Source code for openquake.hazardlib.gsim.bommer_2009

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Copyright (C) 2013-2023 GEM Foundation
#
# OpenQuake is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# OpenQuake is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with OpenQuake. If not, see <http://www.gnu.org/licenses/>.

"""
Module exports :class:`BommerEtAl2009RSD`
"""
import numpy as np

from openquake.hazardlib.gsim.base import CoeffsTable, GMPE
from openquake.hazardlib import const
from openquake.hazardlib.imt import RSD595, RSD575


def get_magnitude_term(C, mag):
    """
    Returns linear magnitude scaling term
    """
    return C["c0"] + C["m1"] * mag


def get_distance_term(C, rrup, mag):
    """
    Returns distance scaling term
    """
    return (C["r1"] + C["r2"] * mag) *\
        np.log(np.sqrt(rrup ** 2. + C["h1"] ** 2.))


def get_ztor_term(C, ztor):
    """
    Returns depth to top of rupture scaling
    """
    return C["z1"] * ztor


def get_site_amplification(C, vs30):
    """
    Returns linear site amplification term
    """
    return C["v1"] * np.log(vs30)


def get_stddevs(C):
    """
    Returns the standard deviations
    """
    return [np.sqrt(C["tau"] ** 2. + C["phi"] ** 2.), C["tau"], C["phi"]]


class BommerEtAl2009RSD(GMPE):
    """
    Implements the GMPE of Bommer et al. (2009) for significant duration with
    5 - 75 % Arias Intensity and 5 - 95 % Arias Intensity
    """
    #: Supported tectonic region type is active shallow crust
    DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.ACTIVE_SHALLOW_CRUST

    #: Supported intensity measure types are 5 - 95 % Arias and 5 - 75 % Arias
    #: significant duration
    DEFINED_FOR_INTENSITY_MEASURE_TYPES = {RSD595, RSD575}

    #: Supported intensity measure component is the geometric mean horizontal
    #: component
    DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.GEOMETRIC_MEAN

    #: Supported standard deviation type is only total, see table 7, page 35
    DEFINED_FOR_STANDARD_DEVIATION_TYPES = {
        const.StdDev.TOTAL, const.StdDev.INTER_EVENT, const.StdDev.INTRA_EVENT}

    #: Requires vs30
    REQUIRES_SITES_PARAMETERS = {'vs30'}

    #: Required rupture parameters are magnitude and top of rupture depth
    REQUIRES_RUPTURE_PARAMETERS = {'mag', 'ztor'}

    #: Required distance measure is closest distance to rupture
    REQUIRES_DISTANCES = {'rrup'}

    def compute(self, ctx: np.recarray, imts, mean, sig, tau, phi):
        """
        See :meth:`superclass method
        <.base.GroundShakingIntensityModel.compute>`
        for spec of input and result values.
        """
        for m, imt in enumerate(imts):
            C = self.COEFFS[imt]
            mean[m] = (get_magnitude_term(C, ctx.mag) +
                       get_distance_term(C, ctx.rrup, ctx.mag) +
                       get_ztor_term(C, ctx.ztor) +
                       get_site_amplification(C, ctx.vs30))

            sig[m], tau[m], phi[m] = get_stddevs(C)

    COEFFS = CoeffsTable(sa_damping=5, table="""\
    imt          c0       m1      r1       r2      h1       v1       z1     tau     phi
    rsd575  -5.6298   1.2619  2.0063  -0.2520  2.3316  -0.2900  -0.0522  0.3527  0.4304
    rsd595  -2.2393   0.9368  1.5686  -0.1953  2.5000  -0.3478  -0.0365  0.3252  0.3460
    """)