Source code for openquake.hazardlib.imt

# -*- coding: utf-8 -*-
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"""
Module :mod:`openquake.hazardlib.imt` defines different intensity measure
types.
"""
import re
import collections
import numpy

FREQUENCY_PATTERN = '^(EAS|FAS|DRVT)\\((\\d+\\.*\\d*)\\)'


[docs]def positivefloat(val): """ Raise a ValueError if val <= 0 """ if val <= 0: raise ValueError(val)
[docs]def imt2tup(string): """ >>> imt2tup('PGA') ('PGA',) >>> imt2tup('SA(1.0)') ('SA(1.0)', 1.0) >>> imt2tup('SA(1)') ('SA(1.0)', 1.0) """ s = string.strip() name, *rest = s.split('(') if name not in globals(): raise KeyError(name) elif len(name) > 12: raise NameError('IMT class name longer than 12 chars: %s' % name) elif not rest: if name == 'SA': raise ValueError('Missing period in SA') # no parenthesis, PGA is considered the same as PGA() return (s,) period = float(rest[0][:-1]) return ('SA(%s)' % period, period)
[docs]def from_string(imt, _damping=5.0): """ Convert an IMT string into an hazardlib object. :param str imt: Intensity Measure Type. """ m = re.match(FREQUENCY_PATTERN, imt) if m: if m.group(1) == 'EAS': im = EAS(float(m.group(2))) elif m.group(1) == 'FAS': im = FAS(float(m.group(2))) elif m.group(1) == 'DRVT': im = DRVT(float(m.group(2))) return im elif re.match(r'[ \+\d\.]+', imt): return SA(float(imt)) return IMT(*imt2tup(imt))
[docs]def repr(self): if self.period and self.damping != 5.0: return 'SA(%s, %s)' % (self.period, self.damping) return self.string
IMT = collections.namedtuple('IMT', 'string period damping') IMT.__new__.__defaults__ = (0., 5.0) IMT.__lt__ = lambda self, other: self[1] < other[1] IMT.__gt__ = lambda self, other: self[1] > other[1] IMT.__le__ = lambda self, other: self[1] <= other[1] IMT.__ge__ = lambda self, other: self[1] >= other[1] IMT.__repr__ = repr IMT.frequency = property(lambda self: 1. / self.period)
[docs]def PGA(): """ Peak ground acceleration during an earthquake measured in units of ``g``, times of gravitational acceleration. """ return IMT('PGA')
[docs]def PGV(): """ Peak ground velocity during an earthquake measured in units of ``cm/sec``. """ return IMT('PGV')
[docs]def PGD(): """ Peak ground displacement during an earthquake measured in units of ``cm``. """ return IMT('PGD')
[docs]def EAS(frequency): """ Effective Amplitude Spectrum in terms of a frequency (in Hz). """ period = 1. / frequency return IMT('EAS(%s)' % period, period, 5.0)
[docs]def FAS(frequency): """ Fourier Amplitude Spectrum in terms of a frequency (in Hz). """ period = 1. / frequency return IMT('FAS(%s)' % period, period, 5.0)
[docs]def DRVT(frequency): """ Duration as defined in Bora et al. (2019) """ period = 1. / frequency return IMT('DRVT(%s)' % period, period, 5.0)
[docs]def SA(period, damping=5.0): """ Spectral acceleration, defined as the maximum acceleration of a damped, single-degree-of-freedom harmonic oscillator. Units are ``g``, times of gravitational acceleration. """ period = float(period) return IMT('SA(%s)' % period, period, damping)
[docs]def AvgSA(): """ Dummy spectral acceleration to compute average ground motion over several spectral ordinates. """ return IMT('AvgSA')
[docs]def IA(): """ Arias intensity. Determines the intensity of shaking by measuring the acceleration of transient seismic waves. Units are ``m/s``. """ return IMT('IA')
[docs]def CAV(): """ Cumulative Absolute Velocity. Defins the integral of the absolute acceleration time series. Units are "g-sec" """ return IMT('CAV')
[docs]def RSD(): """ Relative significant duration, 5-95% of :class:`Arias intensity<IA>`, in seconds. """ return IMT('RSD')
[docs]def RSD595(): """ Alias for RSD """ return IMT('RSD595')
[docs]def RSD575(): """ Relative significant duration, 5-75% of :class:`Arias intensity<IA>`, in seconds. """ return IMT('RSD575')
[docs]def RSD2080(): """ Relative significant duration, 20-80% of :class:`Arias intensity<IA>`, in seconds. """ return IMT('RSD2080')
[docs]def MMI(): """ Modified Mercalli intensity, a Roman numeral describing the severity of an earthquake in terms of its effects on the earth's surface and on humans and their structures. """ return IMT('MMI')
[docs]def JMA(): """ Modified Mercalli intensity, a Roman numeral describing the severity of an earthquake in terms of its effects on the earth's surface and on humans and their structures. """ return IMT('JMA')
# Volcanic IMTs
[docs]def ASH(): """ Level of the ash fall in millimeters """ return IMT('ASH')
# secondary perils
[docs]def Disp(): """ Displacement """ return IMT('Disp')
[docs]def DispProb(): """ Displacement probability """ return IMT('RSD595')
[docs]def LiqProb(): """ Liquefaction probability """ return IMT('LiqProb')
[docs]def PGDMax(vert_settlement, lat_spread): """ Maximum between vert_settlement and lat_spread """ return numpy.maximum(vert_settlement, lat_spread)
[docs]def PGDGeomMean(vert_settlement, lat_spread): """ Geometric mean between vert_settlement and lat_spread """ return numpy.sqrt(vert_settlement * lat_spread)