New Empirical Model for Vertical to Horizontal Ratio of Earthquake Components for Central and Eastern North America and Comparison With Existing Models

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

An empirical ground motion model is developed for the response spectral ratio of vertical-to-horizontal (V/H) components of earthquakes for the Central and Eastern United States (CENA) and Gulf Coast region. The model can be used to develop site-specific vertical design spectrum by scaling the horizontal design spectrum resulting from a site-specific study. The functional form for the proposed model considers three distinct components for source, path, and site terms. The model evaluation is based on a comprehensive set of regression analyses of the Next Generation Attenuation (NGA-East) database of CENA recordings with the moment magnitude Mw ≥ 3.4 and the rupture distance RRup < 1000 km.

The Pseudo Spectral Accelerations (PSAs) from the NGA-East database are the 50th percentile (or median) PSA value computed from the orthogonal horizontal motions rotated through all possible non-redundant rotation angles, known as the RotD50. The RotD50 values are used along with the vertical PSAs to perform regression analysis using the nonlinear mixed-effects regression algorithm. The model is used to calculate and compare site-specific vertical design spectra for a site in New York and results were compared with existing models.

Presenting Author: Mojtaba Malek

Authors