Source code for openquake.hazardlib.scalerel.leonard2014

# -*- coding: utf-8 -*-
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#
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"""
Module :mod:`openquake.hazardlib.scalerel.leonard2014` implements
:class:`Leonard2014_SCR`
:class:`Leonard2014_Interplate`
"""
from numpy import power, log10
from openquake.hazardlib.scalerel.base import BaseMSRSigma, BaseASRSigma


class Leonard2014_SCR(BaseMSRSigma, BaseASRSigma):
    """
    Leonard, M., 2014. Self-consistent earthquake fault-scaling relations:
    Update and extension to stable continental strike-slip faults.
    Bulletin of the Seismological Society of America, 104(6), pp 2953-2965.

    Implements both magnitude-area and area-magnitude scaling relationships.
    """
    def get_median_area(self, mag, rake):
        """
        Calculates median fault area from magnitude.
        """
        if rake is None:
            # Return average of strike-slip and dip-slip curves
            return power(10.0, (mag - 4.185))
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            # strike-slip
            return power(10.0, (mag - 4.18))
        else:
            # Dip-slip (thrust or normal), and undefined rake
            return power(10.0, (mag - 4.19))

    def get_std_dev_area(self, mag, rake):
        """
        Returns zero for now
        """
        return 0.0

    def get_median_mag(self, area, rake):
        """
        Returns magnitude for a given fault area
        """
        if rake is None:
            # Return average of strike-slip and dip-slip curves
            return log10(area) + 4.185
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            # strike slip
            return log10(area) + 4.18
        else:
            # Dip slip (thrust or normal), and undefined rake
            return log10(area) + 4.19

    def get_median_width(self, mag, rake=None):
        """
        Return median rupture width (km) from magnitude for stable
        continental regions, ``log10(W) = (mag - a) / 2.5`` with
        ``a = 4.22`` for strike-slip and ``a = 4.14`` for dip-slip faults.

        Added for PR-2 of the oq-engine integration plan; the width rows
        ``MSR = 1`` of Mammarella et al. (2024) Table 1.
        """
        if rake is None:
            a = 0.5 * (4.22 + 4.14)
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            a = 4.22
        else:
            a = 4.14
        return 10.0 ** ((mag - a) / 2.5)

    def get_std_dev_width(self, mag, rake=None):
        """Return the log10 standard deviation of rupture width."""
        return 0.15

    def get_std_dev_mag(self, area, rake):
        """
        Returns zero for now
        """
        return 0.0


class Leonard2014_Interplate(BaseMSRSigma, BaseASRSigma):
    """
    Leonard, M., 2014. Self-consistent earthquake fault-scaling relations:
    Update and extension to stable continental strike-slip faults.
    Bulletin of the Seismological Society of America, 104(6), pp 2953-2965.

    Implements both magnitude-area and area-magnitude scaling relationships.
    """
    def get_median_area(self, mag, rake):
        """
        Calculates median fault area from magnitude.
        """
        if rake is None:
            # Return average of strike-slip and dip-slip curves
            return power(10.0, (mag - 3.995))
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            # strike slip
            return power(10.0, (mag - 3.99))
        else:
            # Dip slip (thrust or normal), and undefined rake
            return power(10.0, (mag - 4.00))

    def get_std_dev_area(self, mag, rake):
        """
        Returns zero for now
        """
        return 0.0

    def get_median_mag(self, area, rake):
        """
        Calculates median magnitude from fault area.
        """
        if rake is None:
            # Return average of strike-slip and dip-slip curves
            return log10(area) + 3.995
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            # strike slip
            return log10(area) + 3.99
        else:
            # Dip slip (thrust or normal), and undefined rake
            return log10(area) + 4.00

    def get_median_width(self, mag, rake=None):
        """
        Return median rupture width (km) from magnitude for interplate
        faults, ``log10(W) = (mag - a) / 2.5`` with ``a = 3.88`` for
        strike-slip and ``a = 3.63`` for dip-slip faults.

        Added for PR-2 of the oq-engine integration plan; the width rows
        ``MSR = 0`` of Mammarella et al. (2024) Table 1.
        """
        if rake is None:
            a = 0.5 * (3.88 + 3.63)
        elif (-45 <= rake <= 45) or (rake >= 135) or (rake <= -135):
            a = 3.88
        else:
            a = 3.63
        return 10.0 ** ((mag - a) / 2.5)

    def get_std_dev_width(self, mag, rake=None):
        """Return the log10 standard deviation of rupture width."""
        return 0.15

    def get_std_dev_mag(self, area, rake):
        """
        Returns None for now
        """
        return 0.0