Determination On Related Parameters For Intensity Envelope Function Of Ground Motion

Intensity envelope function is used to describe the change characteristics of theamplitude of ground motion, from weak to strong and then to the weak in time,which can not only show the non-stationary of ground motion intensity, but alsoreflect the duration of strong ground motion. Intensity envelope function is animportant parameter in the synthesis of artificial ground motion time history forseismic safety evaluation, which has attracted much attention from engineeringseismology researchers.In this paper, the study on the determination of related parameters of theintensity envelope function, based on the strong motion observation data of CSMNCand NGA strong motion database. The main contents are shown as follows:1.The development process of intensity envelope function and latest researchachievements are systematically reviewed and summarized, and the developmenthistory of the intensity envelope function models and their parameters, as well as therelevant information of the ground motion duration are introduced. In addition, theengineering significance of the intensity envelope function in the ground motionsynthesis is discussed.2.The strong motion data used in this paper are organized. Collected andorganized the bedrock strong motion data of CSMNC and PEER-NGA strong motiondatabase, which is associated process. The surface wave magnitude is from4.0to8.0, the epicenter distance is between0—300km. For the convenience of uniformlyusing the two sets of data, the moment magnitudes of NGA ground motion databaseand the local earthquake magnitudes of several seismic stations are converted to thesurface wave magnitudes, while the local earthquake magnitudes of several seismicstations in China are converted to the surface wave magnitudes.3.The related parameters of the intensity envelope function are determined, inwhich the multi-peak search method is used to obtain the envelope curve. Comparedwith other methods, this method simple and better reflects the actual situation.Furthermore, the influence of the the vertical&horizontal components and fourkinds of energy duration on the calculation results of the intensity envelope functionare compared and analyzed. Finally, the energy duration of70%is the best choicefor the intensity envelope function.4.Based on the strong motion observation data home and abroad, the weightedleast-square of single random variable is applied to statistical regression of relatedparameters of intensity envelope function. The relationship between intensityenvelope function parameters and magnitude, epicentral distance is given, and theresiduals of intensity envelope function parameters relative to the magnitude andepicentral distance are drawn. Finally, the statistical regression differences betweenthe vertical and horizontal components as well as the intensity envelope function parameters are compared and analyzed.