Source code for openquake.hazardlib.gsim.chiou_youngs_2008_swiss

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"""
Module exports
:class:`ChiouYoungs2008SWISS01`,
:class:`ChiouYoungs2008SWISS06`,
:class:`ChiouYoungs2008SWISS04`.
"""
import numpy as np

from openquake.hazardlib import const
from openquake.hazardlib.gsim.chiou_youngs_2008_swiss_coeffs import (
    COEFFS_FS_ROCK_SWISS01, COEFFS_FS_ROCK_SWISS06, COEFFS_FS_ROCK_SWISS04)
from openquake.hazardlib.gsim.chiou_youngs_2008 import (
    ChiouYoungs2008, _get_ln_y_ref)
from openquake.hazardlib.gsim.utils_swiss_gmpe import _apply_adjustments


[docs]def get_nl(C, ln_y_ref, exp1, exp2):
    # b and c coeffs from eq. 10
    b = C['phi2'] * (exp1 - exp2)
    c = C['phi4']

    y_ref = np.exp(ln_y_ref)
    # eq. 20
    NL = b * y_ref / (y_ref + c)
    return NL


[docs]def get_tau(C, ctx):
    # eq. 19 to calculate inter-event standard error
    mag_test = np.clip(ctx.mag - 5., 0., 2.)
    tau = C['tau1'] + (C['tau2'] - C['tau1']) / 2 * mag_test
    return tau


[docs]class ChiouYoungs2008SWISS01(ChiouYoungs2008):

    """
    This class extends :class:ChiouYoungs2008,
    adjusted to be used for the Swiss Hazard Model [2014].
    This GMPE is valid for a fixed value of vs30=620m/s

    1) kappa value
       K-adjustments corresponding to model 01 - as prepared by Ben Edwards
       K-value for PGA were not provided but infered from SA[0.01s]
       the model considers a fixed value of vs30==620 to match the
       reference vs30=1100m/s

    2) small-magnitude correction

    3) single station sigma - inter-event magnitude/distance adjustment

    Disclaimer: these equations are modified to be used for the
    Swiss Seismic Hazard Model [2014].
    The use of these models in other models
    is the soly responsability of the hazard modeler.

    Model implemented by laurentiu.danciu@gmail.com
    """
    #: Supported standard deviation type is total, inter-event and intra-event
    DEFINED_FOR_STANDARD_DEVIATION_TYPES = {
        const.StdDev.TOTAL, const.StdDev.INTER_EVENT, const.StdDev.INTRA_EVENT}

    #: Vs30 value representing typical rock conditions in Switzerland.
    #: confirmed by the Swiss GMPE group
    DEFINED_FOR_REFERENCE_VELOCITY = 1105.

[docs]    def compute(self, ctx: np.recarray, imts, mean, sig, tau, phi):
        ctx = ctx.copy()
        ctx.vs30 = 620 * np.ones(len(ctx.vs30))
        log_phi_ss = 1
        super().compute(ctx, imts, mean, sig, tau, phi)

        for m, imt in enumerate(imts):
            t = get_tau(ChiouYoungs2008.COEFFS[imt], ctx)

            ln_y_ref = _get_ln_y_ref(ctx, ChiouYoungs2008.COEFFS[imt])

            exp1 = np.exp(ChiouYoungs2008.COEFFS[imt]['phi3'] *
                          (ctx.vs30.clip(-np.inf, 1130) - 360))

            exp2 = np.exp(ChiouYoungs2008.COEFFS[imt]['phi3'] * (1130 - 360))

            nl = get_nl(ChiouYoungs2008.COEFFS[imt], ln_y_ref, exp1, exp2)

            _apply_adjustments(
                ChiouYoungs2008.COEFFS, self.COEFFS_FS_ROCK[imt], 1,
                mean[m], sig[m], tau[m], phi[m], ctx, ctx.rjb, imt,
                log_phi_ss, NL=nl, tau_value=t)

    COEFFS_FS_ROCK = COEFFS_FS_ROCK_SWISS01


[docs]class ChiouYoungs2008SWISS06(ChiouYoungs2008SWISS01):
    """
    This class extends :class:ChiouYoungs2008,following same strategy
    as for :class:ChiouYoungs2008SWISS01 to be used for the
    Swiss Hazard Model [2014].
    """
    COEFFS_FS_ROCK = COEFFS_FS_ROCK_SWISS06


[docs]class ChiouYoungs2008SWISS04(ChiouYoungs2008SWISS01):
    """
    This class extends :class:ChiouYoungs2008,following same strategy
    as for :class:ChiouYoungs2008SWISS01 to be used for the
    Swiss Hazard Model [2014].
    """
    COEFFS_FS_ROCK = COEFFS_FS_ROCK_SWISS04