openquake.hazardlib.calc package¶
Hazardlib calculators¶
Disaggregation (disagg)¶
openquake.hazardlib.calc.disagg
contains
disaggregation()
as well as several aggregation functions for
extracting a specific PMF from the result of disaggregation()
.

openquake.hazardlib.calc.disagg.
build_disagg_matrix
(bdata, bin_edges, sid, mon=<class 'openquake.baselib.performance.Monitor'>)[source]¶  Parameters
bdata – a dictionary of probabilities of no exceedence
bin_edges – bin edges
sid – site index
mon – a Monitor instance
 Returns
a dictionary key > matrixpmf for each key in bdata

openquake.hazardlib.calc.disagg.
collect_bin_data
(ruptures, sitecol, cmaker, iml4, truncation_level, n_epsilons, monitor=<Monitor [ubuntu]>)[source]¶  Parameters
ruptures – a list of ruptures
sitecol – a SiteCollection instance
cmaker – a ContextMaker instance
iml4 – an ArrayWrapper of intensities of shape (N, R, M, P)
truncation_level – the truncation level
n_epsilons – the number of epsilons
monitor – a Monitor instance
 Returns
a dictionary (poe, imt, rlzi) > probabilities of shape (N, E)

openquake.hazardlib.calc.disagg.
disaggregation
(sources, site, imt, iml, gsim_by_trt, truncation_level, n_epsilons, mag_bin_width, dist_bin_width, coord_bin_width, source_filter=<openquake.hazardlib.calc.filters.SourceFilter object>, filter_distance='rjb')[source]¶ Compute “Disaggregation” matrix representing conditional probability of an intensity mesaure type
imt
exceeding, at least once, an intensity measure leveliml
at a geographical locationsite
, given rupture scenarios classified in terms of:rupture magnitude
JoynerBoore distance from rupture surface to site
longitude and latitude of the surface projection of a rupture’s point closest to
site
epsilon: number of standard deviations by which an intensity measure level deviates from the median value predicted by a GSIM, given the rupture parameters
rupture tectonic region type
In other words, the disaggregation matrix allows to compute the probability of each scenario with the specified properties (e.g., magnitude, or the magnitude and distance) to cause one or more exceedences of a given hazard level.
For more detailed information about the disaggregation, see for instance “Disaggregation of Seismic Hazard”, Paolo Bazzurro, C. Allin Cornell, Bulletin of the Seismological Society of America, Vol. 89, pp. 501520, April 1999.
 Parameters
sources – Seismic source model, as for
PSHA
calculator it should be an iterator of seismic sources.site –
Site
of interest to calculate disaggregation matrix for.imt – Instance of
intensity measure type
class.iml – Intensity measure level. A float value in units of
imt
.gsim_by_trt – Tectonic region type to GSIM objects mapping.
truncation_level – Float, number of standard deviations for truncation of the intensity distribution.
n_epsilons – Integer number of epsilon histogram bins in the result matrix.
mag_bin_width – Magnitude discretization step, width of one magnitude histogram bin.
dist_bin_width – Distance histogram discretization step, in km.
coord_bin_width – Longitude and latitude histograms discretization step, in decimal degrees.
source_filter – Optional sourcesite filter function. See
openquake.hazardlib.calc.filters
.
 Returns
A tuple of two items. First is itself a tuple of bin edges information for (in specified order) magnitude, distance, longitude, latitude, epsilon and tectonic region types.
Second item is 6darray representing the full disaggregation matrix. Dimensions are in the same order as bin edges in the first item of the result tuple. The matrix can be used directly by pmfextractor functions.

openquake.hazardlib.calc.disagg.
dist_pmf
(matrix)[source]¶ Fold full disaggregation matrix to distance PMF.
 Returns
1d array, a histogram representing distance PMF.

openquake.hazardlib.calc.disagg.
get_shape
(bin_edges, sid)[source]¶  Returns
the shape of the disaggregation matrix for the given site, of form (#mags1, #dists1, #lons1, #lats1, #eps1)

openquake.hazardlib.calc.disagg.
lon_lat_bins
(bb, coord_bin_width)[source]¶ Define bin edges for disaggregation histograms.
Given bins data as provided by
collect_bin_data()
, this function finds edges of histograms, taking into account maximum and minimum values of magnitude, distance and coordinates as well as requested sizes/numbers of bins.

