Source code for openquake.hazardlib.gsim.mgmpe.nrcan15_site_term

# The Hazard Library
# Copyright (C) 2012-2020 GEM Foundation
#
# This program 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.
#
# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Module :mod:`openquake.hazardlib.mgmp.nrcan15_site_term` implements
:class:`~openquake.hazardlib.mgmpe.NRCan15SiteTerm`
"""

import copy
import numpy as np
from openquake.hazardlib import const
from openquake.hazardlib.gsim.base import CoeffsTable
from openquake.hazardlib.gsim.base import GMPE, registry
from openquake.hazardlib.gsim.boore_atkinson_2008 import BooreAtkinson2008


[docs]class NRCan15SiteTerm(GMPE): """ Implements a modified GMPE class that can be used to account for local soil conditions in the estimation of ground motion. :param gmpe_name: The name of a GMPE class """ # Parameters REQUIRES_SITES_PARAMETERS = {'vs30'} REQUIRES_DISTANCES = set() REQUIRES_RUPTURE_PARAMETERS = set() DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = '' DEFINED_FOR_INTENSITY_MEASURE_TYPES = set() DEFINED_FOR_STANDARD_DEVIATION_TYPES = {const.StdDev.TOTAL} DEFINED_FOR_TECTONIC_REGION_TYPE = '' DEFINED_FOR_REFERENCE_VELOCITY = None def __init__(self, gmpe_name): super().__init__(gmpe_name=gmpe_name) self.gmpe = registry[gmpe_name]() self.set_parameters() # # Check if this GMPE has the necessary requirements if not (hasattr(self.gmpe, 'DEFINED_FOR_REFERENCE_VELOCITY') or 'vs30' in self.gmpe.REQUIRES_SITES_PARAMETERS): msg = '{:s} does not use vs30 nor a defined reference velocity' raise AttributeError(msg.format(str(self.gmpe))) if 'vs30' not in self.gmpe.REQUIRES_SITES_PARAMETERS: self.REQUIRES_SITES_PARAMETERS = frozenset( self.gmpe.REQUIRES_SITES_PARAMETERS | {'vs30'}) # # Check compatibility of reference velocity if hasattr(self.gmpe, 'DEFINED_FOR_REFERENCE_VELOCITY'): assert (self.gmpe.DEFINED_FOR_REFERENCE_VELOCITY >= 760 and self.gmpe.DEFINED_FOR_REFERENCE_VELOCITY <= 800)
[docs] def get_mean_and_stddevs(self, sites, rup, dists, imt, stds_types): """ See :meth:`superclass method <.base.GroundShakingIntensityModel.get_mean_and_stddevs>` for spec of input and result values. """ # Prepare sites sites_rock = copy.copy(sites) sites_rock.vs30 = np.ones_like(sites_rock.vs30) * 760. # compute mean and standard deviation mean, stddvs = self.gmpe.get_mean_and_stddevs(sites_rock, rup, dists, imt, stds_types) if not str(imt) == 'PGA': # compute mean and standard deviation on rock mean_rock, stddvs_rock = self.gmpe.get_mean_and_stddevs( sites_rock, rup, dists, imt, stds_types) else: mean_rock = mean fa = self.BA08_AB06(sites.vs30, imt, np.exp(mean_rock)) mean = np.log(np.exp(mean) * fa) return mean, stddvs
[docs] def BA08_AB06(self, vs30, imt, pgar): """ Computes amplification factor similarly to what is done in the 2015 version of the Canada building code. An initial version of this code was kindly provided by Michal Kolaj - Geological Survey of Canada :param vs30: Can be either a scalar or a :class:`~numpy.ndarray` instance :param imt: The intensity measure type :param pgar: The value of hazard on rock (vs30=760). Can be either a scalar or a :class:`~numpy.ndarray` instance. Unit of measure is fractions of gravity acceleration. :return: A scalar or a :class:`~numpy.ndarray` instance with the amplification factor. """ fa = np.ones_like(vs30) if np.isscalar(vs30): vs30 = np.array([vs30]) if np.isscalar(pgar): pgar = np.array([pgar]) # # Fixing vs30 for hard rock to 1999 m/s. Beyond this threshold the # motion will not be deamplified further vs = copy.copy(vs30) vs[vs >= 2000] = 1999. # # Computing motion on rock idx = np.where(vs30 > 760) if np.size(idx) > 0: """ # This is the original implementation - Since this code is # experimental we keep it for possible further developments # For values of Vs30 greater than 760 a linear interpolation is # used between the gm factor at 2000 m/s and 760 m/s C2 = self.COEFFS_AB06r[imt] fa[idx] = 10**(np.interp(np.log10(vs[idx]), np.log10([760.0, 2000.0]), np.log10([1.0, C2['c']]))) """ C = self.COEFFS_BA08[imt] nl = BooreAtkinson2008()._get_site_amplification_non_linear( vs[idx], pgar[idx], C) lin = BooreAtkinson2008()._get_site_amplification_linear( vs[idx], C) tmp = np.exp(nl+lin) fa[idx] = tmp # # For values of Vs30 lower than 760 the amplification is computed # using the site term of Boore and Atkinson (2008) idx = np.where(vs < 760.) if np.size(idx) > 0: C = self.COEFFS_BA08[imt] nl = BooreAtkinson2008()._get_site_amplification_non_linear( vs[idx], pgar[idx], C) lin = BooreAtkinson2008()._get_site_amplification_linear( vs[idx], C) fa[idx] = np.exp(nl+lin) return fa
COEFFS_AB06r = CoeffsTable(sa_damping=5, table="""\ IMT c pgv 1.230 pga 0.891 0.05 0.891 0.10 1.072 0.20 1.318 0.30 1.380 0.50 1.380 1.00 1.288 2.00 1.230 5.00 1.148 10.0 1.072 """) COEFFS_BA08 = CoeffsTable(sa_damping=5, table="""\ IMT blin b1 b2 pgv -0.60 -0.50 -0.06 pga -0.36 -0.64 -0.14 0.010 -0.36 -0.64 -0.14 0.020 -0.34 -0.63 -0.12 0.030 -0.33 -0.62 -0.11 0.040 -0.31 -0.61 -0.11 0.050 -0.29 -0.64 -0.11 0.060 -0.25 -0.64 -0.11 0.075 -0.23 -0.64 -0.11 0.090 -0.23 -0.64 -0.12 0.100 -0.25 -0.60 -0.13 0.120 -0.26 -0.56 -0.14 0.150 -0.28 -0.53 -0.18 0.170 -0.29 -0.53 -0.19 0.200 -0.31 -0.52 -0.19 0.240 -0.38 -0.52 -0.16 0.250 -0.39 -0.52 -0.16 0.300 -0.44 -0.52 -0.14 0.360 -0.48 -0.51 -0.11 0.400 -0.50 -0.51 -0.10 0.460 -0.55 -0.50 -0.08 0.500 -0.60 -0.50 -0.06 0.600 -0.66 -0.49 -0.03 0.750 -0.69 -0.47 -0.00 0.850 -0.69 -0.46 -0.00 1.000 -0.70 -0.44 -0.00 1.500 -0.72 -0.40 -0.00 2.000 -0.73 -0.38 -0.00 3.000 -0.74 -0.34 -0.00 4.000 -0.75 -0.31 -0.00 5.000 -0.75 -0.291 -0.00 7.500 -0.692 -0.247 -0.00 10.00 -0.650 -0.215 -0.00 """)