Source code for openquake.hazardlib.source.base

# The Hazard Library
# Copyright (C) 2012-2018 GEM Foundation
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
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Module :mod:`openquake.hazardlib.source.base` defines a base class for
seismic sources.
import abc
import math
from openquake.baselib.slots import with_slots

[docs]@with_slots class BaseSeismicSource(metaclass=abc.ABCMeta): """ Base class representing a seismic source, that is a structure generating earthquake ruptures. :param source_id: Some (numeric or literal) source identifier. Supposed to be unique within the source model. :param name: String, a human-readable name of the source. :param tectonic_region_type: Source's tectonic regime. See :class:`openquake.hazardlib.const.TRT`. """ _slots_ = ['source_id', 'name', 'tectonic_region_type', 'src_group_id', 'num_ruptures', 'seed', 'id', 'min_mag'] RUPTURE_WEIGHT = 1. # overridden in (Multi)PointSource, AreaSource ngsims = 1 min_mag = 0 # set in get_oqparams and CompositeSourceModel.filter @abc.abstractproperty def MODIFICATIONS(self): pass @property def weight(self): """ Determine the source weight from the number of ruptures, by multiplying with the scale factor RUPTURE_WEIGHT """ if not self.num_ruptures: self.num_ruptures = self.count_ruptures() # (MS) the weight is proportional to the number of ruptures and GSIMs # the relation to the number of sites is unclear, but for sure less # than linear and I am using a sqrt here (totally made up but good) return (self.num_ruptures * self.RUPTURE_WEIGHT * math.sqrt(self.nsites) * self.ngsims) @property def nsites(self): """ :returns: the number of sites affected by this source """ try: # the engine sets self.indices when filtering the sources return len(self.indices) except AttributeError: # this happens in several hazardlib tests, therefore we return # a fake number of affected sites to avoid changing all tests return 1 @property def src_group_ids(self): """ :returns: a list of source group IDs (usually of 1 element) """ grp_id = getattr(self, 'src_group_id', [0]) return [grp_id] if isinstance(grp_id, int) else grp_id def __init__(self, source_id, name, tectonic_region_type): self.source_id = source_id = name self.tectonic_region_type = tectonic_region_type self.src_group_id = 0 # set by the engine self.num_ruptures = 0 # set by the engine self.seed = None # set by the engine = None # set by the engine
[docs] @abc.abstractmethod def iter_ruptures(self): """ Get a generator object that yields probabilistic ruptures the source consists of. :returns: Generator of instances of sublclass of :class: `~openquake.hazardlib.source.rupture.BaseProbabilisticRupture`. """
def __iter__(self): """ Override to implement source splitting """ yield self
[docs] @abc.abstractmethod def count_ruptures(self): """ Return the number of ruptures that will be generated by the source. """
[docs] @abc.abstractmethod def get_min_max_mag(self): """ Return minimum and maximum magnitudes of the ruptures generated by the source. """
[docs] def modify(self, modification, parameters): """ Apply a single modificaton to the source parameters Reflects the modification method and calls it passing ``parameters`` as keyword arguments. Modifications can be applied one on top of another. The logic of stacking modifications is up to a specific source implementation. :param modification: String name representing the type of modification. :param parameters: Dictionary of parameters needed for modification. :raises ValueError: If ``modification`` is missing from the attribute `MODIFICATIONS`. """ if modification not in self.MODIFICATIONS: raise ValueError('Modification %s is not supported by %s' % (modification, type(self).__name__)) meth = getattr(self, 'modify_%s' % modification) meth(**parameters)
[docs]@with_slots class ParametricSeismicSource(BaseSeismicSource, metaclass=abc.ABCMeta): """ Parametric Seismic Source generates earthquake ruptures from source parameters, and associated probabilities of occurrence are defined through a magnitude frequency distribution and a temporal occurrence model. :param mfd: Magnitude-Frequency distribution for the source. See :mod:`openquake.hazardlib.mfd`. :param rupture_mesh_spacing: The desired distance between two adjacent points in source's ruptures' mesh, in km. Mainly this parameter allows to balance the trade-off between time needed to compute the :meth:`distance <openquake.hazardlib.geo.surface.base.BaseSurface.get_min_distance>` between the rupture surface and a site and the precision of that computation. :param magnitude_scaling_relationship: Instance of subclass of :class:`openquake.hazardlib.scalerel.base.BaseMSR` to describe how does the area of the rupture depend on magnitude and rake. :param rupture_aspect_ratio: Float number representing how much source's ruptures are more wide than tall. Aspect ratio of 1 means ruptures have square shape, value below 1 means ruptures stretch vertically more than horizontally and vice versa. :param temporal_occurrence_model: Instance of :class:`openquake.hazardlib.tom.PoissonTOM` defining temporal occurrence model for calculating rupture occurrence probabilities :raises ValueError: If either rupture aspect ratio or rupture mesh spacing is not positive (if not None). """ _slots_ = BaseSeismicSource._slots_ + '''mfd rupture_mesh_spacing magnitude_scaling_relationship rupture_aspect_ratio temporal_occurrence_model'''.split() def __init__(self, source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model): super().__init__(source_id, name, tectonic_region_type) if rupture_mesh_spacing is not None and not rupture_mesh_spacing > 0: raise ValueError('rupture mesh spacing must be positive') if rupture_aspect_ratio is not None and not rupture_aspect_ratio > 0: raise ValueError('rupture aspect ratio must be positive') self.mfd = mfd self.rupture_mesh_spacing = rupture_mesh_spacing self.magnitude_scaling_relationship = magnitude_scaling_relationship self.rupture_aspect_ratio = rupture_aspect_ratio self.temporal_occurrence_model = temporal_occurrence_model
[docs] def get_annual_occurrence_rates(self, min_rate=0): """ Get a list of pairs "magnitude -- annual occurrence rate". The list is taken from assigned MFD object (see :meth:`openquake.hazardlib.mfd.base.BaseMFD.get_annual_occurrence_rates`) with simple filtering by rate applied. :param min_rate: A non-negative value to filter magnitudes by minimum annual occurrence rate. Only magnitudes with rates greater than that are included in the result list. :returns: A list of two-item tuples -- magnitudes and occurrence rates. """ return [(mag, occ_rate) for (mag, occ_rate) in self.mfd.get_annual_occurrence_rates() if (min_rate is None or occ_rate > min_rate) and mag >= self.min_mag]
[docs] def get_min_max_mag(self): """ Get the minimum and maximum magnitudes of the ruptures generated by the source from the underlying MFD. """ return self.mfd.get_min_max_mag()
def __repr__(self): """ String representation of a source, displaying the source class name and the source id. """ return '<%s %s>' % (self.__class__.__name__, self.source_id)