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
# standard acceleration of gravity in m/s**2
from scipy.constants import g

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

[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 = set([ 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 = set([ 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 = set(('vs30',)) #: Required rupture parameters are magnitude REQUIRES_RUPTURE_PARAMETERS = set(('mag', )) #: Required distance measure is hypocentral distance REQUIRES_DISTANCES = set(('rhypo',)) #: GMPE not tested against independent implementation so raise #: not verified warning non_verified = True
[docs] def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types): """ See :meth:`superclass method <.base.GroundShakingIntensityModel.get_mean_and_stddevs>` for spec of input and result values. """ assert all(stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES for stddev_type in stddev_types) C = self.COEFFS[imt] mean = (self._compute_magnitude_scaling(C, rup.mag) + self._compute_distance_scaling(C, dists.rhypo) + self._compute_site_scaling(C, sites.vs30)) # Original GMPE returns log acceleration in m/s/s # Converts to natural logarithm of g mean = np.log((10.0 ** mean) / g) stddevs = self._compute_stddevs(C, dists.rhypo.shape, stddev_types) return mean, stddevs
def _compute_magnitude_scaling(self, C, mag): """ Returns the magnitude scaling term """ return C["a"] + (C["b"] * mag) def _compute_distance_scaling(self, 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(self, 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 def _compute_stddevs(self, C, num_sites, stddev_types): """ Return total standard deviation. """ stddevs = [] for _ in stddev_types: stddevs.append(np.zeros(num_sites) + np.log(10.0 ** C["sigma"])) return stddevs 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 """)