# Source code for openquake.hazardlib.calc.hazard_curve

```
# coding: utf-8
# The Hazard Library
# Copyright (C) 2012-2014, 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
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
:mod:`openquake.hazardlib.calc.hazard_curve` implements
:func:`hazard_curves`.
"""
import sys
import numpy
from openquake.hazardlib.calc import filters
from openquake.hazardlib.imt import from_string
from openquake.hazardlib.gsim.base import deprecated
@deprecated('Use calc_hazard_curves instead')
[docs]def hazard_curves(
sources, sites, imts, gsims, truncation_level,
source_site_filter=filters.source_site_noop_filter,
rupture_site_filter=filters.rupture_site_noop_filter):
"""
Deprecated. It does the same job of
:func:`openquake.hazardlib.calc.hazard_curve.calc_hazard_curves`,
with the only difference that the intensity measure types in input
and output are hazardlib objects instead of simple strings.
"""
imtls = {str(imt): imls for imt, imls in imts.iteritems()}
curves_by_imt = calc_hazard_curves(
sources, sites, imtls, gsims, truncation_level,
source_site_filter=filters.source_site_noop_filter,
rupture_site_filter=filters.rupture_site_noop_filter)
return {from_string(imt): curves
for imt, curves in curves_by_imt.iteritems()}
[docs]def calc_hazard_curves(
sources, sites, imtls, gsims, truncation_level,
source_site_filter=filters.source_site_noop_filter,
rupture_site_filter=filters.rupture_site_noop_filter):
"""
Compute hazard curves on a list of sites, given a set of seismic sources
and a set of ground shaking intensity models (one per tectonic region type
considered in the seismic sources).
Probability of ground motion exceedance is computed using the following
formula ::
P(X≥x|T) = 1 - ∏ ∏ Prup_ij(X<x|T)
where ``P(X≥x|T)`` is the probability that the ground motion parameter
``X`` is exceeding level ``x`` one or more times in a time span ``T``, and
``Prup_ij(X<x|T)`` is the probability that the j-th rupture of the i-th
source is not producing any ground motion exceedance in time span ``T``.
The first product ``∏`` is done over sources, while the second one is done
over ruptures in a source.
The above formula computes the probability of having at least one ground
motion exceedance in a time span as 1 minus the probability that none of
the ruptures in none of the sources is causing a ground motion exceedance
in the same time span. The basic assumption is that seismic sources are
independent, and ruptures in a seismic source are also independent.
:param sources:
An iterator of seismic sources objects (instances of subclasses
of :class:`~openquake.hazardlib.source.base.BaseSeismicSource`).
:param sites:
Instance of :class:`~openquake.hazardlib.site.SiteCollection` object,
representing sites of interest.
:param imtls:
Dictionary mapping intensity measure type strings
to lists of intensity measure levels.
:param gsims:
Dictionary mapping tectonic region types (members
of :class:`openquake.hazardlib.const.TRT`) to
:class:`~openquake.hazardlib.gsim.base.GMPE` or
:class:`~openquake.hazardlib.gsim.base.IPE` objects.
:param trunctation_level:
Float, number of standard deviations for truncation of the intensity
distribution.
:param source_site_filter:
Optional source-site filter function. See
:mod:`openquake.hazardlib.calc.filters`.
:param rupture_site_filter:
Optional rupture-site filter function. See
:mod:`openquake.hazardlib.calc.filters`.
:returns:
Dictionary mapping intensity measure type strings (same keys
as in parameter ``imtls``) to 2d numpy arrays of float, where
first dimension differentiates sites (the order and length
are the same as in ``sites`` parameter) and the second one
differentiates IMLs (the order and length are the same as
corresponding value in ``imts`` dict).
"""
imts = {from_string(imt): imls for imt, imls in imtls.iteritems()}
curves = dict((imt, numpy.ones([len(sites), len(imtls[imt])]))
for imt in imtls)
sources_sites = ((source, sites) for source in sources)
for source, s_sites in source_site_filter(sources_sites):
try:
ruptures_sites = ((rupture, s_sites)
for rupture in source.iter_ruptures())
for rupture, r_sites in rupture_site_filter(ruptures_sites):
gsim = gsims[rupture.tectonic_region_type]
sctx, rctx, dctx = gsim.make_contexts(r_sites, rupture)
for imt in imts:
poes = gsim.get_poes(sctx, rctx, dctx, imt, imts[imt],
truncation_level)
pno = rupture.get_probability_no_exceedance(poes)
curves[str(imt)] *= r_sites.expand(pno, placeholder=1)
except Exception, err:
etype, err, tb = sys.exc_info()
msg = 'An error occurred with source id=%s. Error: %s'
msg %= (source.source_id, err.message)
raise etype, msg, tb
for imt in imtls:
curves[imt] = 1 - curves[imt]
return curves
```