Source code for openquake.hazardlib.gsim.youngs_1997

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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"""
Module exports :class:`YoungsEtAl1997SInter`, :class:`YoungsEtAl1997SSlab`,
:class:`YoungsEtAl1997GSCSSlabBest`, :class:`YoungsEtAl1997GSCSSlabUpperLimit`,
:class:`YoungsEtAl1997GSCSSlabLowerLimit`,
:class:`YoungsEtAl1997SInterNSHMP2008`.
"""
import numpy as np
import copy

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

#: constants for mean value calculation, see table 2, page 67.
CONSTS = {'A1_rock': 0.2418,
          'A2_rock': 1.414,
          'A3_rock': 10,
          'A4_rock': 1.7818,
          'A5_rock': 0.554,
          'A6_rock': 0.00607,
          'A7_rock': 0.3846,
          'A1_soil': -0.6687,
          'A2_soil': 1.438,
          'A3_soil': 10,
          'A4_soil': 1.097,
          'A5_soil': 0.617,
          'A6_soil': 0.00648,
          'A7_soil': 0.3643}


def _compute_mean(C, A1, A2, A3, A4, A5, A6, mag, hypo_depth,
                  rrup, mean, idx):
    """
    Compute mean for subduction interface events, as explained in table 2,
    page 67.
    """
    if isinstance(mag, np.ndarray):
        mag = mag[idx]
        hypo_depth = hypo_depth[idx]
    mean[idx] = (A1 + A2 * mag + C['C1'] + C['C2'] * (A3 - mag) ** 3 +
                 C['C3'] * np.log(rrup[idx] + A4 * np.exp(A5 * mag)) +
                 A6 * hypo_depth)