openquake.hazardlib.calc.disagg.
lon_lat_pmf
(matrix)[source]¶ Fold full disaggregation matrix to longitude / latitude PMF.
 Returns
2d array. First dimension represents longitude histogram bins, second one – latitude histogram bins.

openquake.hazardlib.calc.disagg.
lon_lat_trt_pmf
(matrices)[source]¶ Fold full disaggregation matrices to lon / lat / TRT PMF.
 Parameters
matrices – a matrix with T submatrices
 Returns
3d array. First dimension represents longitude histogram bins, second one latitude histogram bins, third one trt histogram bins.

openquake.hazardlib.calc.disagg.
mag_dist_eps_pmf
(matrix)[source]¶ Fold full disaggregation matrix to magnitude / distance / epsilon PMF.
 Returns
3d array. First dimension represents magnitude histogram bins, second one – distance histogram bins, third one – epsilon histogram bins.

openquake.hazardlib.calc.disagg.
mag_dist_pmf
(matrix)[source]¶ Fold full disaggregation matrix to magnitude / distance PMF.
 Returns
2d array. First dimension represents magnitude histogram bins, second one – distance histogram bins.

openquake.hazardlib.calc.disagg.
mag_lon_lat_pmf
(matrix)[source]¶ Fold full disaggregation matrix to magnitude / longitude / latitude PMF.
 Returns
3d array. First dimension represents magnitude histogram bins, second one – longitude histogram bins, third one – latitude histogram bins.

openquake.hazardlib.calc.disagg.
mag_pmf
(matrix)[source]¶ Fold full disaggregation matrix to magnitude PMF.
 Returns
1d array, a histogram representing magnitude PMF.
Filters (filters)¶

class
openquake.hazardlib.calc.filters.
IntegrationDistance
(dic)[source]¶ Bases:
collections.abc.Mapping
Pickleable object wrapping a dictionary of integration distances per tectonic region type. The integration distances can be scalars or list of pairs (magnitude, distance). Here is an example using ‘default’ as tectonic region type, so that the same values will be used for all tectonic region types:
>>> maxdist = IntegrationDistance({'default': [ ... (3, 30), (4, 40), (5, 100), (6, 200), (7, 300), (8, 400)]}) >>> maxdist('Some TRT', mag=2.5) 30 >>> maxdist('Some TRT', mag=3) 30 >>> maxdist('Some TRT', mag=3.1) 40 >>> maxdist('Some TRT', mag=8) 400 >>> maxdist('Some TRT', mag=8.5) # 2000 km are used above the maximum 2000

get_affected_box
(src)[source]¶ Get the enlarged bounding box of a source.
 Parameters
src – a source object
 Returns
a bounding box (min_lon, min_lat, max_lon, max_lat)

get_bounding_box
(lon, lat, trt=None, mag=None)[source]¶ Build a bounding box around the given lon, lat by computing the maximum_distance at the given tectonic region type and magnitude.
 Parameters
lon – longitude
lat – latitude
trt – tectonic region type, possibly None
mag – magnitude, possibly None
 Returns
min_lon, min_lat, max_lon, max_lat


class
openquake.hazardlib.calc.filters.
Piecewise
(x, y)[source]¶ Bases:
object
Given two arrays x and y of nondecreasing values, build a piecewise function associating to each x the corresponding y. If x is smaller then the minimum x, the minimum y is returned; if x is larger than the maximum x, the maximum y is returned.

class
openquake.hazardlib.calc.filters.
SourceFilter
(sitecol, integration_distance, filename=None)[source]¶ Bases:
object
Filter objects have a .filter method yielding filtered sources, i.e. sources with an attribute .indices, containg the IDs of the sites within the given maximum distance. There is also a .new method that filters the sources in parallel and returns a dictionary src_group_id > filtered sources. Filter the sources by using self.sitecol.within_bbox which is based on numpy.

close_sids
(rec, trt, mag)[source]¶  Parameters
rec – a record with fields minlon, minlat, maxlon, maxlat
trt – tectonic region type string
mag – magnitude
 Returns
the site indices within the bounding box enlarged by the integration distance for the given TRT and magnitude

get_bounding_boxes
(trt=None, mag=None)[source]¶  Parameters
trt – a tectonic region type (used for the integration distance)
mag – a magnitude (used for the integration distance)
 Returns
a list of bounding boxes, one per site

get_close_sites
(source)[source]¶ Returns the sites within the integration distance from the source, or None.

