Model Changes

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Peter Powers edited this page Dec 2, 2016 · 1 revision

This page documents known implementation differences between nshmp-haz, USGS Fortran codes, and OpenSHA.

NGA Focal Mechanism Flags: Whereas BA 2008 and other models accepted double values for focal mechanism weights (f_s, f_r, f_n, f_u), their intended use was for only 1 to be set to 1 and the rest to 0. The 2008 fortran codes supplied fractions (e.g. f_s=0.5 and f_r=0.5). The current code treated each focal mechanism type independently and then added the weighted hazard curves. This was corrected in 2014 nshm fortran code, but nshmp-haz behavior remains inconsistent with 2008 Fortran behavior.

U.S. Geological Survey – National Seismic Hazard Mapping Project (NSHMP)