Source code for openquake.hazardlib.gsim.abrahamson_2015

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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"""
Module exports :class:`AbrahamsonEtAl2015`
               :class:`AbrahamsonEtAl2015SInter`
               :class:`AbrahamsonEtAl2015SInterHigh`
               :class:`AbrahamsonEtAl2015SInterLow`
               :class:`AbrahamsonEtAl2015SSlab`
               :class:`AbrahamsonEtAl2015SSlabHigh`
               :class:`AbrahamsonEtAl2015SSlabLow`

"""
import numpy as np

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

# Period-Independent Coefficients (Table 2)
CONSTS = {
    'n': 1.18,
    'c': 1.88,
    'theta3': 0.1,
    'theta4': 0.9,
    'theta5': 0.0,
    'theta9': 0.4,
    'c4': 10.0,
    'C1': 7.8
}

C1 = 7.2  # for Montalva2017

# Total epistemic uncertainty factors from Abrahamson et al. (2018)
BCHYDRO_SIGMA_MU = CoeffsTable(sa_damping=5, table="""
    imt     SIGMA_MU_SINTER    SIGMA_MU_SSLAB
    pga                 0.3              0.50
    0.010               0.3              0.50
    0.020               0.3              0.50
    0.030               0.3              0.50
    0.050               0.3              0.50
    0.075               0.3              0.50
    0.100               0.3              0.50
    0.150               0.3              0.50
    0.200               0.3              0.50
    0.250               0.3              0.46
    0.300               0.3              0.42
    0.400               0.3              0.38
    0.500               0.3              0.34
    0.600               0.3              0.30
    0.750               0.3              0.30
    1.000               0.3              0.30
    1.500               0.3              0.30
    2.000               0.3              0.30
    2.500               0.3              0.30
    3.000               0.3              0.30
    4.000               0.3              0.30
    5.000               0.3              0.30
    6.000               0.3              0.30
    7.500               0.3              0.30
    10.00               0.3              0.30
    """)


[docs]def get_stress_factor(imt, slab): """ Returns the stress adjustment factor for the BC Hydro GMPE according to Abrahamson et al. (2018) """ C = BCHYDRO_SIGMA_MU[imt] return (C["SIGMA_MU_SSLAB"] if slab else C["SIGMA_MU_SINTER"]) / 1.65
def _compute_magterm(C1, theta1, theta4, theta5, theta13, dc1, mag): """ Computes the magnitude scaling term given by equation (2) corrected by a local adjustment factor """ base = theta1 + theta4 * dc1 dmag = C1 + dc1 f_mag = np.where( mag > dmag, theta5 * (mag - dmag), theta4 * (mag - dmag)) return base + f_mag + theta13 * (10. - mag) ** 2. # theta6_adj used in BCHydro def _compute_disterm(trt, C1, theta2, theta14, theta3, ctx, c4, theta9, theta6_adj, theta6, theta10): if trt == const.TRT.SUBDUCTION_INTERFACE: dists = ctx.rrup assert theta10 == 0., theta10 elif trt == const.TRT.SUBDUCTION_INTRASLAB: dists = ctx.rhypo else: raise NotImplementedError(trt) return (theta2 + theta14 + theta3 * (ctx.mag - C1)) * np.log( dists + c4 * np.exp((ctx.mag - 6.) * theta9)) + ( theta6_adj + theta6) * dists + theta10 def _compute_forearc_backarc_term(trt, faba_model, C, ctx): if trt == const.TRT.SUBDUCTION_INTERFACE: dists = ctx.rrup a, b = C['theta15'], C['theta16'] min_dist = 100. elif trt == const.TRT.SUBDUCTION_INTRASLAB: dists = ctx.rhypo a, b = C['theta7'], C['theta8'] min_dist = 85. else: raise