Implements GMPE developed by N. A. Abrahamson and W. J. Silva and published as “Empirical Response Spectral Attenuation Relations for Shallow Crustal Earthquakes”, Seismological Research Letters, v.68, no. 1, p. 94-127, 1997.
The GMPE distinguishes between rock (vs30 >= 600) and deep soil (vs30 < 600). The rake angle is also taken into account to distinguish between ‘reverse’ (45 <= rake < 135) and ‘other’. If an earthquake rupture is classified as ‘reverse’, then the hanging-wall term is included in the mean calculation.
Coefficient table (table 3, page 108)
Coefficient table for standard deviation calculation (table 4, page 109)
Supported intensity measure component is the geometric mean of two horizontal components (see paragraph ‘Regression Model’, page 105)
Supported intensity measure types are PGA and SA. PGA is assumed to have same coefficients as SA(0.01)
Supported standard deviation type is Total (see equations 13 pp. 106 and table 4, page 109).
Supported tectonic region type is ‘active shallow crust’ (see Introduction, page 94)
Required distance measure is RRup (eq. 3, page 105).
Required rupture parameters are magnitude, and rake (eq. 3, page 105). Rake is used to distinguish between ‘reverse’ (45 <= rake <= 135) and ‘other’ (i.e. strike-slip and normal). If an earthquake is classified as ‘reverse’ than the hanging-wall term is taken into account.
The only site parameter is vs30 used to distinguish between rock (vs30 > 600 m/s) and deep soil (see table 2, page 95)