Source code for openquake.hazardlib.gsim.megawati_2003
# -*- coding: utf-8 -*-
# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Copyright (C) 2014-2025 GEM Foundation
#
# 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.
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# 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:`megawatiEtAl2003`.
"""
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_azimuth_correction(coe, azimuth):
"""
This is the azimuth correction defined in the functional form (see
equation 3 at page 2256)
"""
term1 = abs(np.cos(np.radians(2.*azimuth)))
term2 = abs(np.sin(np.radians(2.*azimuth)))*coe['a5']
return np.log(np.max(np.hstack((term1, term2))))
def _get_distance_scaling(coe, rhypo):
"""
Returns the distance scaling term
"""
return coe["a3"] * np.log(rhypo) + coe["a4"] * rhypo
def _get_magnitude_scaling(coe, mag):
"""
Returns the magnitude scaling term
"""
return coe["a0"] + coe["a1"] * mag + coe["a2"] * mag**2.
[docs]class MegawatiEtAl2003(GMPE):
"""
Implements GMPE developed by Megawati, Pan and Koketsu and published in
2003 as "Response spectral attenuation relationships for Singapore and the
Malay Peninsula due to distant Sumatran-fault earthquakes", Earthquake
Engineering & Structural Dynamics Volume 32, pages 2241–2265.
"""
#: Supported tectonic region type is active shallow crust
#: Sumatra strike-slip fault
DEFINED_FOR_TECTONIC_REGION_TYPE = const.TRT.ACTIVE_SHALLOW_CRUST
#: Supported intensity measure types are spectral acceleration,
#: peak ground veloacity and peak ground acceleration
DEFINED_FOR_INTENSITY_MEASURE_TYPES = {PGA, PGV, SA}
#: Supported intensity measure component is geometric mean
#: of two horizontal components,
DEFINED_FOR_INTENSITY_MEASURE_COMPONENT = const.IMC.GEOMETRIC_MEAN
#: Supported standard deviation types is total
DEFINED_FOR_STANDARD_DEVIATION_TYPES = {const.StdDev.TOTAL}
#: No site parameter required. This GMPE is for very hard rock conditions
REQUIRES_SITES_PARAMETERS = set()
#: Required rupture parameter is magnitude
REQUIRES_RUPTURE_PARAMETERS = {'mag'}
#: Required distance measure is hypocentral distance, and azimuth
REQUIRES_DISTANCES = {'rhypo', 'azimuth'}
[docs] def compute(self, ctx: np.recarray, 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):
coe = self.COEFFS[imt]
mean[m] = (_get_magnitude_scaling(coe, ctx.mag) +
_get_distance_scaling(coe, ctx.rhypo) +
_get_azimuth_correction(coe, ctx.azimuth))
# Convert to g
if imt.string.startswith(("PGA", "SA")):
mean[m] = np.log(np.exp(mean[m]) / (100.0 * g))
# Compute std
sig[m] = coe['sigma']
#: Coefficient table for rock ctx, see table 3 page 2257
COEFFS = CoeffsTable(sa_damping=5, table="""\
IMT a0 a1 a2 a3 a4 a5 sigma
PGV -13.512 3.8980 -0.129363 -1.0000 -0.000887 0.1286 0.3740
PGA -8.167 2.7779 -0.045945 -1.0000 -0.001906 0.1356 0.3511
0.50 -6.190 2.5075 -0.023022 -1.0000 -0.002847 0.2049 0.3432
0.55 -5.965 2.4599 -0.019483 -1.0000 -0.002834 0.1859 0.3423
0.60 -5.831 2.4234 -0.016979 -1.0000 -0.002763 0.1754 0.3358
0.65 -5.619 2.3407 -0.010115 -1.0000 -0.002683 0.1712 0.3383
0.70 -5.425 2.2721 -0.004676 -1.0000 -0.002601 0.1542 0.3509