NotImplementedError(trt) if faba_model is None: backarc = np.bool_(ctx.backarc) f_faba = np.zeros_like(dists) # Term only applies to backarc ctx (F_FABA = 0. for forearc) fixed_dists = dists[backarc] fixed_dists[fixed_dists < min_dist] = min_dist f_faba[backarc] = a + b * np.log(fixed_dists / 40.) return f_faba # in BCHydro subclasses fixed_dists = np.copy(dists) fixed_dists[fixed_dists < min_dist] = min_dist f_faba = a + b * np.log(fixed_dists / 40.) return f_faba * faba_model(-ctx.xvf) def _compute_distance_term(kind, trt, theta6_adj, C, ctx): """ Computes the distance scaling term, as contained within equation (1) """ if kind.startswith("montalva"): theta3 = C['theta3'] else: theta3 = CONSTS['theta3'] if kind == "montalva17": C1 = 7.2 else: C1 = 7.8 if trt == const.TRT.SUBDUCTION_INTERFACE: return _compute_disterm( trt, C1, C['theta2'], 0., theta3, ctx, CONSTS['c4'], CONSTS['theta9'], theta6_adj, C['theta6'], theta10=0.) else: # sslab return _compute_disterm( trt, C1, C['theta2'], C['theta14'], theta3, ctx, CONSTS['c4'], CONSTS['theta9'], theta6_adj, C['theta6'], C["theta10"]) def _compute_focal_depth_term(trt, C, ctx): """ Computes the hypocentral depth scaling term - as indicated by equation (3) For interface events F_EVENT = 0.. so no depth scaling is returned. For SSlab events computes the hypocentral depth scaling term as indicated by equation (3) """ if trt == const.TRT.SUBDUCTION_INTERFACE: return np.zeros_like(ctx.mag) z_h = np.clip(ctx.hypo_depth, None, 120.) return C['theta11'] * (z_h - 60.) def _compute_magnitude_term(kind, C, dc1, mag): """ Computes the magnitude scaling term given by equation (2) """ if kind == "base": return _compute_magterm( CONSTS['C1'], C['theta1'], CONSTS['theta4'], CONSTS['theta5'], C['theta13'], dc1, mag) elif kind == "montalva16": return _compute_magterm( CONSTS['C1'], C['theta1'], C['theta4'], C['theta5'], C['theta13'], dc1, mag) elif kind == "montalva17": return _compute_magterm(C1, C['theta1'], C['theta4'], C['theta5'], 0., dc1, mag) def _compute_pga_rock(kind, trt, theta6_adj, faba_model, C, dc1, ctx): """ Compute and return mean imt value for rock conditions (vs30 = 1000 m/s) """ mean = (_compute_magnitude_term(kind, C, dc1, ctx.mag) + _compute_distance_term(kind, trt, theta6_adj, C, ctx) + _compute_focal_depth_term(trt, C, ctx) + _compute_forearc_backarc_term(trt, faba_model, C, ctx)) # Apply linear site term site_response = ((C['theta12'] + C['b'] * CONSTS['n']) * np.log(1000. / C['vlin'])) return mean + site_response def _compute_site_response_term(C, ctx, pga1000): """ Compute and return site response model term This GMPE adopts the same site response scaling model of Walling et al (2008) as implemented in the Abrahamson & Silva (2008) GMPE. The functional form is retained here. """ vs_star = ctx.vs30.copy() vs_star[vs_star > 1000.0] = 1000. arg = vs_star / C["vlin"] site_resp_term = C["theta12"] * np.log(arg) # Get linear scaling term idx = ctx.vs30 >= C["vlin"] site_resp_term[idx] += (C["b"] * CONSTS["n"] * np.log(arg[idx])) # Get nonlinear scaling term idx = np.logical_not(idx) site_resp_term[idx] += ( -C["b"] * np.log(pga1000[idx] + CONSTS["c"]) + C["b"] * np.log(pga1000[idx] + CONSTS["c"] * (arg[idx] ** CONSTS["n"]))) return site_resp_term
