@Beta public abstract class NgaEastUsgs_2017 extends Object implements GroundMotionModel
Calculation of hazard using this implementation deviates somewhat from the
current nshmp-haz PSHA pipeline and required implementation of a
MultiScalarGroundMotion. A MultiScalarGroundMotion stores
arrays of means and sigmas with associated weights.
This class also manages implementations of 22 'seed' models, 19 of which were used to generate (via Sammons mapping) the 17 NGA-East for USGS models and associated weights, and 3 of which are updates. This class also handles USGS logic tree of 14 of those seed models. Ground motions for most models are computed via table lookups (SP16 is the exception).
On it's own, NGA-East is a hard rock model returning results for a site class where Vs30 = 3000 m/s. To accomodate other site classes, the Stewart et al. (2017) CEUS site amplification model is used. This model is applicable to 200 ≤ vs30 ≤ 2000 m/s. In the current implementation, for vs30 < 200, vs30 = 200 m/s; for vs30 > 2000, vs30 = 3000 m/s.
Note: Direct instantiation of GroundMotionModels is
prohibited. Use Gmm.instance(Imt) to retrieve an instance for a
desired Imt.
Implementation note: Mean values are NOT clamped per
GmmUtils.ceusMeanClip(Imt, double).
Reference: Goulet, C., Bozorgnia, Y., Kuehn, N., Al Atik L., Youngs, R., Graves, R., Atkinson, G., 2017, NGA-East ground-motion models for the U.S. Geological Survey national seismic hazard maps: PEER Report No. 2017/03, 180 p.
Reference: Stewart, J., Parker, G., Harmon, J., Atkinson, G., Boore, D., Darragh, R., Silva, W., and Hashash, Y., 2017, Expert panel recommendations for ergodic site amplification in central and eastern North America: PEER Report No. 2017/04, 66 p.
Reference: Hashash, Y., Harmon, J., Ilhan, O., Parker, G., and Stewart, 2017, Recommendation for ergodic nonlinear site amplification in central and eastern North America: PEER Report No. 2017/05, 62 p.
Component: average horizontal (RotD50)