[docs]def get(array, idx): return array[idx] if isinstance(array, np.ndarray) else array
[docs]class YoungsEtAl1997SInter(GMPE): """ Implements GMPE developed by R.R Youngs, S-J, Chiou, W.J. Silva, J.R. Humphrey and published as "Strong Ground Motion Attenuation Relationships for Subduction Zone Earthquakes" (Seismological Research Letters Volume 68, No. 1, pages 58-73, 1997). This class implements the equations for 'Subduction Interface' (that's why the class name ends with 'SInter'). Mean value for SA at 4 s on rock (not originally supported) is obtained from mean value at 3 s divided by a factor equal to 0.399 (scaling factor computed in the context of the SHARE project obtained as average ratio between median values at 4 and 3 seconds as predicted by SHARE subduction GMPEs). """ #: Supported tectonic region type is subduction interface DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.SUBDUCTION_INTERFACE #: Supported intensity measure types are spectral acceleration, #: and peak ground acceleration, see table 2, page 67. DEFINED_FOR_INTENSITY_MEASURE_TYPES = {PGA, SA} #: Supported intensity measure component is the average horizontal #: component #: attr:`~openquake.hazardlib.const.IMC.AVERAGE_HORIZONTAL`, see #: paragraph: 'Analysis of peak horizontal accelerations', p. 59. DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.AVERAGE_HORIZONTAL #: Supported standard deviation types is total, table 2, page 67. DEFINED_FOR_STANDARD_DEVIATION_TYPES = {const.StdDev.TOTAL} DEFINED_FOR_REFERENCE_VELOCITY = 800 #: Required site parameters is Vs30, used to distinguish between rock #: and soil ctx, see paragraph 'Strong Motion Data Base', page 59. REQUIRES_SITES_PARAMETERS = {'vs30'} #: Required rupture parameters are magnitude and focal depth, see #: equations 1 and 2, pages 59 and 66, respectively. REQUIRES_RUPTURE_PARAMETERS = {'mag', 'hypo_depth'} #: Required distance measure is Rrup, see equations 1 and 2, page 59 and #: 66, respectively. REQUIRES_DISTANCES = {'rrup'} #: Vs30 value representing typical rock conditions in California. ROCK_VS30 = 760 delta = 0 # changed in subclasses
[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. """ if self.__class__.__name__.endswith('NSHMP2008'): # NSHMP2008 adjustement of the hypo_depth ctx = copy.copy(ctx) ctx.hypo_depth = 20. idx_rock = ctx.vs30 >= self.ROCK_VS30 idx_soil = ctx.vs30 < self.ROCK_VS30 for m, imt in enumerate(imts): if idx_rock.any(): C = self.COEFFS_ROCK[imt] _compute_mean(C, CONSTS['A1_rock'], CONSTS['A2_rock'], CONSTS['A3_rock'], CONSTS['A4_rock'], CONSTS['A5_rock'], CONSTS['A6_rock'], ctx.mag, ctx.hypo_depth, ctx.rrup, mean[m], idx_rock) sig[m, idx_rock] += C['C4'] + C['C5'] * np.clip( get(ctx.mag, idx_rock), 0, 8.) if imt == SA(period=4.0, damping=5.0): mean[m] /= 0.399 if idx_soil.any(): C = self.COEFFS_SOIL[imt] _compute_mean(C, CONSTS['A1_soil'], CONSTS['A2_soil'], CONSTS['A3_soil'], CONSTS['A4_soil'], CONSTS['A5_soil'], CONSTS['A6_soil'], ctx.mag, ctx.hypo_depth, ctx.rrup, mean[m], idx_soil) sig[m, idx_soil] += C['C4'] + C['C5'] * np.clip( get(ctx.mag, idx_soil), 0, 8.) if (self.DEFINED_FOR_TECTONIC_REGION_TYPE == const.TRT.SUBDUCTION_INTRASLAB): # sslab correction if imt.period == 4.0: mean[m, idx_rock] += 0.3846 / 0.399 else: mean[m, idx_rock] += 0.3846 mean[m, idx_soil] += 0.3643 mean += self.delta
#: Coefficient table containing soil coefficients, #: taken from table 2, p. 67 COEFFS_SOIL = CoeffsTable(sa_damping=5, table="""\ IMT C1 C2 C3 C4 C5 pga 0.000 0.0000 -2.329 1.45 -0.1 0.075 2.400 -0.0019 -2.697 1.45 -0.1 0.100 2.516 -0.0019 -2.697 1.45 -0.1 0.200 1.549 -0.0020 -2.464 1.45 -0.1 0.300 0.793 -0.0020 -2.327 1.45 -0.1 0.400 0.144 -0.0035 -2.230 1.45 -0.1 0.500 -0.438 -0.0048 -2.140 1.45 -0.1 0.750 -1.704 -0.0066 -1.952 1.45 -0.1 1.000 -2.870 -0.0114 -1.785 1.45 -0.1 1.500 -5.101 -0.0164 -1.470 1.50 -0.1 2.000 -6.433 -0.0221 -1.290 1.55 -0.1 3.000 -6.672 -0.0235 -1.347 1.65 -0.1 4.000 -7.618 -0.0235 -1.272 1.65 -0.1 """) #: Coefficient table containing rock coefficients, #: taken from table 2, p. 67 COEFFS_ROCK = CoeffsTable(sa_damping=5, table="""\ IMT C1 C2 C3 C4 C5 pga 0.000 0.0000 -2.552 1.45 -0.1 0.075 1.275 0.0000 -2.707 1.45 -0.1 0.100 1.188 -0.0011 -2.655 1.45 -0.1 0.200 0.722 -0.0027 -2.528 1.45 -0.1 0.300 0.246 -0.0036 -2.454 1.45 -0.1 0.400 -0.115 -0.0043 -2.401 1.45 -0.1 0.500 -0.400 -0.0048 -2.360 1.45 -0.1 0.750 -1.149 -0.0057 -2.286 1.45 -0.1 1.000 -1.736 -0.0064 -2.234 1.45 -0.1 1.500 -2.634 -0.0073 -2.160 1.50 -0.1 2.000 -3.328 -0.0080 -2.107 1.55 -0.1 3.000 -4.511 -0.0089 -2.033 1.65 -0.1 4.000 -4.511 -0.0089 -2.033 1.65 -0.1 """)
[docs]class YoungsEtAl1997SInterNSHMP2008(YoungsEtAl1997SInter): """ Extends :class:`YoungsEtAl1997SInter` and fix rupture hypocenter depth at 20 km as defined by the National Seismic Hazard Mapping Project (NSHMP) for the 2008 US model. The class implement the equation as coded in ``subroutine getGeom`` in ``hazSUBXnga.f`` Fortran code available at: http://earthquake.usgs.gov/hazards/products/conterminous/2008/software/ """
[docs]class YoungsEtAl1997SSlab(YoungsEtAl1997SInter): """ Implements GMPE developed by R.R Youngs, S-J, Chiou, W.J. Silva, J.R. Humphrey and published as "Strong Ground Motion Attenuation Relationships for Subduction Zone Earthquakes" (Seismological Research Letters Volume 68, No. 1, pages 58-73, 1997). This class implements the equations for 'Subduction IntraSlab' (that's why the class name ends with 'SSlab'). Mean value for SA at 4 s on rock (not originally supported) is obtained from mean value at 3 s divided by a factor equal to 0.399 (scaling factor computed in the context of the SHARE project obtained as average ratio between median values at 4 and 3 seconds as predicted by SHARE subduction GMPEs). """ #: Supported tectonic region type is subduction intraslab DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.SUBDUCTION_INTRASLAB
[docs]class YoungsEtAl1997GSCSSlabBest(YoungsEtAl1997SSlab): """ Implement modification to :class:`YoungsEtAl1997SSlab` as defined by GSC (Geological Survey of Canada) for the 2010 Western Canada Model. Includes adjustement for firm ground. The model is associated to the 'Best' case, that is mean value unaffected. """ delta = np.log(1.162)
[docs]class YoungsEtAl1997GSCSSlabUpperLimit(YoungsEtAl1997GSCSSlabBest): """ Implement modification to :class:`YoungsEtAl1997SSlab` as defined by GSC (Geological Survey of Canada) for the 2010 Western Canada Model. Includes adjustement for firm ground. The model is associated to the 'Upper Limit' case, that is mean value plus 0.7 natural logarithm. """ delta = np.log(1.162) + 0.7
[docs]class YoungsEtAl1997GSCSSlabLowerLimit(YoungsEtAl1997GSCSSlabBest): """ Implement modification to :class:`YoungsEtAl1997SSlab` as defined by GSC (Geological Survey of Canada) for the 2010 Western Canada Model. Includes adjustement for firm ground. The model is associated to the 'Lower Limit' case, that is mean value minus 0.7 natural logarithm. """ delta = np.log(1.162) - 0.7