for Vrancea subcrustal seismic source. The paper presents the appropriateness analysis of the four suggested ground motion prediction equations done using a dataset of 109 triaxial accelerograms recorded during seven Vrancea seismic events with moment magnitude $M_{W}$ between 5.4 and 7.4, occurred in the past 35 years. The strong ground motions were recorded in Romania, as well as in Bulgaria, Republic of Moldova and Serbia. Based on the ground motion dataset several goodness-of-fit measures are used in order to quantify how well the selected models match with the recorded data. The compatibility of the four ground motion prediction models with respect to magnitude scaling and distance scaling implied by strong ground motion dataset is investigated as well. The analyses show that the Youngs et al. (Seism Res Lett 68(1):58–73, 1997) and Zhao et al. (Bull Seism Soc Am 96(3):898–913, 2006) ground motion prediction models have a better fit with the data and can be candidate models for Probabilistic Seismic Hazard Assessment.  相似文献   

3.
In this study, the broadband ground motions of the 2021 M7.4 Maduo earthquake were simulated to overcome the scarcity of ground motion recordings and the low resolution of macroseismic intensity map in sparsely populated high-altitude regions. The simulation was conducted with a hybrid methodology, combining a stochastic high-frequency simulation with a low-frequency ground motion simulation, from the regional 1-D velocity structure model and the Wang WM et al.(2022) source rupture model,respect...  相似文献   

4.
This paper evaluates possible directional effects from strong ground motions recorded during the last four significant subcrustal earthquakes produced in the Vrancea seismic zone(Romania) in August 1986(M_w=7.1),May 1990(M_w=6.9 and 6.4) and October 2004(M_w=6.0).Several measures of the horizontal component of the ground motion given in the literature(Boore et al.,2006;Boore,2010) are computed and are related to the geometric mean of the as-recorded horizontal components.ANOVA method is applied in order to quantify the influence of the earthquake magnitude and of the soil class on some strong ground motion parameters(e.g.Arias intensity,PGV/PGA,or mean period T_M).The study of the directional effects is performed using the distribution of I_(JMA) and of the rotation angle corresponding to a measure of the horizontal component of the ground motion(RotD 100) and the results reveal a visible directional pattern for I_(JMA),while in the case of RotD100 the directional patterns are less visible.  相似文献   

5.
The paper presents results of studying the attenuation of ground accelerations from earthquakes of the Vrancea with magnitudes less that 6.0 at distance greater than 300 km in a narrow sector located northeast of the focal region, within the limits of which are located acting and planned nuclear power plants (NNPs). Attenuation of peak ground accelerations in individual sections along the Vrancea–IRIS OBN station path is approximated by individual functions. It is shown that for a rough estimation of the seismic effect of earthquakes from the Vrancea zone it is acceptable to use the empirical relationship obtained by F.F. Aptikaev. For a more accurate estimate, it needs to be modified by adding a constant, whose value depends on the specific conditions of the NPP sites. It is shown that the results of data analysis on moderate earthquakes can be extrapolated to an earthquake with the maximum possible magnitude for the Vrancea zone and used to estimate the maximum seismic effects at the sites of operating and planned NPPs.  相似文献   

6.
2017年8月8日发生的九寨沟MS 7.0地震,是中国近10年来发生的强震之一,造成了大量建筑破坏、人员伤亡和经济损失,强震台网记录到的最大峰值加速度为0.19g。本文采用Wang等(2015)提出的改进有限断层法模拟了这次地震中部分台站的加速度时程。首先,选取合适的震源模型和输入参数,通过对比模拟结果和地震记录,估计这次地震的应力降大约为4.0MPa,与王宏伟等(2017)的分析结果基本一致。与EXSIM(Motazedian等,2005)方法相比,Wang等(2015)的方法得到的结果在频域上与实际地震记录更相符。同时,合成了强震台站以及断层附近网格点的加速度时程,模拟结果的时程和反应谱与实际记录整体上较为符合,震中附近的PGA分布与震中烈度区基本一致,验证了本文结果的有效性。本文合成的地震动可以为该地区的灾后抗震设计提供一定依据。  相似文献   

