shakelib.gmice.wald99

class shakelib.gmice.wald99.Wald99[source]

Bases: GMICE

Implements the ground motion intensity conversion equations (GMICE) of Wald et al. (1999). This module implements a simplified version in that it only uses one of PGV or PGA, and not a combination of the two (PGV for higher intensities, PGA for lower) as is recommended in the reference.

References

Wald, D.J., V. Quitoriano, T.H. Heaton, and H. Kanamori (1999). Relationships between peak gorund acceleration, peak ground velocity, and Modified Mercalli Intensity in California, Earthquake Spectra, Volume15, No. 3, August 1999.

getPreferredMI(df, dists=None, mag=None)[source]

Function to compute macroseismic intensity from the preferred ground-motion intensity. The function uses PGV by default, but this may be overridden by individual classes.

Parameters:

  • df (dict) – Dictionaary containing all of the available ground motions.

  • dists (ndarray) – Numpy array of distances from rupture (km).

  • mag (float) – Earthquake magnitude.

Returns:

ndarray of Modified Mercalli Intensity and ndarray of dMMI / dln(amp) (i.e., the slope of the relationship at the point in question).

getMIfromGM(amps, imt, dists=None, mag=None)[source]

Function to compute macroseismic intensity from ground-motion intensity. Supported ground-motion IMTs are PGA and PGV

Parameters:

  • amps (ndarray) – Ground motion amplitude; natural log units; g for PGA and PSA, cm/s for PGV.

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

  • dists (ndarray) – Numpy array of distances from rupture (km). This parameter is ignored by this GMICE.

  • mag (float) – Earthquake magnitude. This parameter is ignored by this GMICE.

Returns:

ndarray of Modified Mercalli Intensity and ndarray of dMMI / dln(amp) (i.e., the slope of the relationship at the point in question).

getGMfromMI(mmi, imt, dists=None, mag=None)[source]

Function to tcompute ground-motion intensity from macroseismic intensity. Supported IMTs are PGA and PGV.

Parameters:

  • mmi (ndarray) – Macroseismic intensity.

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

  • dists (ndarray) – Rupture distances (km) to the corresponding MMIs. This parameter is ignored by this GMICE.

  • mag (float) – Earthquake magnitude. This parameter is ignored by this GMICE.

Returns:

Ndarray of ground motion intensity in natural log of g for PGA and PSA, and natural log cm/s for PGV; ndarray of dln(amp) / dMMI (i.e., the slope of the relationship at the point in question).

getGM2MIsd()[source]

Return a dictionary of standard deviations for the ground-motion to MMI conversion. The keys are the ground motion types.

Returns:

Dictionary of GM to MI sigmas (in MMI units).

getMI2GMsd()[source]

Return a dictionary of standard deviations for the MMI to ground-motion conversion. The keys are the ground motion types.

Returns:

Dictionary of MI to GM sigmas (ln(PGM) units).