shakelib.conversions.imc.beyer_bommer_2006

Module implements BeyerBommer2006 class to convert between various horizontal intensity measure components.

class shakelib.conversions.imc.beyer_bommer_2006.BeyerBommer2006(imc_in, imc_out)[source]

Bases: ComponentConverter

Implements conversion for various “Intensity Measure Components” (IMCs) per Beyer and Bommer (2006).

IMC equivalencies:

OpenQuake

Beyer & Bommer

GEOMETRIC_MEAN

GMxy (Geometric mean)

HORIZONTAL

Random?

MEDIAN_HORIZONTAL

AMxy (Arithmetic mean)

GMRotI50

GMRotI50

RotD50

GMRotD50

RANDOM_HORIZONTAL

Random

GREATER_OF_TWO_HORIZONTAL

Env_xy

VERTICAL

—

Notes

  • GEOMETRIC_MEAN is the “reference” type.

  • The OQ IMC “HORIZONAL” indicates that the horizontal IMC category may be ambiguous. In these cases, we are assuming that it is a random horizontal component as a default.

  • Assumes ALL unknown IMC types are GEOMETRIC_MEAN

References

Beyer, K., & Bommer, J. J. (2006). Relationships between median values and between aleatory variabilities for different definitions of the horizontal component of motion. Bulletin of the Seismological Society of America, 96(4A), 1512-1522. [link]

convertAmpsOnce(imt, amps, rrups=None, mag=None)[source]

Returns amps converted from one IMC to another.

Important:

  • Assumes the input amps are in natural log (not linear) space

  • IMC type ‘VERTICAL’ is not supported

Parameters:

  • imt (IMT) – OpenQuake IMT of the input amps (must be one of PGA, PGV, or SA). [link] <http://docs.openquake.org/oq-hazardlib/master/imt.html>

  • amps (array) – Numpy array of ground motion amplitudes.

  • rrups (array) – A numpy array of the same shape as amps, containing the rupture distances of the ground motions. Ignored by this method.

  • mag (float) – The earthquake magnitude. Default is None. Ignored by this method.

Returns:

Numpy array of amps converted from imc_in to imc_out.

Return type:

array

convertSigmasOnce(imt, sigmas)[source]

Returns standard deviations converted from one IMC to another.

Important:

  • Assumes the input sigmas are in natural log space

  • IMC types ‘VERTICAL’ and ‘HORIZONTAL’ are not supported

Parameters:

  • imt (IMT) – OpenQuake IMT of the input sigmas (must be one of PGA, PGV, or SA) [link]

  • sigmas (array) – Numpy array of standard deviations.

Returns:

Numpy array of standard deviations converted from imc_in to

imc_out.

Return type:

array