Date of Award
Doctor of Philosophy
Charles V Camp
Roger W Meier
This dissertation deals with the stochastic simulation of the Next Generation Attenuation- East (NGA-East) ground-motion models and a proposing a new method of calculating the long-period transition period parameter, TL, in the seismic building codes. The work of this dissertation is carried out in two related studies. In the first study, a set of correlated and consistent seismological parameters are estimated in the in Central and Eastern United States (CEUS) by inverting the median 5%-damped spectral acceleration (PSA) predicted from the Next Generation Attenuation-East (NGA-East) ground-motion models (GMMs). These seismological parameters together form a point-source stochastic GMM. Magnitude-specific inversions are performed for moment magnitude ranges Mw 4.0-8.0, rupture distances Rrup = 1-1000 km and periods T = 0.01-10s, and National Earthquake Hazard Reduction Program site class A conditions. In the second study, the long-period transition period parameter TL is investigated, and an alternate seismological approach is used to calculate it. The long-period transition period parameter is utilized in the determination of the design spectral acceleration of long-period structures. The estimation of TL has remained unchanged since its original introduction FEMA 450-1/2003; The calculation is loosely based on a correlation between modal magnitude Mw and TL that does not account for different seismological parameters in different regions of the country. This study will calculate TL based on the definition of corner period, and will include two seismological parameters, the stress parameters Δσ and crustal velocity in the source region β, in its estimation. The results yield a generally more conservative (or longer) estimation of TL than the estimation that is currently used in engineering design standards.
Dissertation or thesis originally submitted to ProQuest
Assadollahi, Christine, "An Equivalent Point-Source Stochastic Model of the NGA-East Ground-Motion Models and a Seismological Method for Estimating the Long-Period Transition Period TL" (2023). Electronic Theses and Dissertations. 3050.