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1.
This paper presents a performance-based methodology for the assessment of seismic vulnerability and capacity of buildings. The vulnerability assessment methodology is based on the HAZUS methodology and the improved capacity- demand-diagram method. The spectral displacement (Sd) of performance points on a capacity curve is used to estimate the damage level of a building. The relationship between Sd and peak ground acceleration (PGA) is established, and then a new vulnerability function is expressed in terms of PGA. Furthermore, the expected value of the seismic capacity index (SCev) is provided to estimate the seismic capacity of buildings based on the probability distribution of damage levels and the corresponding seismic capacity index. The results indicate that the proposed vulnerability methodology is able to assess seismic damage of a large number of building stock directly and quickly following an earthquake. The SCev provides an effective index to measure the seismic capacity of buildings and illustrate the relationship between the seismic capacity of buildings and seismic action. The estimated result is compared with damage surveys of the cities of Dujiangyan and Jiangyou in the M8.0 Wenchuan earthquake, revealing that the methodology is acceptable for seismic risk assessment and decision making. The primary reasons for discrepancies between the estimated results and the damage surveys are discussed.  相似文献   

2.
The distribution of the intensity of the Mojiang M_S5.9 earthquake in Yunnan Province is expounded, and the damage characteristics of buildings and the damage ratio and seismic damage index of various building structures in each intensity area are compared with those of The Chinese Seismic Intensity Scale. The main basis and method of seismic intensity assessment are discussed in this paper. It is concluded that: ① The seismic intensity should be based on the earthquake damage of the housing structure, which takes up a high ratio in the seismic intensity assessment. It is recommended that seismic intensity is estimated by calculating the average seismic damage index. ② The highest intensity of the Mojiang M_S5.9 earthquake is Ⅷ degrees, with the long axis trending in the north-west direction. The area above Ⅶ degrees is 5,180 km~2. ③ The intensity distribution of the Mojiang M_S5.9 earthquake meets the national standard and the distribution law of seismic intensity in Yunnan.  相似文献   

3.
Seismic hazard assessment based on urban active faults can provide scientific bases for city planning and projectconstruction,while numerical simulation of strong ground motion is an important method for seismic hazard pre-diction and assessment.A 3-D physical model in conformity with real strata configuration of(mainly)the Quater-nary is a prerequisite to ensure the reliability of the simulation results.In this paper,we give a detailed account ofthe technical scheme and process for creating a 3-D physical model in Kunming basin.The data used are synthe-sized from seismogeological data,borehole data,topographic data,digital elevation mode(DEM)data,seismicexploration results and wave velocity measurements.Stratigraphic division is based mainly on shear wave velocity,with strata sequence taken into consideration.The model construction is finally accomplished with ArcGIS andmany relevant programming techniques via layer-by-layer stacking(in depth direction)of the adjacent mediuminterfaces(meshes).Meanwhile,a database of 3-D physical models is set up,which provides model data and pa-rameters for strong ground motion simulation.Some processing methods and significant issues are also addressedin the paper in accordance with different types of exploration and experimental data.  相似文献   

4.
Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the test data, a relationship between maximum inter-story drift and damage state is established. Equations of variation of structural characteristics (natural frequency and equivalent stiffness) with overall drifts are derived by data fitting, which can be used to estimate structural damage state if structural characteristics can be measured. A comparison of the analytical and experimental results show that both the commonly used equivalent beam and fiber element models can simulate the nonlinear seismic response of structures very well. Finally, conclusions associated with seismic design and damage evaluation of RC structures are presented.  相似文献   

5.
Remote sensing classification methods can be classified as supervised and unsupervised catalogs. The maximum likelihood method (MLH) is a super-vised classification method,which is widely used in the remote sensing data classification and produces good results[1]. In the MLH, the parameters are esti-mated, assuming that the samples are normally dis-tributed in spectral space, to determine the mean vec-tor and covariance matrix of all classes. In most cases, however, the samples are not norma…  相似文献   

6.
Based on raw data from dams damaged in the Wenchuan earthquake, including many that were severely damaged, characteristics and factors that influenced the damage are discussed in this paper. Findings from this study include: severely damaged dams were densely distributed along the seismologic fault; small dams, especially small earth-rock dams, had the most serious damage that was caused by a variety of factors; the most serious damage was caused by seismic waves; damage was aggregated by aftershocks; and the extent of the damage patterns increased with the seismic intensity. Damage patterns varied in different intensity zones and cracking was the most common type of damage. Most of the dams had a good base with relatively high bearing capacity, and the walls of the earth-rock dams were mostly of clay soil. This type of base and body material mitigated some of the damage to dams. Reservoir maintenance and other factors also have a significant impact on the seismic safety of the dam. Finally, some recommendations to reduce seismic damage to dams are proposed.  相似文献   