get_rectangle
(src)[source]¶  Parameters
src – a source object
 Returns
((min_lon, min_lat), width, height), useful for plotting

sitecol
¶ Read the site collection from .filename and cache it


openquake.hazardlib.calc.filters.
context
(src)[source]¶ Used to add the source_id to the error message. To be used as
 with context(src):
operation_with(src)
Typically the operation is filtering a source, that can fail for tricky geometries.
Ground Motion Fields (gmf)¶
Module gmf
exports
ground_motion_fields()
.

exception
openquake.hazardlib.calc.gmf.
CorrelationButNoInterIntraStdDevs
(corr, gsim)[source]¶ Bases:
Exception

class
openquake.hazardlib.calc.gmf.
GmfComputer
(rupture, sitecol, imts, cmaker, truncation_level=None, correlation_model=None)[source]¶ Bases:
object
Given an earthquake rupture, the ground motion field computer computes ground shaking over a set of sites, by randomly sampling a ground shaking intensity model.
 Parameters
rupture – Rupture to calculate ground motion fields radiated from.
 :param
openquake.hazardlib.site.SiteCollection
sitecol: a complete SiteCollection
 Parameters
imts – a sorted list of Intensity Measure Type strings
cmaker – a
openquake.hazardlib.gsim.base.ContextMaker
instancetruncation_level – Float, number of standard deviations for truncation of the intensity distribution, or
None
.correlation_model – Instance of correlation model object. See
openquake.hazardlib.correlation
. Can beNone
, in which case noncorrelated ground motion fields are calculated. Correlation model is not used iftruncation_level
is zero.

compute
(gsim, num_events, seed=None)[source]¶  Parameters
gsim – a GSIM instance
num_events – the number of seismic events
seed – a random seed or None
 Returns
a 32 bit array of shape (num_imts, num_sites, num_events) and two arrays with shape (num_imts, num_events): sig for stddev_inter and eps for the random part

openquake.hazardlib.calc.gmf.
ground_motion_fields
(rupture, sites, imts, gsim, truncation_level, realizations, correlation_model=None, seed=None)[source]¶ Given an earthquake rupture, the ground motion field calculator computes ground shaking over a set of sites, by randomly sampling a ground shaking intensity model. A ground motion field represents a possible ‘realization’ of the ground shaking due to an earthquake rupture.
Note
This calculator is using random numbers. In order to reproduce the same results numpy random numbers generator needs to be seeded, see http://docs.scipy.org/doc/numpy/reference/generated/numpy.random.seed.html
 Parameters
rupture (openquake.hazardlib.source.rupture.Rupture) – Rupture to calculate ground motion fields radiated from.
sites (openquake.hazardlib.site.SiteCollection) – Sites of interest to calculate GMFs.
imts – List of intensity measure type objects (see
openquake.hazardlib.imt
).gsim – Groundshaking intensity model, instance of subclass of either
GMPE
orIPE
.truncation_level – Float, number of standard deviations for truncation of the intensity distribution, or
None
.realizations – Integer number of GMF realizations to compute.
correlation_model – Instance of correlation model object. See
openquake.hazardlib.correlation
. Can beNone
, in which case noncorrelated ground motion fields are calculated. Correlation model is not used iftruncation_level
is zero.seed (int) – The seed used in the numpy random number generator
 Returns
Dictionary mapping intensity measure type objects (same as in parameter
imts
) to 2d numpy arrays of floats, representing different realizations of ground shaking intensity for all sites in the collection. First dimension represents sites and second one is for realizations.
Hazard Curves (hazard_curve)¶
openquake.hazardlib.calc.hazard_curve
implements
calc_hazard_curves()
. Here is an example of a classical PSHA
parallel calculator computing the hazard curves per each realization in less
than 20 lines of code:
import sys
import logging
from openquake.baselib import parallel
from openquake.hazardlib.calc.filters import SourceFilter
from openquake.hazardlib.calc.hazard_curve import calc_hazard_curves
from openquake.commonlib import readinput
def main(job_ini):
logging.basicConfig(level=logging.INFO)
oq = readinput.get_oqparam(job_ini)
sitecol = readinput.get_site_collection(oq)
src_filter = SourceFilter(sitecol, oq.maximum_distance)
csm = readinput.get_composite_source_model(oq, srcfilter=src_filter)
rlzs_assoc = csm.info.get_rlzs_assoc()
for i, sm in enumerate(csm.source_models):
for rlz in rlzs_assoc.rlzs_by_smodel[i]:
gsim_by_trt = rlzs_assoc.gsim_by_trt[rlz.ordinal]
hcurves = calc_hazard_curves(
sm.src_groups, src_filter, oq.imtls,
gsim_by_trt, oq.truncation_level,
parallel.Starmap.apply)
print('rlz=%s, hcurves=%s' % (rlz, hcurves))
if __name__ == '__main__':
main(sys.argv[1]) # path to a job.ini file
NB: the implementation in the engine is smarter and more efficient. Here we start a parallel computation per each realization, the engine manages all the realizations at once.