7.
Earthquake simulation technologies are advancing to the stage of enabling realistic simulations of past earthquakes as well as characterizations of more extreme events, thus holding promise of yielding novel insights and data for earthquake engineering. With the goal of developing confidence in the engineering applications of simulated ground motions, this paper focuses on validation of simulations for response history analysis through comparative assessments of building performance obtained using sets of recorded and simulated motions. Simulated ground motions of past earthquakes, obtained through a larger validation study of the Southern California Earthquake Center Broadband Platform, are used for the case study. Two tall buildings, a 20‐story concrete frame and a 42‐story concrete core wall building, are analyzed under comparable sets of simulated and recorded motions at increasing levels of ground motion intensity, up to structural collapse, to check for statistically significant differences between the responses to simulated and recorded motions. Spectral shape and significant duration are explicitly considered when selecting ground motions. Considered demands include story drift ratios, floor accelerations, and collapse response. These comparisons not only yield similar results in most cases but also reveal instances where certain simulated ground motions can result in biased responses. The source of bias is traced to differences in correlations of spectral values in some of the stochastic ground motion simulations. When the differences in correlations are removed, simulated and recorded motions yield comparable results. This study highlights the utility of physics‐based simulations, and particularly the Southern California Earthquake Center Broadband Platform as a useful tool for engineering applications.  相似文献   

8.
Large earthquakes at shallow depths commonly excite long-period ground motions in distant sedimentary basins, thereby inflicting damage upon large-scale structures. For example, the 2003 Tokachi-oki earthquake, Japan, damaged oil tanks in the Yufutsu Basin, located 250 km from the epicenter. Similar long-range effects were also observed during the 2004 earthquake off Kii Peninsula, Japan. In this study, we present the results of simulations of these earthquakes undertaken using the finite element method (FEM) with a voxel mesh. In addition, to examine whether the 1906 San Francisco earthquake excited long-period ground motions in the Los Angeles-area basins, we performed long-period ground motion simulations of most of the California region. The FEM simulations confirmed the importance of path effects for the development of long-period ground motions.  相似文献   

9.
We constructed a prototype of the basin and crustal structure model for the Kinki area, southwest of Japan, for the simulation of strong ground motions of hypothetical crustal and subduction earthquakes. We collected results of the deep seismic velocity profiles obtained by the reflection experiments and seismic imaging results, which were conducted in the Kinki area. The obtained profiles give underground velocity structures of the crust, from the surface to the subducting slab. We also gather the basin velocity structure information of the Osaka, Kyoto, Nara, and Ohmi basins. To examine the applicability of the constructed velocity structure model to the ground motion simulation, we simulated waveforms of an intermediate size event occurred near the source area of the hypothetical subduction earthquakes. Simulated ground motions using the basin and crustal velocity structure model are fairly well reproducing the observations at most of stations, and the constructed basin and crustal velocity structure model is applicable for the long-period ground motion simulations.  相似文献   

10.
There is a high possibility of reoccurrence of the Tonankai and Nankai earthquakes along the Nankai Trough in Japan. It is very important to predict the long-period ground motions from the next Tonankai and Nankai earthquakes with moment magnitudes of 8.1 and 8.4, respectively, to mitigate their disastrous effects. In this study, long-period (>2.5 s) ground motions were predicted using an earthquake scenario proposed by the Headquarters for Earthquake Research Promotion in Japan. The calculations were performed using a fourth-order finite difference method with a variable spacing staggered-grid in the frequency range 0.05–0.4 Hz. The attenuation characteristics (Q) in the finite difference simulations were assumed to be proportional to frequency (f) and S-wave velocity (V s) represented by Q = f · V s / 2. Such optimum attenuation characteristic for the sedimentary layers in the Osaka basin was obtained empirically by comparing the observed motions during the actual M5.5 event with the modeling results. We used the velocity structure model of the Osaka basin consisting of three sedimentary layers on bedrock. The characteristics of the predicted long-period ground motions from the next Tonankai and Nankai earthquakes depend significantly on the complex thickness distribution of the sediments inside the basin. The duration of the predicted long-period ground motions in the city of Osaka is more than 4 min, and the largest peak ground velocities (PGVs) exceed 80 cm/s. The predominant period is 5 to 6 s. These preliminary results indicate the possibility of earthquake damage because of future subduction earthquakes in large-scale constructions such as tall buildings, long-span bridges, and oil storage tanks in the Osaka area.  相似文献   

