Model and parametric uncertainty in source-based kinematic models of earthquake ground motion

Bulletin of the Seismological Society of America
By: , and 

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Abstract

Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric uncertainty for changes in rupture velocity. We find that the combined model uncertainty and random variability of the simulations is in the same range as the variability of regional empirical ground-motion data sets. The majority of the standard deviations lie between 0.5 and 0.7 natural-log units for response spectra and 0.5 and 0.8 for Fourier spectra. The estimate of model epistemic uncertainty, based on the different model predictions, lies between 0.2 and 0.4, which is about one-half of the estimates for the standard deviation of the combined model uncertainty and random variability. Parametric uncertainty, based on variation of just the average rupture velocity, is shown to be consistent in amplitude with previous estimates, showing percentage changes in ground motion from 50% to 300% when rupture velocity changes from 2.5 to 2.9 km/s. In addition, there is some evidence that mean biases can be reduced by averaging ground-motion estimates from different methods.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Model and parametric uncertainty in source-based kinematic models of earthquake ground motion
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120110028
Volume 101
Issue 5
Year Published 2011
Language English
Publisher Seismological Society of America
Publisher location El Cerrito, CA
Contributing office(s) Geologic Hazards Science Center
Description 22 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Bulletin of the Seismological Society of America
First page 2431
Last page 2452
Online Only (Y/N) N
Additional Online Files (Y/N) N