Implements GMPE developed by Walter Silva, Nick Gregor and Robert Darragh and documented in “Development of regional hard rock attenuation relations for central and eastern north America” (2002). Document available at: http://pbadupws.nrc.gov/docs/ML0423/ML042310569.pdf
This class replicates the algorithm as coded in the subroutine getSilva in the hazgridXnga2.f Fortran code available at: http://earthquake.usgs.gov/hazards/products/conterminous/2008/software/
The class assumes rupture magnitude to be in Mblg scale (given that MFDs for central and eastern US are given in this scale). Therefore Mblg is converted to Mw using the Atkinson & Boore 1987 conversion equation.
Coefficients are given for the B/C site conditions.
Coefficient table obtained from coefficient arrays (c1, c2, c4, c6, c7, c10, sigma) defined in suroutine getSilva in hazgridXnga2.f
Supported intensity measure component is the average horizontal component
Supported intensity measure types are spectral acceleration, and peak ground acceleration
Supported standard deviation type is only total.
Supported tectonic region type is stable continental crust, given that the equations have been derived for central and eastern north America
Required distance measure is rjb
Required rupture parameter is only magnitude (Mblg).
No site parameters required
Extend SilvaEtAl2002MblgAB1987NSHMP2008 but uses Johnston 1996 equation for converting Mblg to Mw.