@@ -66,6 +66,41 @@ See the *nshmp-haz* user guide [site specification section][4] for more details
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@@ -66,6 +66,41 @@ See the *nshmp-haz* user guide [site specification section][4] for more details
**Suggested citation:** TBD.
**Suggested citation:** TBD.
### 2007 Implementation Details (from xml repo v2.1.2; TODO clean)
Notable implementation details (in fortran source and inputs) that set Alaska 2007 apart from
later COUS models and this updated nshmp-haz implementation of the Alaska model:
* Grid and slab optimization tables use discretization of 2km out to 200km.
* nshmp-haz: __discretization = 1km__
* Grid and slab sources use the Wells & Coppersmith (1994) magnitude-length scaling relation.
* nshmp-haz: __slab sources use Youngs et al. (1997)__ (aka 'geomatrix'; consistent with 2014
COUS NSHM)
* Grid and slab sources randomize strike at M≥6.
* nshmp-haz: __uses point-source distance corrections for M≥6__ (in relations above; consistent
with 2014 COUS NSHM)
* Ground motion models do not impose one-sided 3σ upper truncation on exceedances.
* nshmp-haz: __no change__
* Other details:
* nshmp-haz: __grid source maxDepth = 15 km__
* Focal mechansim variations are encoded into coefficients supplied with each input file; flavors
for strike-slip and mixed strike-slip/reverse were ported from the 2002 COUS model.
* nshmp-haz: __point sources generate focal mechanism specific ruptures with appropriate rake
that are processed independently, consistent with 2014 COUS NSHM__
* Aleatory uncertainty was added in the 2002 COUS model and was carried over here as a
moment-balanced Gaussian distribution on mMax of M±0.15 discretized over 5 values with σ=0.12.
The 2008 COUS model increased the width of the distribution to M±2σ and increased the
discretization to 11 values. Both implementations require custom code; the more recent approach
is more straightforward with the distribution a function of σ.
* nshmp-haz: __uses more recent (11-point; ±2σ) aleatory uncertainty model__
* Hazard curves are not truncated at 3σ.
* nshmp-haz: __no change__
### 2007 Other Notes (from xml repo v2.1.2; TODO clean)
* Consistent with 2008 and 2014 COUS models, slab and grid Gutenberg-Richter MFD magnitudes bins are centered on 0.05; interface MFD bins are centered on 0.1.
