Source code for openquake.hazardlib.gsim.geomatrix_1993

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"""
Module exports :class:`Geomatrix1993SSlabNSHMP2008`.
"""
from __future__ import division

import numpy as np

from openquake.hazardlib.gsim.base import CoeffsTable, GMPE
from openquake.hazardlib import const
from openquake.hazardlib.imt import PGA, SA


[docs]class Geomatrix1993SSlabNSHMP2008(GMPE): """ Implements GMPE for subduction intraslab events developed by Geomatrix Consultants, Inc., 1993, "Seismic margin earthquake for the Trojan site: Final unpublished report prepared for Portland General Electric Trojan Nuclear Plant", Ranier, Oregon. This class implements the equation as coded in the subroutine ``getGeom`` in the ``hazgridXnga2.f`` Fortran code available at: http://earthquake.usgs.gov/hazards/products/conterminous/2008/software/ Coefficients are given for the B/C site conditions. """ #: Supported tectonic region type is subduction intraslab DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.SUBDUCTION_INTRASLAB #: Supported intensity measure types are spectral acceleration, #: and peak ground acceleration DEFINED_FOR_INTENSITY_MEASURE_TYPES = set([ PGA, SA ]) #: Supported intensity measure component is the geometric mean of #: two horizontal components DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.AVERAGE_HORIZONTAL #: Supported standard deviation type is only total. DEFINED_FOR_STANDARD_DEVIATION_TYPES = set([ const.StdDev.TOTAL ]) #: No site parameters required REQUIRES_SITES_PARAMETERS = set() #: Required rupture parameters are magnitude and top of rupture depth REQUIRES_RUPTURE_PARAMETERS = set(('mag', 'ztor')) #: Required distance measure is rrup (closest distance to rupture) REQUIRES_DISTANCES = set(('rrup', ))
[docs] def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types): """ See :meth:`superclass method <.base.GroundShakingIntensityModel.get_mean_and_stddevs>` for spec of input and result values. """ assert all(stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES for stddev_type in stddev_types) C = self.COEFFS[imt] mean = self._compute_mean(C, rup.mag, rup.ztor, dists.rrup) stddevs = self._compute_stddevs( C, rup.mag, dists.rrup.shape, stddev_types ) return mean, stddevs
def _compute_mean(self, C, mag, ztor, rrup): """ Compute mean value as in ``subroutine getGeom`` in ``hazgridXnga2.f`` """ gc0 = 0.2418 ci = 0.3846 gch = 0.00607 g4 = 1.7818 ge = 0.554 gm = 1.414 mean = ( gc0 + ci + ztor * gch + C['gc1'] + gm * mag + C['gc2'] * (10 - mag) ** 3 + C['gc3'] * np.log(rrup + g4 * np.exp(ge * mag)) ) return mean def _compute_stddevs(self, C, mag, num_sites, stddev_types): """ Return total standard deviation. """ std_total = C['gc4'] + C['gc5'] * np.minimum(8., mag) stddevs = [] for _ in stddev_types: stddevs.append(np.zeros(num_sites) + std_total) return stddevs #: Coefficient table obtained from coefficient arrays and variables #: defined in subroutine getGeom in hazgridXnga2.f COEFFS = CoeffsTable(sa_damping=5, table="""\ IMT gc1 gc2 gc3 gc4 gc5 pga 0.0 0.0 -2.556 1.45 -0.1 0.1 1.1880 -0.0011 -2.6550 1.45 -0.1 0.2 0.722 -0.0027 -2.528 1.45 -0.1 0.3 0.246 -0.0036 -2.454 1.45 -0.1 0.5 -0.4 -0.0048 -2.36 1.45 -0.1 1.0 -1.736 -0.0064 -2.234 1.45 -0.1 2.0 -3.3280 -0.0080 -2.107 1.55 -0.1 3.0 -4.511 -0.0089 -2.033 1.65 -0.1 """)