Source code for openquake.hazardlib.gsim.atkinson_2015

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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"""
Module exports :class:'Atkinson2015'
"""
import numpy as np
from scipy.constants import g


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


def _get_magnitude_term(C, mag):
    """
    Returns the magnitude scaling term
    """
    return C["c0"] + (C["c1"] * mag) + (C["c2"] * (mag ** 2.0))


def _get_distance_term(C, rhypo, mag):
    """
    Returns the distance scaling term including the apparent anelastic
    attenuation term (C4 * R)
    """
    h_eff = _get_effective_distance(mag)
    r_val = np.sqrt(rhypo ** 2.0 + h_eff ** 2.0)
    return C["c3"] * np.log10(r_val) + C["c4"] * r_val


def _get_effective_distance(mag):
    """
    Returns the effective distance term in equation 3. This may be
    overwritten in sub-classes
    """
    h_eff = 10.0 ** (-1.72 + 0.43 * mag)
    if h_eff > 1.0:
        return h_eff
    else:
        return 1.0


def _get_stddevs(C):
    """
    Return standard deviations, converting from log10 to log
    """
    return [np.log(10.0 ** C["sigma"]),
            np.log(10.0 ** C["tau"]),
            np.log(10.0 ** C["phi"])]


[docs]class Atkinson2015(GMPE): """ Implements the Induced Seismicity GMPE of Atkinson (2015) Atkinson, G. A. (2015) Ground-Motion Prediction Equation for Small-to- Moderate Events at Short Hypocentral Distances, with Application to Induced-Seismicity Hazards. Bulletin of the Seismological Society of America. 105(2). """ #: The GMPE is derived from induced earthquakes DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.INDUCED #: Supported intensity measure types are peak ground acceleration DEFINED_FOR_INTENSITY_MEASURE_TYPES = {PGA, PGV, SA} #: Supported intensity measure component is the larger of two components DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.RotD50 #: Supported standard deviation types is total. DEFINED_FOR_STANDARD_DEVIATION_TYPES = { const.StdDev.TOTAL, const.StdDev.INTER_EVENT, const.StdDev.INTRA_EVENT} #: No required site parameters, the GMPE is derived for B/C site #: amplification factors REQUIRES_SITES_PARAMETERS = set() #: Required rupture parameters are magnitude REQUIRES_RUPTURE_PARAMETERS = {'mag', } #: Required distance measure is hypocentral distance REQUIRES_DISTANCES = {'rhypo'}
[docs] def compute(self, ctx, 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] imean = (_get_magnitude_term(C, ctx.mag) + _get_distance_term(C, ctx.rhypo, ctx.mag)) # Convert mean from cm/s and cm/s/s if imt.string.startswith(('PGA', 'SA')): mean[m] = np.log((10.0 ** (imean - 2.0)) / g) else: mean[m] = np.log(10.0 ** imean) sig[m], tau[m], phi[m] = _get_stddevs(C)
COEFFS = CoeffsTable(sa_damping=5, table=""" IMT c0 c1 c2 c3 c4 phi tau sigma pgv -4.151 1.762 -0.09509 -1.669 -0.00060 0.27 0.19 0.33 pga -2.376 1.818 -0.1153 -1.752 -0.00200 0.28 0.24 0.37 0.0300 -2.283 1.842 -0.1189 -1.785 -0.00200 0.28 0.27 0.39 0.0500 -2.018 1.826 -0.1192 -1.831 -0.00200 0.28 0.30 0.41 0.1000 -1.954 1.830 -0.1185 -1.774 -0.00200 0.29 0.25 0.39 0.2000 -2.266 1.785 -0.1061 -1.657 -0.00140 0.30 0.21 0.37 0.3000 -2.794 1.852 -0.1078 -1.608 -0.00100 0.30 0.19 0.36 0.5000 -3.873 2.060 -0.1212 -1.544 -0.00060 0.29 0.20 0.35 1.0000 -4.081 1.742 -0.07381 -1.481 0.00000 0.26 0.22 0.34 2.0000 -4.462 1.485 -0.03815 -1.361 0.00000 0.24 0.23 0.33 3.0000 -3.827 1.060 0.009086 -1.398 0.00000 0.24 0.22 0.32 5.0000 -4.321 1.080 0.009376 -1.378 0.00000 0.25 0.18 0.31 """)