| Seismic parameters are an important measurement in terms of describing the characteristics(amplitude,frequency,and duration)of ground motion.Currently,the most popular used parameters of ground motion are PGA(peak ground acceleration)and Sa(spectral acceleration).However,there is no single ground-motion parameter that can fully and effectively reflect the all the characteristics of seismic damage(e.g.,PGA only can reflect the information of amplitude of ground motion).In order to more comprehensively describe the characteristics of ground motion and its potential damage,and meet the needs of engineering application,scientists have been seeking the ground-motion parameters which can characterize the multiple attributes of ground motion and the specific earthquake damage.Several studies have found that Ia(Arias intensity),CAV(Cumulative absolute velocity)and Newmark displacement are superior to the peak acceleration in the prediction of earthquake-induced landslides,the assessment of liquefaction,the estimation of loss due to earthquake disaster and seismic hazard analysis.Therefore,the study on the characteristics of Ia,CAV and Newmark displacement,and their application in probabilistic seismic hazard analysis can expand our understanding on the characteristics of ground motion and improve the level of prediction on earthquake disaster,which have important scientific and applicable significance.In this paper,according 528 available accelerograms recorded by 177 stations during the Wenchuan Earthquake,and after the baseline correction of seismic records,we calculate the ground-motion parameter of Ia,CAV and Newmark displacement,research some characteristics of them,respectively,and finally study the method of probabilistic seismic hazard analysis based on Ia,CAV and Newmark displacement,respectively.We study the characteristics of spatial distribution and attenuation of Ia,the near-fault effects on Ia,and the correlation between Ia and other seismic parameters of the Wenchuan Earthquake.For the aspect of spatial-distribution characteristics,we compare the difference between vertical and horizontal values of Ia,make a statistical analysis on the distribution of ratio of vertical to horizontal values and inspect the ratio as a function of distance.The same work is done for the value of Fault Normal and Fault Parallel of Ia.For the aspect of attenuation characteristics,we mainly study the attenuation characteristics of Ia in three types of site as well as compare them with the published prediction models of Ia,point out the differences between them and analyzes the reasons for the differences.For the aspect of near-fault effects,we investigate the effects of hanging wall and rupture forward directivity on Ia.Finally,we do the correlation analysis of Ia with PGA and Housner intensity,respectively,establish the respective empirical relationship of Ia with PGA and Housner intensity,and analyze the influence of site conditions on the correlations between these ground-motion parameters.We do the same researches on CAV,which include its characteristics of spatial distribution and attenuation,near-fault effects and correlation with other ground-motion parameters.Particularly,we also study the attenuation characteristics of standard CAV and its correlation with PGA,and analyze the influence of site conditions on them.In addition,we briefly analyzed the attenuation characteristics of Newmark displacement of the Wenchuan Earthquake and its correlations with PGA and Ia.In the second half of this thesis,we study the methods of probabilistic seismic hazard analysis based on Ia and CAV,respectively,and the method of probability seismic landslide hazard analysis based on Newmark displacement by summarizing the relevant theories and methods,establishing the corresponding technical framework,compiling programs and calculating in typical regions for the trial.The researches of this thesis have important scientific significance on the knowledge of the characteristics of Ia,CAV and Newmark displacement in the Wenchuan Earthquake and even the earthquakes under the seismic-geological tectonic environment like Western China.Establishing the relevant technical framework of probabilistic seismic hazard analysis has a strong application value in improving the level of probabilistic seismic hazard analysis and seismic hazard prediction of our country. |
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