Performance of NGA-East GMMs and site amplification models relative to CENA ground motions

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We investigate bias in ground motions predicted for Central and Eastern North America (CENA) using ground motion models (GMMs) combined with site amplification models developed in the NGA-East project. Bias is anticipated because of de-coupled procedures used in the development of the GMMs and site amplification models. The NGA-East GMMs were mainly calibrated by adjusting CENA data to a reference site condition using a site amplification model appropriate for active tectonic regions. Hence, these GMMs are likely biased relative to the CENA reference site condition (3000 m/sec shear wave velocity). Moreover, the NGA-East site amplification model recommended for hazard applications contains a simulation-based term for amplification between the reference condition and time-averaged shear wave velocity VS30=760 m/sec, which is uncertain and has not been calibrated against data from sites with that reference condition. Using the NGA-East dataset, we apply mixed-effects residual analysis and identify that period-dependent bias in 5% damped response spectral acceleration is present across a wide frequency range, but is strongest (i.e., overestimating by a factor of 2) at short oscillator periods <0.2 sec. Ongoing work to remedy this bias consists of expanding the NGA-East dataset with more recent recordings and enhanced metadata, particularly regarding site conditions.

Publication type Conference Paper
Publication Subtype Conference Paper
Title Performance of NGA-East GMMs and site amplification models relative to CENA ground motions
Year Published 2022
Language English
Publisher Earthquake Engineering Research Institute
Contributing office(s) Earthquake Science Center
Description 4 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings from the 12th national conference on earthquake engineering
Conference Title 12th National Conference on Earthquake Engineering
Conference Location Salt Lake City, UT
Conference Date Jun 27 - Jul 1, 2022
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