7.
The method of fuzzy mathematics for simultaneous assessment of time and intensity of earthquake hazards has been studied.This method is based on fundamental statistical indices of regional seismicity.Applying the retrieval method of fuzzy information,we can classify the time and intensity into several intervals and classes of seismic activity,then the possible time interval of large earthquakes with magnitude of M≥Ms can be estimated in a given region.Based on the preceding idea,an FRPP program is constructed.For the automatic data processing when this method is used,it is very important to design the statistical process of each index decomposition so that the program could be fit to a different sample discussed.There are some functions in the FRPP program.The man-made impact on results is reduced to the minimum as far as possible.Computation time is saved.There is a menu on which time interval,index,intensity class,and output data all can be selected.The catalog input that can be displayed on the scre  相似文献   

8.
There is a certain degree of ambiguity associated with remote sensing as a means of performing earth observations.Using interval-valued data to describe clustering prototype features may be more suitable for handling the fuzzy nature of remote sensing data,which is caused by the uncertainty and heterogeneity in the surface spectral reflectance of ground objects.After constructing a multi-spectral interval-valued model of source data and defining a distance measure to achieve the maximum dissimilarity between intervals,an interval-valued fuzzy c-means(FCM)clustering algorithm that considers both the functional characteristics of fuzzy clustering algorithms and the interregional features of ground object spectral reflectance was applied in this study.Such a process can significantly improve the clustering effect;specifically,the process can reduce the synonym spectrum phenomenon and the misclassification caused by the overlap of spectral features between classes of clustering results.Clustering analysis experiments aimed at land cover classification using remote sensing imagery from the SPOT-5 satellite sensor for the Pearl River Delta region,China,and the TM sensor for Yushu,Qinghai,China,were conducted,as well as experiments involving the conventional FCM algorithm,the results of which were used for comparative analysis.Next,a supervised classification method was used to validate the clustering results.The final results indicate that the proposed interval-valued FCM clustering is more effective than the conventional FCM clustering method for land cover classification using multi-spectral remote sensing imagery.  相似文献   

9.
The New Seismic Zoning Map of China was prepared from 1987 to 1990 and officially promulgated in 1991.In comparison with the previous two seismic zoning maps prepared in 1957 and 1977,some new methods were applied to upgrade the method currently used for seismic hazard analysis.First,a probabilistic method was used instead of the deterministic analysis was used for previous mapping.Second,by taking advantages of the long history of historical seismic data in China,the nonhomogeneity of seismicity both in space and in time has been fully considered and hence the over-and/or underestimation of seismic hazard could be avoided.Third,the results of middle-and long-term earthquake prediction based on tectonic evidence have been incorporated into seismic hazard analysis.In addition,the attenuation laws for both intensity and peak acceleration of strong motion as the mapping parameters are also presented.Finally,an evaluation of the New Seismic Map and its effect on engineering application,such as aseismic desi  相似文献   

10.
In order to minimize uncertainty of the inversed parameters to the largest extent by making full use of the limited information in remote sensing data, it is necessary to understand what the information flow in quantitative remote sensing model inversion is, thus control the information flow. Aiming at this, the paper takes the linear kernel-driven model inversion as an example. At first, the information flow in different inversion methods is calculated and analyzed, then the effect of information flow controlled by multi-stage inversion strategy is studied, finally, an information matrix based on USM is defined to control information flow in inversion. It shows that using Shannon entropy decrease of the inversed parameters can express information flow more properly. Changing the weight of a priori knowledge in inversion or fixing parameters and partitioning datasets in multi-stage inversion strategy can control information flow. In regularization inversion of remote sensing, information matrix based on  相似文献   

11.
Based on faults surveying and research data in the Tianjin offshore areas, through studying tectonic structure, Quaternary activity, deep structure, stress and strain fields and seismicity in the Tianjin offshore areas, the activity and tectonic features of the faults are determined synthetically. Using seismo-geological data, and the historical and modern seismicity data, the frequency-magnitude relationship model normalized by 500a is established and based on the relationship between the upper limit of maximum magnitude Mu and at/b, the maximum magnitudes of the sea section of the Haihe river fault and the Haiyi fault are calculated. Then Poisson probability model is adopted and the quantitative parameters, such as the maximum magnitude, occurrence probability, recurrence cycle of the faults in the south Tianjin offshore areas in the coming 50 - 200a, are calculated.  相似文献   

