Source code for openquake.hazardlib.scalerel.wc1994

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"""
Module :mod:`openquake.hazardlib.scalerel.wc1994` implements :class:`WC1994`.
"""
from math import log10
from openquake.hazardlib.scalerel.base import BaseMSRSigma, BaseASRSigma


[docs]class WC1994(BaseMSRSigma, BaseASRSigma): """ Wells and Coppersmith magnitude -- rupture area relationships, see 1994, Bull. Seism. Soc. Am., pages 974-2002. Implements both magnitude-area and area-magnitude scaling relationships. """
[docs] def get_median_area(self, mag, rake): """ The values are a function of both magnitude and rake. Setting the rake to ``None`` causes their "All" rupture-types to be applied. """ if rake is None: # their "All" case return 10.0 ** (-3.49 + 0.91 * mag) elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135): # strike slip return 10.0 ** (-3.42 + 0.90 * mag) elif rake > 0: # thrust/reverse return 10.0 ** (-3.99 + 0.98 * mag) else: # normal return 10.0 ** (-2.87 + 0.82 * mag)
[docs] def get_std_dev_area(self, mag, rake): """ Standard deviation for WC1994. Magnitude is ignored. """ if rake is None: # their "All" case return 0.24 elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135): # strike slip return 0.22 elif rake > 0: # thrust/reverse return 0.26 else: # normal return 0.22
[docs] def get_std_dev_mag(self, area, rake): """ Standard deviation on the magnitude for the WC1994 area relation. """ if rake is None: # their "All" case return 0.24 elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135): # strike slip return 0.23 elif rake > 0: # thrust/reverse return 0.25 else: # normal return 0.25
[docs] def get_median_mag(self, area, rake): """ Return magnitude (Mw) given the area and rake. Setting the rake to ``None`` causes their "All" rupture-types to be applied. :param area: Area in square km. :param rake: Rake angle (the rupture propagation direction) in degrees, from -180 to 180. """ if rake is None: # their "All" case return 4.07 + 0.98 * log10(area) elif (-45 <= rake <= 45) or (rake > 135) or (rake < -135): # strike slip return 3.98 + 1.02 * log10(area) elif rake > 0: # thrust/reverse return 4.33 + 0.90 * log10(area) else: # normal return 3.93 + 1.02 * log10(area)