[docs]class AbrahamsonEtAl2015SInter(GMPE): """ Implements the Subduction GMPE developed by Norman Abrahamson, Nicholas Gregor and Kofi Addo, otherwise known as the "BC Hydro" Model, published as "BC Hydro Ground Motion Prediction Equations For Subduction Earthquakes (2015, Earthquake Spectra, in press), for subduction interface events. From observations of very large events it was found that the magnitude scaling term can be adjusted as part of the epistemic uncertainty model. The adjustment comes in the form of the parameter DeltaC1, which is period dependent for interface events. To capture the epistemic uncertainty in DeltaC1, three models are proposed: a 'central', 'upper' and 'lower' model. The current class implements the 'central' model, whilst additional classes will implement the 'upper' and 'lower' alternatives. """ #: Supported tectonic region type is subduction interface DEFINED_FOR_TECTONIC_REGION_TYPE = trt = const.TRT.SUBDUCTION_INTERFACE #: Supported intensity measure types are spectral acceleration, #: and peak ground acceleration DEFINED_FOR_INTENSITY_MEASURE_TYPES = {PGA, SA} #: Supported intensity measure component is the geometric mean component DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.AVERAGE_HORIZONTAL #: Supported standard deviation types are inter-event, intra-event #: and total, see table 3, pages 12 - 13 DEFINED_FOR_STANDARD_DEVIATION_TYPES = { const.StdDev.TOTAL, const.StdDev.INTER_EVENT, const.StdDev.INTRA_EVENT} #: Site amplification is dependent upon Vs30 #: For the Abrahamson et al (2013) GMPE a new term is introduced to #: determine whether a site is on the forearc with respect to the #: subduction interface, or on the backarc. This boolean is a vector #: containing True for a backarc site or False for a forearc or #: unknown site. REQUIRES_SITES_PARAMETERS = {'vs30', 'backarc'} #: Required rupture parameters are magnitude for the interface model REQUIRES_RUPTURE_PARAMETERS = {'mag'} #: Required distance measure is closest distance to rupture, for #: interface events REQUIRES_DISTANCES = {'rrup'} #: Reference soil conditions (bottom of page 29) DEFINED_FOR_REFERENCE_VELOCITY = 1000 delta_c1 = None kind = "base" FABA_ALL_MODELS = {} # overridden in BCHydro def __init__(self, **kwargs): super().__init__(**kwargs) self.ergodic = kwargs.get('ergodic', True) self.theta6_adj = kwargs.get("theta6_adjustment", 0.0) self.sigma_mu_epsilon = kwargs.get("sigma_mu_epsilon", 0.0) faba_type = kwargs.get("faba_taper_model", "Step") if 'xvf' in self.REQUIRES_SITES_PARAMETERS: # BCHydro subclasses self.faba_model = self.FABA_ALL_MODELS[faba_type](**kwargs) else: self.faba_model = None
[docs] 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. """ C_PGA = self.COEFFS[PGA()] dc1_pga = self.delta_c1 or self.COEFFS_MAG_SCALE[PGA()]["dc1"] # compute median pga on rock (vs30=1000), needed for site response # term calculation pga1000 = np.exp(_compute_pga_rock( self.kind, self.trt, self.theta6_adj, self.faba_model, C_PGA, dc1_pga, ctx)) for m, imt in enumerate(imts): C = self.COEFFS[imt] dc1 = self.delta_c1 or self.COEFFS_MAG_SCALE[imt]["dc1"] mean[m] = ( _compute_magnitude_term( self.kind, C, dc1, ctx.mag) + _compute_distance_term( self.kind, self.trt, self.theta6_adj, C, ctx) + _compute_focal_depth_term( self.trt, C, ctx) + _compute_forearc_backarc_term( self.trt, self.faba_model, C, ctx) + _compute_site_response_term( C, ctx, pga1000)) if self.sigma_mu_epsilon: sigma_mu = get_stress_factor( imt, self.DEFINED_FOR_TECTONIC_REGION_TYPE == const.TRT.SUBDUCTION_INTRASLAB) mean[m] += sigma_mu * self.sigma_mu_epsilon sig[m] = C["sigma"] if self.ergodic else C["sigma_ss"] tau[m] = C['tau'] phi[m] = C["phi"] if self.ergodic else np.sqrt( C["sigma_ss"] ** 2. - C["tau"] ** 2.)
