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Sigma Action Plan. 1. Magnitude Dependence of mainshocks (Ken/Yousef) 1a. Add small mag mainshocks to NGA set. 1b. Add additional large mag data (eg. Wenchuan) 1c. Evaluate mag dependence of mainshock sigma using updated data set 1d. Compare MS and AS sigma
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Sigma Action Plan • 1. Magnitude Dependence of mainshocks (Ken/Yousef) • 1a. Add small mag mainshocks to NGA set. • 1b. Add additional large mag data (eg. Wenchuan) • 1c. Evaluate mag dependence of mainshock sigma using updated data set • 1d. Compare MS and AS sigma • 2. Applicability of WUS (active region) sigma to ENA (Norm) • 2a. Review approaches used in EPRI (2006) report for evaluating applicability • Identify other possible methods/checks • Stress parameter distributions for EUS and WUS • Depth dependence of the variability • 2b. Compare sigma from small mag CA data with sigma from small mag ENA data • M>3, focus on R< 100 km.
Sigma Action Plan • 3. Stability of sigma for active regions (melanie/norm) • 3a. Compare well constrained sigma for other regions (e.g. Japan) to the NGA sigmas • For Japan, consider downhole vs surface to account for shallow site effects that may increase sigma • 4. Stress-parameters (walt) • 4a. Comparison of small mag stress-parameters for CA and ENA • M>3 • 4b. Depth dependence of stress-parameters • Look at more CA data to constrain scaling • 4c. Saguenay • How to treat this event in the estimation of std dev (Ds)
Sigma action plan • Propagation of mag /dist conversion (Gab) • Point source vs finite source for hazard • Check if too much uncertainty is being propagated in hazard calc • Mag conversion should not happen • Outlier data • How to deal with outliers in ground motion
Sigma Action Plan • Single path sigma (melanie/norm) • Compare results for small and large mag eqk using southern CA data. • Does weak motion tell you something about the site and path terms for strong motion? • Verticals (ellen) • PGV (ellen)
Median GM plan • How much do we need to increase the range of models to capture the epistemic uncertainty in median (Bob Youngs, Fleur) • Scherbaum approach