Ground motion simulation validation with explicit uncertainty incorporation for small magnitude earthquakes in the Canterbury region (2019)
Type of ContentConference Contributions - Other
- QuakeCoRE: Posters 
This study explicitly investigates uncertainties in physics-based ground motion simulation validation for earthquakes in the Canterbury region. The simulations utilise the Graves and Pitarka (2015) hybrid methodology, with separately quantified parametric uncertainties in the comprehensive physics and simplified physics components of the model. The study is limited to the simulation of 148 small magnitude (Mw 3.5 – 5) earthquakes, with a point source approximation for the source rupture representations, which also enables a focus on a small number of relevant uncertainties. The parametric uncertainties under consideration were selected through sensitivity analysis, and specifically include: magnitude, Brune stress parameter and high frequency rupture velocity. Twenty Monte Carlo realisations were used to sample parameter uncertainties for each of the 148 events. Residuals associated with the following intensity measures: spectral acceleration, peak ground velocity, arias intensity and significant duration, were ascertained. Using these residuals, validation was performed through assessment of systematic biases in site and source terms from mixed-effects regression. Based on the results to date, initial standard deviation recommendations for parameter uncertainties, based on the Canterbury simulations have been obtained.
This work ultimately provides an initial step toward explicit incorporation of modelling uncertainty in simulated ground motion predictions for future events, which will improve the use of simulation models in seismic hazard analysis. We plan to subsequently assess uncertainties for larger magnitude events with more complex ruptures, and events across a larger geographic region, as well as uncertainties due to path attenuation, site effects, and more general model epistemic uncertainties.
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Ground motion simulation validation with explicit uncertainty incorporation for small magnitude earthquakes in New Zealand Neill, Sarah; Bradley, Brendon; Lee, Robin (2020)This study investigates the uncertainty of simulated earthquake ground motions for small magnitude events (Mw 3.5 – 5) in New Zealand. 600 ground motion events were simulated with specified uncertainties in: magnitude, ...
Ground motion simulation validation with explicit uncertainty incorporation for small magnitude earthquakes in the Canterbury region Neill S; Lee R; Bradley, Brendon (2019)This study provides an initial examination of source parameter uncertainty in a New Zealand ground motion simulation model, by simulating multiple event realisations with perturbed source parameters. Small magnitude ...
Ground motion simulation validation with explicit uncertainty incorporation for small-magnitude earthquakes Neill S; Lee R; Stafford P; Bradley, Brendon (2021)This study investigates the uncertainty of simulated earthquake ground motions for smallmagnitude events (Mw 3.5 – 5) in Canterbury, New Zealand. 148 events were simulated with specified uncertainties in: event magnitude, ...