openquake.hazardlib.calc.hazard_curve.
calc_hazard_curves
(groups, ss_filter, imtls, gsim_by_trt, truncation_level=None, apply=<function sequential_apply>, filter_distance='rjb', reqv=None)[source]¶ Compute hazard curves on a list of sites, given a set of seismic source groups and a dictionary of ground shaking intensity models (one per tectonic region type).
Probability of ground motion exceedance is computed in different ways depending if the sources are independent or mutually exclusive.
 Parameters
groups – A sequence of groups of seismic sources objects (instances of of
BaseSeismicSource
).ss_filter – A source filter over the site collection or the site collection itself
imtls – Dictionary mapping intensity measure type strings to lists of intensity measure levels.
gsim_by_trt – Dictionary mapping tectonic region types (members of
openquake.hazardlib.const.TRT
) toGMPE
orIPE
objects.truncation_level – Float, number of standard deviations for truncation of the intensity distribution.
apply – apply function to use (default sequential_apply)
filter_distance – The distance used to filter the ruptures (default rjb)
reqv – If not None, an instance of RjbEquivalent
 Returns
An array of size N, where N is the number of sites, which elements are records with fields given by the intensity measure types; the size of each field is given by the number of levels in
imtls
.

openquake.hazardlib.calc.hazard_curve.
classical
(group, src_filter, gsims, param, monitor=<Monitor [ubuntu]>)[source]¶ Compute the hazard curves for a set of sources belonging to the same tectonic region type for all the GSIMs associated to that TRT. The arguments are the same as in
calc_hazard_curves()
, except forgsims
, which is a list of GSIM instances. Returns
a dictionary {grp_id: pmap} with attributes .grp_ids, .calc_times, .eff_ruptures
Stochastic Event Set (stochastic)¶
openquake.hazardlib.calc.stochastic
contains
stochastic_event_set()
.

openquake.hazardlib.calc.stochastic.
get_rup_array
(ebruptures, srcfilter=<openquake.hazardlib.calc.filters.SourceFilter object>)[source]¶ Convert a list of EBRuptures into a numpy composite array, by filtering out the ruptures far away from every site

openquake.hazardlib.calc.stochastic.
sample_cluster
(sources, srcfilter, num_ses, param)[source]¶ Yields ruptures generated by a cluster of sources.
 Parameters
sources – A sequence of sources of the same group
num_ses – Number of stochastic event sets
param – a dictionary of additional parameters including ses_per_logic_tree_path
 Yields
dictionaries with keys rup_array, calc_times, eff_ruptures

openquake.hazardlib.calc.stochastic.
sample_ruptures
(sources, srcfilter, param, monitor=<Monitor [ubuntu]>)[source]¶  Parameters
sources – a sequence of sources of the same group
srcfilter – SourceFilter instance used also for bounding box post filtering
param – a dictionary of additional parameters including ses_per_logic_tree_path
monitor – monitor instance
 Yields
dictionaries with keys rup_array, calc_times, eff_ruptures

openquake.hazardlib.calc.stochastic.
stochastic_event_set
(sources, source_site_filter=<openquake.hazardlib.calc.filters.SourceFilter object>)[source]¶ Generates a ‘Stochastic Event Set’ (that is a collection of earthquake ruptures) representing a possible realization of the seismicity as described by a source model.
The calculator loops over sources. For each source, it loops over ruptures. For each rupture, the number of occurrence is randomly sampled by calling
openquake.hazardlib.source.rupture.BaseProbabilisticRupture.sample_number_of_occurrences()
Note
This calculator is using random numbers. In order to reproduce the same results numpy random numbers generator needs to be seeded, see http://docs.scipy.org/doc/numpy/reference/generated/numpy.random.seed.html
 Parameters
sources – An iterator of seismic sources objects (instances of subclasses of
BaseSeismicSource
).source_site_filter – The source filter to use (default noop filter)
 Returns
Generator of
Rupture
objects that are contained in an event set. Some ruptures can be missing from it, others can appear one or more times in a row.