# Period-dependent coefficients (Table 3) COEFFS = CoeffsTable(sa_damping=5, table="""\ imt vlin b theta1 theta2 theta6 theta7 theta8 theta10 theta11 theta12 theta13 theta14 theta15 theta16 phi tau sigma sigma_ss pga 865.1000 -1.1860 4.2203 -1.3500 -0.0012 1.0988 -1.4200 3.1200 0.0130 0.9800 -0.0135 -0.4000 0.9969 -1.0000 0.6000 0.4300 0.7400 0.6000 0.0200 865.1000 -1.1860 4.2203 -1.3500 -0.0012 1.0988 -1.4200 3.1200 0.0130 0.9800 -0.0135 -0.4000 0.9969 -1.0000 0.6000 0.4300 0.7400 0.6000 0.0500 1053.5000 -1.3460 4.5371 -1.4000 -0.0012 1.2536 -1.6500 3.3700 0.0130 1.2880 -0.0138 -0.4000 1.1030 -1.1800 0.6000 0.4300 0.7400 0.6000 0.0750 1085.7000 -1.4710 5.0733 -1.4500 -0.0012 1.4175 -1.8000 3.3700 0.0130 1.4830 -0.0142 -0.4000 1.2732 -1.3600 0.6000 0.4300 0.7400 0.6000 0.1000 1032.5000 -1.6240 5.2892 -1.4500 -0.0012 1.3997 -1.8000 3.3300 0.0130 1.6130 -0.0145 -0.4000 1.3042 -1.3600 0.6000 0.4300 0.7400 0.6000 0.1500 877.6000 -1.9310 5.4563 -1.4500 -0.0014 1.3582 -1.6900 3.2500 0.0130 1.8820 -0.0153 -0.4000 1.2600 -1.3000 0.6000 0.4300 0.7400 0.6000 0.2000 748.2000 -2.1880 5.2684 -1.4000 -0.0018 1.1648 -1.4900 3.0300 0.0129 2.0760 -0.0162 -0.3500 1.2230 -1.2500 0.6000 0.4300 0.7400 0.6000 0.2500 654.3000 -2.3810 5.0594 -1.3500 -0.0023 0.9940 -1.3000 2.8000 0.0129 2.2480 -0.0172 -0.3100 1.1600 -1.1700 0.6000 0.4300 0.7400 0.6000 0.3000 587.1000 -2.5180 4.7945 -1.2800 -0.0027 0.8821 -1.1800 2.5900 0.0128 2.3480 -0.0183 -0.2800 1.0500 -1.0600 0.6000 0.4300 0.7400 0.6000 0.4000 503.0000 -2.6570 4.4644 -1.1800 -0.0035 0.7046 -0.9800 2.2000 0.0127 2.4270 -0.0206 -0.2300 0.8000 -0.7800 0.6000 0.4300 0.7400 0.6000 0.5000 456.6000 -2.6690 4.0181 -1.0800 -0.0044 0.5799 -0.8200 1.9200 0.0125 2.3990 -0.0231 -0.1900 0.6620 -0.6200 0.6000 0.4300 0.7400 0.6000 0.6000 430.3000 -2.5990 3.6055 -0.9900 -0.0050 0.5021 -0.7000 1.7000 0.0124 2.2730 -0.0256 -0.1600 0.5800 -0.5000 0.6000 0.4300 0.7400 0.6000 0.7500 410.5000 -2.4010 3.2174 -0.9100 -0.0058 0.3687 -0.5400 1.4200 0.0120 1.9930 -0.0296 -0.1200 0.4800 -0.3400 0.6000 0.4300 0.7400 0.6000 1.0000 400.0000 -1.9550 2.7981 -0.8500 -0.0062 0.1746 -0.3400 1.1000 0.0114 1.4700 -0.0363 -0.0700 0.3300 -0.1400 0.6000 0.4300 0.7400 0.6000 1.5000 400.0000 -1.0250 2.0123 -0.7700 -0.0064 -0.0820 -0.0500 0.7000 0.0100 0.4080 -0.0493 0.0000 0.3100 0.0000 0.6000 0.4300 0.7400 0.6000 2.0000 400.0000 -0.2990 1.4128 -0.7100 -0.0064 -0.2821 0.1200 0.7000 0.0085 -0.4010 -0.0610 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 2.5000 400.0000 0.0000 0.9976 -0.6700 -0.0064 -0.4108 0.2500 0.7000 0.0069 -0.7230 -0.0711 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 3.0000 400.0000 0.0000 0.6443 -0.6400 -0.0064 -0.4466 0.3000 0.7000 0.0054 -0.6730 -0.0798 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 4.0000 400.0000 0.0000 0.0657 -0.5800 -0.0064 -0.4344 0.3000 0.7000 0.0027 -0.6270 -0.0935 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 5.0000 400.0000 0.0000 -0.4624 -0.5400 -0.0064 -0.4368 0.3000 0.7000 0.0005 -0.5960 -0.0980 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 