11.
Performance‐based earthquake engineering often requires ground‐motion time‐history analyses to be performed, but very often, ground motions are not recorded at the location being analyzed. The present study is among the first attempt to stochastically simulate spatially distributed ground motions over a region using wavelet packets and cokriging analysis. First, we characterize the time and frequency properties of ground motions using the wavelet packet analysis. The spatial cross‐correlations of wavelet packet parameters are determined through geostatistical analysis of regionalized ground‐motion data from the Northridge and Chi‐Chi earthquakes. It is observed that the spatial cross‐correlations of wavelet packet parameters are closely related to regional site conditions. Furthermore, using the developed spatial cross‐correlation model and the cokriging technique, wavelet packet parameters at unmeasured locations can be best estimated, and regionalized ground‐motion time histories can be synthesized. Case studies and blind tests using data from the Northridge and Chi‐Chi earthquakes demonstrate that the simulated ground motions generally agree well with the actual recorded data. The proposed method can be used to stochastically simulate regionalized ground motions for time‐history analyses of distributed infrastructure and has important applications in regional‐scale hazard analysis and loss estimation. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

12.
— The mapping of the seismic ground motion in Bucharest, due to the strong Vrancea earthquakes is carried out using a complex hybrid waveform modeling method which combines the modal summation technique, valid for laterally homogeneous anelastic media, with finite-differences technique, and optimizes the advantages of both methods. For recent earthquakes, it is possible to validate the modeling by comparing the synthetic seismograms with the records. We consider for our computations the frequency range from 0.05 to 1.0 Hz and control the synthetic signals against the accelerograms of the Magurele station, low-pass filtered with a cut-off frequency of 1.0 Hz of the 3 last major strong (Mw > 6) Vrancea earthquakes. Using the hybrid method with a double-couple seismic source approximation, scaled for the source dimensions and relatively simple regional (bedrock) and local structure models, we succeeded in reproducing the recorded ground motion in Bucharest at a satisfactory level for seismic engineering. Extending the modeling to the entire territory of the Bucharest area, we construct a new seismic microzonation map, where five different zones are identified by their characteristic response spectra.  相似文献   

13.
用随机模拟方法研究设定地震地面运动   总被引：1，自引：0，他引：1       下载免费PDF全文
用随机模拟方法研究设定地震地面运动可分两步进行：（1）采用中小地震的数字观测资料确定研究区路径、场地参数;（2）把确定的参数应用到研究区的强地面运动随机模拟中. 为此,本文首先采用了一种可行的方法,分离软基岩场地效应和非弹性衰减的影响,并把二者分别确定出来. 研究区北部中软基岩场地的平均效应在2～4Hz频率范围为15倍左右;研究区的S波品质因子为QS＝278f[KG*2]0.346. 把这些参数用于研究区的场地和路径模型中,并选择单拐角频率震源谱模型,随机模拟了研究区未来中强地震可能在北天山中段可能造成的地面运动,模拟加速度时程和反应谱可以服务于本地区的地震灾害预测和建筑物可靠性验算.  相似文献   

14.
First frequency-dependent empirical scaling equations of pseudo-relative velocity spectral amplitudes (PSV) of strong earthquake ground motions in the former Yugoslavia were introduced in the mid-1990s by Lee and Trifunac (1990) [15]. This followed the development of the Fourier spectral amplitudes (FS) scaling equations by Lee and Trifunac (1993) [17] in terms of earthquake source parameters, and the region-specific frequency dependent attenuation function given by Lee and Trifunac (1992) [16]. More recently, a new frequency-dependent attenuation function was developed for central and eastern Serbia for earthquakes of intermediate and large magnitudes and for large epicentral distances—exceeding 300 km—suggested by Lee et al. (2016) [19] that occur in the Vrancea source region in Romania. In this paper we use this frequency-dependent attenuation function to develop empirical scaling equations for PSV spectral amplitudes in Serbia. These scaling equations will form a basis for macro- and micro-zoning earthquake hazard studies in Serbia.  相似文献   

15.
We present the regional ground-motion prediction equations for peak ground acceleration (PGA), peak ground velocity (PGV), pseudo-spectral acceleration (PSA), and seismic intensity (MSK scale) for the Vrancea intermediate depth earthquakes (SE-Carpathians) and territory of Romania. The prediction equations were constructed using the stochastic technique on the basis of the regional Fourier amplitude spectrum (FAS) source scaling and attenuation models and the generalised site amplification functions. Values of considered ground motion parameters are given as the functions of earthquake magnitude, depth and epicentral distance. The developed ground-motion models were tested and calibrated using the available data from the large Vrancea earthquakes. We suggest to use the presented equations for the rapid estimation of seismic effect after strong earthquakes (Shakemap generation) and seismic hazard assessment, both deterministic and probabilistic approaches.  相似文献   

