# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Copyright (C) 2014-2018 GEM Foundation, Chung-Han Chan
#
# OpenQuake is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# OpenQuake is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with OpenQuake. If not, see <http://www.gnu.org/licenses/>.
"""
Module exports :class:`megawatipan2010`.
"""
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
[docs]class MegawatiPan2010(GMPE):
"""
Implements GMPE developed by Kusnowidjaja Megawati and Tso-Chien Pan
and published as "Ground-motion attenuation relationship for the
Sumatran megathrust earthquakes" (2010, Earthquake Engineering &
Structural Dynamics Volume 39, Issue 8, pages 827-845).
"""
#: Supported tectonic region type is subduction interface along the
#: Sumatra subduction zone.
DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.SUBDUCTION_INTERFACE
#: Supported intensity measure types are spectral acceleration,
#: peak ground velocity and peak ground acceleration, see table IV
#: pag. 837
DEFINED_FOR_INTENSITY_MEASURE_TYPES = set([
PGA,
PGV,
SA
])
#: Supported intensity measure component is geometric mean
#: of two horizontal components,
#####: PLEASE CONFIRM!!!!! 140709
DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.AVERAGE_HORIZONTAL
#: Supported standard deviation types is total, see equation IV page 837.
DEFINED_FOR_STANDARD_DEVIATION_TYPES = set([
const.StdDev.TOTAL
])
#: Required site parameter is only Vs30 (used to distinguish rock
#: and deep soil).
#: This GMPE is for very hard rock site condition,
#: see the abstract page 827.
REQUIRES_SITES_PARAMETERS = set(())
#: Required rupture parameters are magnitude, and focal depth, see
#: equation 10 page 226.
REQUIRES_RUPTURE_PARAMETERS = set(('mag',))
#: Required distance measure is hypocentral distance,
#: see equation 1 page 834.
REQUIRES_DISTANCES = set(('rhypo',))
[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._get_magnitude_scaling(C, rup.mag) +
self._get_distance_scaling(C, rup.mag, dists.rhypo))
if isinstance(imt, (PGA, SA)):
mean = np.log(np.exp(mean) / (100.0 * g))
stddevs = self._compute_std(C, stddev_types, len(dists.rhypo))
return mean, stddevs
def _get_magnitude_scaling(self, C, mag):
"""
Returns the magnitude scaling term
"""
return C["a0"] + C["a1"] * (mag - 6.0) + C["a2"] * (mag - 6.0) ** 2.
def _get_distance_scaling(self, C, mag, rhypo):
"""
Returns the distance scalig term
"""
return (C["a3"] * np.log(rhypo)) + (C["a4"] + C["a5"] * mag) * rhypo
def _compute_std(self, C, stddev_types, num_sites):
"""
Compute total standard deviation, see tables 3 and 4, pages 227 and
228.
"""
std_total = C['sigma']
stddevs = []
for _ in stddev_types:
stddevs.append(np.zeros(num_sites) + std_total)
return stddevs
#: Coefficient table for rock sites, see table 3 page 227.
COEFFS = CoeffsTable(sa_damping=5, table="""\
IMT a0 a1 a2 a3 a4 a5 sigma
PGV 2.369 2.0852 -0.23564 -0.87906 -0.001363 0.0001189 0.3478
PGA 3.882 1.8988 -0.11736 -1.00000 -0.001741 0.0000776 0.2379
0.50 4.068 1.9257 -0.12435 -0.99864 -0.001790 0.0000564 0.2410
0.60 4.439 1.9094 -0.13693 -0.99474 -0.002462 0.0001051 0.2496
0.70 4.836 1.8308 -0.13510 -0.99950 -0.003323 0.0001945 0.2565
0.80 4.978 1.8570 -0.12887 -1.00000 -0.003054 0.0001475 0.2626
0.90 5.108 1.9314 -0.13954 -0.98621 -0.002986 0.0001075 0.2424
1.00 4.973 1.9547 -0.13913 -0.97603 -0.002851 0.0001106 0.2343
1.20 2.729 2.0316 -0.13658 -0.60751 -0.002570 0.0000409 0.2436
1.50 2.421 1.8960 -0.07075 -0.59262 -0.002453 0.0000668 0.2614
2.00 2.670 1.8182 -0.07657 -0.62089 -0.002190 0.0000674 0.2780
3.00 1.716 1.7922 -0.01895 -0.61167 -0.001177 0.0000121 0.2944
5.00 -0.060 1.8694 -0.09103 -0.32688 -0.001765 0.0000529 0.3963
7.00 0.518 2.1948 -0.24519 -0.47529 -0.001064 0.0000189 0.4206
10.00 0.044 2.3081 -0.29060 -0.50356 -0.000848 0.0000125 0.5183
15.00 -0.525 2.5297 -0.41930 -0.52777 -0.001454 0.0001435 0.4495
20.00 -1.695 2.5197 -0.42807 -0.42096 -0.001575 0.0001498 0.4543
30.00 -2.805 2.6640 -0.42674 -0.43304 -0.001576 0.0001568 0.3686
50.00 -4.340 2.2968 -0.27844 -0.38291 -0.002564 0.0002540 0.3946
""")