Source code for openquake.hazardlib.gsim.convertito_2012

# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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Module exports :class:'ConvertitoEtAl2012Geysers'
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

def _compute_magnitude_scaling(C, mag):
    Returns the magnitude scaling term
    return C["a"] + (C["b"] * mag)

def _compute_distance_scaling(C, rhypo):
    Returns the distance scaling term accounting for geometric and
    anelastic attenuation
    return C["c"] * np.log10(np.sqrt((rhypo ** 2.) + (C["h"] ** 2.))) +\
        (C["d"] * rhypo)

def _compute_site_scaling(C, vs30):
    Returns the site scaling term as a simple coefficient
    site_term = np.zeros(len(vs30), dtype=float)
    # For soil sites add on the site coefficient
    site_term[vs30 < 760.0] = C["e"]
    return site_term

[docs]class ConvertitoEtAl2012Geysers(GMPE): """ Implements the PGA GMPE for Induced Seismicity in the Geysers Geothermal field, published in Convertito, V., Maercklin, N., Sharma, N., and Zollo, A. (2012) From Induced Seismicity to Direct Time-Dependent Seismic Hazard. Bulletin of the Seismological Society of America, 102(6), 2563 - 2573 """ #: The GMPE is derived from induced earthquakes in the Geysers Geothermal #: field DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.GEOTHERMAL #: Supported intensity measure types are peak ground acceleration DEFINED_FOR_INTENSITY_MEASURE_TYPES = {PGA} #: Supported intensity measure component is the larger of two components DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = ( const.IMC.GREATER_OF_TWO_HORIZONTAL) #: Supported standard deviation types is total. DEFINED_FOR_STANDARD_DEVIATION_TYPES = {const.StdDev.TOTAL} #: Required site parameters. The GMPE was developed for two site conditions #: "with" and "without" site effect. No information is given regarding #: the soil conditions, so we assume "with site effect" to correspond #: to NEHRP Classes C, D or E (i.e. Vs30 < 760), and "without site effect" #: to corresponse to NEHRP Classes A and B (i.e. Vs30 >= 760) REQUIRES_SITES_PARAMETERS = {'vs30'} #: Required rupture parameters are magnitude REQUIRES_RUPTURE_PARAMETERS = {'mag'} #: Required distance measure is hypocentral distance REQUIRES_DISTANCES = {'rhypo'} #: GMPE not tested against independent implementation so raise #: not verified warning non_verified = True
[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] mean[m] = (_compute_magnitude_scaling(C, ctx.mag) + _compute_distance_scaling(C, ctx.rhypo) + _compute_site_scaling(C, ctx.vs30)) # Original GMPE returns log acceleration in m/s/s # Converts to natural logarithm of g mean[m] = np.log((10.0 ** mean[m]) / g) sig[m] = np.log(10.0 ** C["sigma"])
COEFFS = CoeffsTable(sa_damping=5, table=""" IMT a b c d h e sigma pga -2.268 1.276 -3.528 0.053 3.5 0.218 0.324 """)