Abrahamson and Silva 2008

class openquake.hazardlib.gsim.abrahamson_silva_2008.AbrahamsonSilva2008[source]

Implements GMPE developed by Norman Abrahamson and Walter Silva and published as “Summary of the Abrahamson & Silva NGA Ground-Motion Relations” (2008, Earthquakes Spectra, Volume 24, Number 1, pages 67-97). This class implements only the equations for mainshock/foreshocks/swarms type events, that is the aftershock term (4th term in equation 1, page 74) is set to zero. The constant displacement model (page 80) is also not implemented (that is equation 1, page 74 is used for all periods and no correction is applied for periods greater than the constant displacement period). This class implements also the corrections (for standard deviation and hanging wall term calculation) as described in: http://peer.berkeley.edu/products/abrahamson-silva_nga_report_files/ AS08_NGA_errata.pdf

COEFFS = <openquake.hazardlib.gsim.base.CoeffsTable object>

Coefficient tables obtained by joining table 5a page 84, and table 5b page 85.

CONSTS = {'a3': 0.265, 'a5': -0.398, 'a4': -0.231, 'sigma_amp': 0.3, 'c2': 50, 'c1': 6.75, 'n': 1.18, 'c': 1.88, 'c4': 4.5}

equation constants (that are IMT independent)


Supported intensity measure component is orientation-independent average horizontal GMRotI50, see abstract, page 67.

DEFINED_FOR_INTENSITY_MEASURE_TYPES = set([<class 'openquake.hazardlib.imt.PGA'>, <class 'openquake.hazardlib.imt.SA'>, <class 'openquake.hazardlib.imt.PGV'>])

Supported intensity measure types are spectral acceleration, peak ground velocity and peak ground acceleration, see tables 5a and 5b pages 84, 85, respectively.

DEFINED_FOR_STANDARD_DEVIATION_TYPES = set(['Total', 'Inter event', 'Intra event'])

Supported standard deviation types are inter-event, intra-event and total, see paragraph “Equations for standard deviations”, page 81.


Supported tectonic region type is active shallow crust, see paragraph ‘Data Set Selection’, see page 68.

REQUIRES_DISTANCES = set(['rx', 'rjb', 'rrup'])

Required distance measures are Rrup, Rjb and Rx (see Table 2, page 75).

REQUIRES_RUPTURE_PARAMETERS = set(['width', 'rake', 'dip', 'ztor', 'mag'])

Required rupture parameters are magnitude, rake, dip, ztor, and width (see table 2, page 75)

REQUIRES_SITES_PARAMETERS = set(['vs30measured', 'z1pt0', 'vs30'])

Required site parameters are Vs30, Vs30 type (measured or inferred), and Z1.0, see paragraph ‘Soil Depth Model’, page 79, and table 6, page 86.

get_mean_and_stddevs(sites, rup, dists, imt, stddev_types)[source]

See superclass method for spec of input and result values.