0.75 -5.380 2.2521 -0.003320 -1.0000 -0.002510 0.1510 0.3650
0.80 -5.528 2.2516 -0.003498 -0.9790 -0.002431 0.1531 0.3726
0.85 -5.778 2.2476 -0.003025 -0.9421 -0.002398 0.1551 0.3683
0.90 -5.790 2.2218 -0.000880 -0.9360 -0.002332 0.1529 0.3735
0.95 -6.094 2.2605 -0.004202 -0.9075 -0.002299 0.1492 0.3787
1.00 -6.396 2.3033 -0.007976 -0.8811 -0.002250 0.1450 0.3775
1.10 -6.862 2.3479 -0.011760 -0.8375 -0.002148 0.1403 0.3914
1.20 -7.661 2.4732 -0.021870 -0.7801 -0.002080 0.1370 0.4034
1.30 -8.447 2.5829 -0.030536 -0.7182 -0.002022 0.1444 0.3903
1.40 -8.729 2.5796 -0.029935 -0.6847 -0.001955 0.1460 0.3857
1.50 -9.002 2.6385 -0.034455 -0.6849 -0.001866 0.1429 0.3917
1.60 -9.599 2.8548 -0.051636 -0.7163 -0.001713 0.1381 0.3935
1.70 -10.069 2.9852 -0.062163 -0.7195 -0.001603 0.1352 0.4030
1.80 -10.449 3.0345 -0.066243 -0.6909 -0.001545 0.1334 0.4138
1.90 -10.888 3.0905 -0.070529 -0.6560 -0.001512 0.1314 0.4215
2.00 -11.553 3.2211 -0.080618 -0.6191 -0.001527 0.1322 0.4261
2.20 -12.586 3.4295 -0.096925 -0.5719 -0.001506 0.1303 0.4642
2.40 -13.313 3.5537 -0.106129 -0.5401 -0.001436 0.1327 0.4928
2.60 -14.023 3.7036 -0.117145 -0.5248 -0.001363 0.1354 0.4987
2.80 -14.747 3.8781 -0.130894 -0.5145 -0.001310 0.1359 0.4916
3.00 -15.204 4.0192 -0.141834 -0.5396 -0.001176 0.1379 0.4687
3.20 -15.571 4.1214 -0.149159 -0.5631 -0.001031 0.1429 0.4571
3.40 -16.028 4.2365 -0.157839 -0.5734 -0.000912 0.1472 0.4532
3.60 -16.682 4.3508 -0.166237 -0.5417 -0.000911 0.1503 0.4473
3.80 -17.249 4.4454 -0.172847 -0.5129 -0.000930 0.1547 0.4389
4.00 -17.832 4.5516 -0.180406 -0.4906 -0.000918 0.1711 0.4268
4.20 -18.330 4.6497 -0.187109 -0.4774 -0.000907 0.1741 0.4137
4.40 -18.783 4.7669 -0.195587 -0.4804 -0.000881 0.1768 0.4016
4.60 -19.139 4.8543 -0.201619 -0.4838 -0.000857 0.1796 0.3970
4.80 -19.462 4.9128 -0.205331 -0.4756 -0.000861 0.1841 0.3911
5.00 -19.772 4.9712 -0.209015 -0.4699 -0.000862 0.1887 0.3847
5.50 -20.538 5.1717 -0.223871 -0.4814 -0.000816 0.2035 0.3740
6.00 -20.812 5.2707 -0.230283 -0.5326 -0.000680 0.2244 0.3741
6.50 -21.142 5.3397 -0.234073 -0.5513 -0.000626 0.2295 0.3720
7.00 -21.702 5.5028 -0.245792 -0.5773 -0.000569 0.2479 0.3771
7.50 -22.037 5.5940 -0.251227 -0.6049 -0.000532 0.2538 0.3910
8.00 -22.199 5.6220 -0.251133 -0.6306 -0.000507 0.2574 0.4111
8.50 -22.371 5.6944 -0.255129 -0.6780 -0.000397 0.2621 0.4196
9.00 -22.632 5.7649 -0.259591 -0.7002 -0.000319 0.2636 0.4144
9.50 -22.918 5.8431 -0.265147 -0.7169 -0.000260 0.2631 0.4087
10.00 -23.078 5.8682 -0.266233 -0.7268 -0.000222 0.2619 0.4056
11.00 -22.998 5.7565 -0.254562 -0.7317 -0.000176 0.2517 0.3968
12.00 -23.017 5.7090 -0.249180 -0.7423 -0.000138 0.2437 0.3854
13.00 -23.091 5.7515 -0.252199 -0.7820 -0.000071 0.2412 0.3778
14.00 -22.970 5.7395 -0.250671 -0.8244 -0.000011 0.2309 0.3729
15.00 -22.947 5.7004 -0.246974 -0.8330 -0.000000 0.2287 0.3707
16.00 -22.907 5.6432 -0.241860 -0.8330 -0.000000 0.2266 0.3683
17.00 -22.816 5.5623 -0.234844 -0.8276 -0.000009 0.2226 0.3657
18.00 -22.726 5.4955 -0.229113 -0.8274 -0.000015 0.2168 0.3636
19.00 -22.761 5.4510 -0.225431 -0.8087 -0.000085 0.1936 0.3632
20.00 -22.928 5.4329 -0.224139 -0.7800 -0.000167 0.1865 0.3629
""")