16.
The Vrancea subcrustal earthquakes of August 30,1986 and May 30,1990 are the two most recent seismic events that have occurred in Romania with moment magnitudes M W ≥ 6.9.The spectral analysis of the strong ground motions recorded in Bucharest reveals that despite small differences in magnitude between the 1986 and 1990 earthquakes,their frequency contents are very different,sometimes even opposing.The main focus of this study is to conduct a comparative analysis of the response spectra in terms of the bi-normalized response spectra(BNRS) proposed by Xu and Xie(2004 and 2007) for strong ground motions recorded in Bucharest during these two seismic events.The mean absolute acceleration and relative velocity response spectra for the two earthquakes are discussed and compared.Furthermore,the mean bi-normalized absolute acceleration and normalized relative velocity response spectra with respect to the control period T C are computed for the ground motions recorded in Bucharest in 1986 and 1990.The predominant period T P is also used in this study for the normalization of the spectral period axis.Subsequently,the methodology proposed by Martinez-Perreira and Bommer(1998) is applied in order to estimate the seismic intensity of the two events.The results are discussed and several conclusions regarding the possibility of using the bi-normalized response spectra(BNRS) are given.  相似文献   

17.
Strong-motion data from large (M ≥ 7.2) shallow crustal earthquakes invariably make up a small proportion of the records used to develop empirical ground motion prediction equations (GMPEs). Consequently GMPEs are more poorly constrained for large earthquakes than for small events. In this article peak ground accelerations (PGAs) observed in 38 earthquakes worldwide with M ≥ 7.2 are compared with those predicted by eight recent GMPEs. Well over half of the 38 earthquakes were not considered when deriving these GMPEs but the data were identified by a thorough literature review of strong-motion reports from the past 60 years. These data are provided in an electronic supplement for future investigations on ground motions from large earthquakes. The addition of these data provides better constraint of the between-event ground-motion variability in large earthquakes. It is found that the eight models generally provide good predictions for PGAs from these earthquakes, although there is evidence for slight under- or over-prediction of motions by some models (particularly for M > 7.6). The between-event variabilities predicted by most models match the observed variability, if data from two events (2001 Bhuj and 2005 Crescent City) that are likely atypical of earthquakes in active regions are excluded. For some GMPEs there is evidence that they are over-predicting PGAs in the near-source region of large earthquakes as well as over-predicting motions on hard rock. Overall, however, all the considered models, despite having been derived using limited data, provide reliable predictions of PGAs in the largest crustal earthquakes.  相似文献   

18.
Characterization of Earthquake Strong Ground Motion   总被引：1，自引：0，他引：1  
— Some underwater landslides are triggered by strong ground motions caused by earthquakes. This paper reviews current concepts and trends in the characterization of strong ground motion. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude-distance-soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near-fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes.  相似文献   

19.
Vrancea major intermediate-depth earthquakes produced extreme damage in Bucharest city, located at about 165 km epicenter distance. Our purpose is to investigate the influence of local geological conditions upon the seismic motion in Bucharest in case of large (M>7) Vrancea earthquakes. Two input data sets are used: (a) geological, geotechnical and geophysical information, including in situ measurements, and (b) acceleration recordings of Vrancea earthquakes. Local response evaluation based on first dataset is confirmed by the spectral analysis of the earthquake records. Two main features are outlined: non-stationarity of ground motion dynamic amplification from one event to other and inadequacy of limiting the investigation depth to uppermost 30 m to evaluate ground dynamic characteristics. Consequently (1) we cannot extrapolate the ground motion response determined for moderate and small earthquakes to anticipate the effects of the large Vrancea shocks and (2) the local response is controlled by the entire package of Quaternary deposits which are significantly deeper than 30 m depth beneath Bucharest Area.  相似文献   

20.
Even though a number of parameters have been proposed in the literature for measuring the capacity of earthquake ground motions to damage structures, most of them are not consistent with building damage observed during earthquakes. In this study, a parameter for measuring seismic damage capacity is proposed. It uses the energy dissipated by a structure in inelastic deformations and a structural overall drift, and it is evaluated for three typical ground motions recorded in severe earthquakes. By using this parameter, consistent results with building damage observed in these earthquakes are obtained, which indicate the importance of displacement control for minimizing seismic damage.  相似文献   

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