6.0000 400.0000 0.0000 -0.9809 -0.5000 -0.0064 -0.4586 0.3000 0.7000 -0.0013 -0.5660 -0.0980 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 7.5000 400.0000 0.0000 -1.6017 -0.4600 -0.0064 -0.4433 0.3000 0.7000 -0.0033 -0.5280 -0.0980 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 10.0000 400.0000 0.0000 -2.2937 -0.4000 -0.0064 -0.4828 0.3000 0.7000 -0.0060 -0.5040 -0.0980 0.0000 0.3000 0.0000 0.6000 0.4300 0.7400 0.6000 """) COEFFS_MAG_SCALE = CoeffsTable(sa_damping=5, table=""" IMT dc1 pga 0.2 0.02 0.2 0.30 0.2 0.50 0.1 1.00 0.0 2.00 -0.1 3.00 -0.2 10.0 -0.2 """)
[docs]class AbrahamsonEtAl2015SInterHigh(AbrahamsonEtAl2015SInter): """ Defines the Abrahamson et al. (2013) scaling relation assuming the upper values of the magnitude scaling for large slab earthquakes, as defined in table 4 """ COEFFS_MAG_SCALE = CoeffsTable(sa_damping=5, table=""" IMT dc1 pga 0.4 0.02 0.4 0.30 0.4 0.50 0.3 1.00 0.2 2.00 0.1 3.00 0.0 10.0 0.0 """)
[docs]class AbrahamsonEtAl2015SInterLow(AbrahamsonEtAl2015SInter): """ Defines the Abrahamson et al. (2013) scaling relation assuming the lower values of the magnitude scaling for large slab earthquakes, as defined in table 4 """ COEFFS_MAG_SCALE = CoeffsTable(sa_damping=5, table=""" IMT dc1 pga 0.0 0.02 0.0 0.30 0.0 0.50 -0.1 1.00 -0.2 2.00 -0.3 3.00 -0.4 10.0 -0.4 """)
[docs]class AbrahamsonEtAl2015SSlab(AbrahamsonEtAl2015SInter): """ Implements the Subduction GMPE developed by Norman Abrahamson, Nicholas Gregor and Kofi Addo, otherwise known as the "BC Hydro" Model, published as "BC Hydro Ground Motion Prediction Equations For Subduction Earthquakes (2013, Earthquake Spectra, in press). This implements only the inslab GMPE. For inslab events the source is considered to be a point source located at the hypocentre. Therefore the hypocentral distance metric is used in place of the rupture distance, and the hypocentral depth is used to scale the ground motion by depth """ #: Supported tectonic region type is subduction in-slab DEFINED_FOR_TECTONIC_REGION_TYPE = trt = const.TRT.SUBDUCTION_INTRASLAB #: Required distance measure is hypocentral for in-slab events REQUIRES_DISTANCES = {'rhypo'} #: In-slab events require constraint of hypocentral depth and magnitude REQUIRES_RUPTURE_PARAMETERS = {'mag', 'hypo_depth'} delta_c1 = -0.3
[docs]class AbrahamsonEtAl2015SSlabHigh(AbrahamsonEtAl2015SSlab): """ Defines the Abrahamson et al. (2013) scaling relation assuming the upper values of the magnitude scaling for large slab earthquakes, as defined in table 8 """ delta_c1 = -0.1
[docs]class AbrahamsonEtAl2015SSlabLow(AbrahamsonEtAl2015SSlab): """ Defines the Abrahamson et al. (2013) scaling relation assuming the lower values of the magnitude scaling for large slab earthquakes, as defined in table 8 """ delta_c1 = -0.5
