Ability to compute multicomponent Conditional Spectrum using nshmp-haz
BACKGROUND. As described in a BSSA paper by Lin et al. 2013, the USGS used to provide an online tool that gives the "exact" Conditional Mean Spectrum (CMS), which is "exact" because it incorporates different causal earthquake ruptures (i.e., M and R pairs) and different causal ground motion models (GMMs). Instead of using deaggregation to determine the exact CMS, the USGS used an "aggregate approach" where a CMS was computed for every combination of earthquake rupture and GMM in the PSHA and then weighted subsequently.
TARGET OUTCOMES.
- (i) Revive the "exact" CMS tool as described in Lin et al. 2013;
- (ii) include conditional covariance that was also described in Lin et al. 2013 but was not in previous USGS tool; and
- (iii) include vertical (V) components of GM. When available, means, standard deviations, and correlations for V components can be used to determine CS for V components but when unavailable, they can be derived from GMMs for V/H ratios.
USE CASE. The "exact" multicomponent CS can be used in external software (e.g., Prof. Baker's Matlab code) to select multicomponent GMs, which can then be used to conduct dynamic structural analyses and assess seismic risk.
Activity
added Enhancement New Feature labels
Related: nshmp-haz#216 (Issue dates to before separation of nshmp-haz and nshmp-lib)
Edited by Powers, Peter M.mentioned in issue nshmp-haz#216