12.
In this paper, using the 1999 ~ 2007 GPS velocity field data, and by choosing the optimal block model, we obtained the deformation models applicable to the boundary zones of major blocks and the slip rates of block boundary faults on the mid-southern segment of the North-South Seismic Belt. The results show that： on the Longmenshan fault zone, the tensional and compressive slip rate is small on the Baoxing-Wenchuan segment, about 0. 5 ~ 1.8mm·a^-1, and the rate is relatively significant on the segment of the Wenchuan--Maoxian, as 1.8 ~3.8mm·a^-1; on the Xianshuihe fault belt, there is a certain difference in spatial distribution between the tensional slip rag.e and strike-slip rate： the tensional slip rate （ 8. lmm~a-1） is bigger than the sinistral strike-slip rate （ 4.8mm·a^-1） at the north of the Luhuo region; the tension and compression slip rate is basically the same as the strike-slip rate at Luhuo-Dawu; the Dawu-Kangding section presents a trend of decreased strike-slip rate and increased tensional slip rate; the Kangding-ghimian segment shows a strike-slip nature; the strike-slip rate is significantly greater than the tension/compression rate on the Xiaojiang fault zone; the slip rate on the Red River fault zone shows obvious spatial segmentation, the slip rate is smaller in its northwest part, but with a certain amount of tensional/compression component, 4. 7mm·a^-1 on the Jingdong segment. The segment east of Jingdong （ western Gejiu） is mainly of strike-slip, with a slip rate of 4. 5mm·a^-1.  相似文献   

13.
It is of great significance to make comparative analyses of seismic fortification criteria at home and abroad for improving the anti-seismic capability of electrical equipment and revising the relevant national standards. A brief overview of American, Japanese, IEC standards and Chinese seismic design codes for electrical equipment is presented. Differences between these seismic fortification standards of electrical equipment are compared and analyzed in respect of the goal and level of seismic fortification and the seismic design spectrum. The advantages and disadvantages of Chinese standards are pointed out. Through learning from foreign experience on the determination of seismic fortification standards, recommendations are made for the improvement and revision of Chinese seismic fortification standards for electrical equipment.  相似文献   

14.
The research and achievements made on seismic subsidence of loess, obtained over the past 30 years, were reviewed. Seismic Subsidence of Loess （SSL） has been verified by microstructure characteristics, dynamic triaxial experiments, and in-situ explosion tests, and has become an important subject in the field of seismic loess engineering research. While, the research is still in the stage of theoretical study of saturated soil, and there are no representative cases of seismic subsidence of loess in historical earthquakes. It is difficult to express structure characteristics using microstructure morphology. While, soil mechanics are available methods for this. Seismic subsidence judgment is absolute in some certain value ranges for several parameters. Therefore, probabilistic judgment should be developed. The seismic subsidence ratio is estimated mostly by empirical formulas or semi- empirical and semi-theoretical formulas, which are based on laboratory data. These formulas are not established on the basis of physical process and mechanics of seismic subsidence, and this leads to more variables, complicated computation, and poor practicability. To solve these problems, we need to distinguish the main factors and corresponding variables, to establish a mechanics model for seismic subsidence estimation, and to characterize its physio-mechanical process. The key of anti-seismic subsidence treatment is to reduce the seismic subsidence property of soils, and to lower the interaction between the soil body and underground structures.  相似文献   

15.
The Ms7.0 Lushan earthquake on April 20, 2013 is another destructive event in China since the Ms8.0 Wenchuan earthquake in 2008 and Ms7.1 Yushu earth- quake in 2010. A large number of strong motion recordings were accumulated by the National Strong Motion Obser- vation Network System of China. The maximum peak ground acceleration （PGA） at Station 51BXD in Baoxing Country is recorded as -1,005.3 cm/s2, which is even larger than the maximum one in the Wenchuan earthquake. A field survey around three typical strong motion stations confirms that the earthquake damage is consistent with the issued map of macroseismic intensity. For the oscillation period 0.3-1.0 s which is the common natural period range of the Chinese civil building, a comparison shows that the observed response spectrums are considerably smaller than the designed values in the Chinese code and this could be one of the reasons that the macroseismic intensity is lower than what we expected despite the high amplitude of PGAs. The Housner spectral intensities from 16 stations are also basically correlated with their macroseismic intensities, and the empirical distribution of spectral intensities from Lushan and Wenchuan Earthquakes under the Chinese scale is almost identical with those under the European scale.  相似文献   