[docs]class AbrahamsonEtAl2015SInter_scaled(AbrahamsonEtAl2015SInter): """ Implements the Subduction GMPE developed by Norman Abrahamson, Nicholas Gregor and Kofi Addo, otherwise known as the "BC Hydro" Model, published as "BC Hydro Ground Motion Prediction Equations For Subduction Earthquakes (2015, Earthquake Spectra, in press), for subduction interface events. Application of a scaling factor that converts the prediction of AbrahamsonEtAl2015SInter to the corresponding prediction for the Maximum value. """ # Period-dependent coefficients COEFFS = CoeffsTable(sa_damping=5, table="""\ IMT vlin b theta1 theta2 theta6 theta7 theta8 theta10 theta11 theta12 theta13 theta14 theta15 theta16 phi tau sigma sigma_ss pga 865.1 -1.186 4.313152617 -1.35 -0.0012 1.0988 -1.42 3.12 0.013 0.98 -0.0135 -0.4 0.9969 -1 0.6 0.43 0.74 0.6 0.05 1053.5 -1.346 4.626666443 -1.4 -0.0012 1.2536 -1.65 3.37 0.013 1.288 -0.0138 -0.4 1.103 -1.18 0.6 0.43 0.74 0.6 0.1 1032.5 -1.624 5.38940726 -1.45 -0.0012 1.3997 -1.8 3.33 0.013 1.613 -0.0145 -0.4 1.3042 -1.36 0.6 0.43 0.74 0.6 0.15 877.6 -1.931 5.561740512 -1.45 -0.0014 1.3582 -1.69 3.25 0.013 1.882 -0.0153 -0.4 1.26 -1.3 0.6 0.43 0.74 0.6 0.2 748.2 -2.188 5.381371479 -1.4 -0.0018 1.1648 -1.49 3.03 0.0129 2.076 -0.0162 -0.35 1.223 -1.25 0.6 0.43 0.74 0.6 0.3 587.1 -2.518 4.914236682 -1.28 -0.0027 0.8821 -1.18 2.59 0.0128 2.348 -0.0183 -0.28 1.05 -1.06 0.6 0.43 0.74 0.6 0.4 503 -2.657 4.591825288 -1.18 -0.0035 0.7046 -0.98 2.2 0.0127 2.427 -0.0206 -0.23 0.8 -0.78 0.6 0.43 0.74 0.6 0.5 456.6 -2.669 4.142704163 -1.08 -0.0044 0.5799 -0.82 1.92 0.0125 2.399 -0.0231 -0.19 0.662 -0.62 0.6 0.43 0.74 0.6 0.75 410.5 -2.401 3.347462884 -0.91 -0.0058 0.3687 -0.54 1.42 0.012 1.993 -0.0296 -0.12 0.48 -0.34 0.6 0.43 0.74 0.6 1 400 -1.955 2.922350962 -0.85 -0.0062 0.1746 -0.34 1.1 0.0114 1.47 -0.0363 -0.07 0.33 -0.14 0.6 0.43 0.74 0.6 2 400 -0.299 1.539520753 -0.71 -0.0064 -0.2821 0.12 0.7 0.0085 -0.401 -0.061 0 0.3 0 0.6 0.43 0.74 0.6 3 400 0 0.776117425 -0.64 -0.0064 -0.4466 0.3 0.7 0.0054 -0.673 -0.0798 0 0.3 0 0.6 0.43 0.74 0.6 4 400 0 0.202413823 -0.58 -0.0064 -0.4344 0.3 0.7 0.0027 -0.627 -0.0935 0 0.3 0 0.6 0.43 0.74 0.6 """)
[docs]class AbrahamsonEtAl2015SSlab_scaled(AbrahamsonEtAl2015SInter_scaled): """ Implements the Subduction GMPE developed by Norman Abrahamson, Nicholas Gregor and Kofi Addo, otherwise known as the "BC Hydro" Model, published as "BC Hydro Ground Motion Prediction Equations For Subduction Earthquakes (2013, Earthquake Spectra, in press). This implements only the inslab GMPE. For inslab events the source is considered to be a point source located at the hypocentre. Therefore the hypocentral distance metric is used in place of the rupture distance, and the hypocentral depth is used to scale the ground motion by depth Application of a scaling factor that converts the prediction of AbrahamsonEtAl2015SSlab to the corresponding prediction for the Maximum value. """ #: Supported tectonic region type is subduction in-slab DEFINED_FOR_TECTONIC_REGION_TYPE = trt = const.TRT.SUBDUCTION_INTRASLAB #: Required distance measure is hypocentral for in-slab events REQUIRES_DISTANCES = {'rhypo'} #: In-slab events require constraint of hypocentral depth and magnitude REQUIRES_RUPTURE_PARAMETERS = {'mag', 'hypo_depth'} delta_c1 = -0.3