Date of Award
Doctor of Philosophy
Three important topics have been studied in this dissertation. First, the effects of deep soil deposits of the Mississippi embayment in ground motion amplification have been studied. Using the results of one-dimensional analyses, a parametric model is developed for the region to estimate the ground motion amplification. The averaged shear-wave velocity in the upper 30 meter, Vs30, ranging from 220 to 800 m/s and deposit thickness varying from 70 to 750m, are considered in the estimation of the ground motion amplification with respect to a generic bedrock profile of the Mississippi embayment. Results indicate that site factors suggested by seismic codes cannot capture the site properties of the Mississippi embayment and are not appropriate for the region. In the second part, a new step-by-step method is developed to select a set of ground motions which takes into account a site-specific Probabilistic Seismic Hazard Analysis (PSHA) and the associated uncertainties through the defined logic tree. In the proposed method, after capturing the variability of the Uniform Hazard Response Spectrum (UHRS), I used a Monte Carlo procedure to produce a set of response spectra that has mean equals to the target and variability close to the variability of the target at all the spectral periods. Each member of the generated set is called individual target response spectra, and ground motions from the database of real data and also synthetic ground motions are selected based on their similarity with the individual target response spectra. The method’s procedure is defined through studying a sample site in North of the Mississippi embayment.In the last part of the study I developed a model for the ratio of Vertical to Horizontal component of earthquakes (V/H ratio) for the Mississippi embayment. This model can be used in developing the site-specific vertical design spectrum for the region by scaling the horizontal design spectrum resulting from a PSHA. The input parameters of the applied functional form are magnitude, distance, and Vs30. The proposed model has the advantage of including site response of the study area.
dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.
Malekmohammadi, Mojtaba, "Statistical Study of Ground Motion Amplification in the Mississippi Embayment" (2013). Electronic Theses and Dissertations. 650.