16.
We perform Rayleigh wave tomography in east Guangdong and its surrounding regions by applying the ambient noise method to broadband data recorded at 26 stations from Guangdong, Fujian and Jiangxi Digital Seismic Networks. Cross-correlations of vertical- component ambient noise data are computed in one-day segments and stacked over seven months from March to September, 2011. Then Rayleigh wave group dispersion curves are measured using the frequency-time analysis method. Group velocity maps at periods from 5s to 15s are inverted. The resulting group velocity maps generally show good correlation with tectonic features, reflecting the velocity variations in the shallow crust. The basin areas are clearly resolved with lower group velocities at the short periods due to thick sedimentary layers, and the mountain areas with higher group velocities due to thin sedimentary layers. The variations of group velocity on the map can draw out the distribution of basins and mountains in study areas. The geothermal field can change the group velocity obviously, and lower group velocities are always found in high geothermal areas. The velocity maps indicate that a low-velocity layer may be found in the study areas.  相似文献   

17.
The correlation of the scaled energy,e = Es/ Mo, versus earthquake magnitude, Ms, is studied based on two models： （1） Model 1 based on the use of the time function of the average displacements, with a ω^-2 source spectrum, across a fault plane; and （2） Model 2 based on the use of the time function of the average displacements, with a ω^-3 source spectrum, across a fault plane. For the second model, there are two cases： （a） As ζ= T, where r is the rise time and T the rupture time, lg（e） - -Ms; and （b） As ζ 〈〈 T, lg（e）- -（1/2）Ms. The second model leads to a negative value of e. This means that Model 2 cannot work for studying the present problem. The results obtained from Model 1 suggest that the source model is a factor, yet not a unique one, in controlling the correlation of e versus Ms.  相似文献   

18.
Based on the network monitoring data and field investigations, the basic characteristics of the Ms4. 9 earthquake at the juncture of Gaoyou and Baoying in Jiangsu Province on July 20, 2012 have been introduced, and the focal mechanism solutions have also been obtained. According to the regional tectonic features and site macroscopic survey, the occurrence of the earthquake was probably related to the Yangchacang-Sangshutou fault. Based on site survey data, both the evaluation criterion of seismic intensity of this region and the seismic intensity maps have been proposed. According to the damage characteristics of brick-concrete structure and brick-wood structure, the main reasons of serious damage for buildings are poor foundation conditions, low seismic bearing capacity, poor quality of construction and disrepair. Considering the differences of earthquake damage in the different regions, advice on accelerating the new rural construction, improving the resistance against earthquake disasters of rural residential areas and strengthening the seismogenic research on strong and moderate size earthquake is proposed, which will be possibly helpful for earthquake damage survey, prediction and prevention.  相似文献   

19.
The earthquake occurred in Lushan County on 20 April, 2013 caused heavy casualty and economic loss. In order to understand how the seismic energy propagates during this earthquake and how it causes the seismic haz- ard, we simulated the strong ground motions from a rep- resentative kinematic source model by Zhang et al. （Chin J Geophys 56（4）：1408-1411, 2013） for this earthquake. To include the topographic effects, we used the curved grids finite difference method by Zhang and Chen （Geophys J Int 167（1）：337-353, 2006）, Zhang et al. （Geophys J Int 190（1）：358-378, 2012） to implement the simulations. Our results indicated that the majority of seismic energy con- centrated in the epicentral area and the vicinal Sichuan Basin, causing the XI and VII degree intensity. Due to the strong topographic effects of the mountain, the seismic intensity in the border area across the northeastern of Boxing County to the Lushan County also reached IX degree. Moreover, the strong influence of topography caused the amplifications of ground shaking at the moun- tain ridge, which is easy to cause landslides. These results are quite similar to those observed in the Wenchuan earthquake of 2008 occurred also in a strong topographic mountain area.  相似文献   

20.
The April 20, 2013 Lushan earthquake which occurred in Sichuan, China had only moderate thrust. However, the computed seismic moments （M0） for the Lushan earthquake calculated by several institutions differ significantly from 0.4 × 1019 to 1.69 ×019 Nm, up to four times difference. We evaluate ten computed Mos by using normal mode observations from superconducting gravimeters in Mainland China. We compute synthetic normal modes on the basis of moment tensor solutions and fit them to the observed normal modes. Comparison of our results indicates that Mo is the main cause for some large differences between observations and synthetics. We sug- gest that a moment magnitude of Mw6.6, corresponding to a Mo of 0.97-1.08 × 1019 Nm, characterizes the size and strength of the seismic source of the Lushan earthquake.  相似文献   

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