openquake.hazardlib.source package

Seismic sources and ruptures

area

Module openquake.hazardlib.source.area defines AreaSource.

class openquake.hazardlib.source.area.AreaSource(source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model, upper_seismogenic_depth, lower_seismogenic_depth, nodal_plane_distribution, hypocenter_distribution, polygon, area_discretization)[source]

Bases: openquake.hazardlib.source.base.ParametricSeismicSource

Area source represents uniform seismicity occurring over a geographical region.

Parameters:

Other parameters (except location) are the same as for PointSource.

MODIFICATIONS = set()
RUPTURE_WEIGHT = 0.1
assert_equal(other, ignore=())
count_ruptures()[source]

See openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures() for description of parameters and return value.

iter_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.iter_ruptures for description of parameters and return value.

Area sources are treated as a collection of point sources (see openquake.hazardlib.source.point) with uniform parameters. Ruptures of area source are just a union of ruptures of those point sources. The actual positions of the implied point sources form a uniformly spaced mesh on the polygon. Polygon’s method :meth: ~openquake.hazardlib.geo.polygon.Polygon.discretize is used for creating a mesh of points on the source’s area. Constructor’s parameter area_discretization is used as polygon’s discretization spacing (not to be confused with rupture surface’s mesh spacing which is as well provided to the constructor).

The ruptures’ occurrence rates are rescaled with respect to number of points the polygon discretizes to.

base

Module openquake.hazardlib.source.base defines a base class for seismic sources.

class openquake.hazardlib.source.base.BaseSeismicSource(source_id, name, tectonic_region_type)[source]

Bases: object

Base class representing a seismic source, that is a structure generating earthquake ruptures.

Parameters:
  • source_id – Some (numeric or literal) source identifier. Supposed to be unique within the source model.
  • name – String, a human-readable name of the source.
  • tectonic_region_type – Source’s tectonic regime. See openquake.hazardlib.const.TRT.
MODIFICATIONS
RUPTURE_WEIGHT = 1.0
assert_equal(other, ignore=())
count_ruptures()[source]

Return the number of ruptures that will be generated by the source.

get_min_max_mag()[source]

Return minimum and maximum magnitudes of the ruptures generated by the source.

iter_ruptures()[source]

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.
modify(modification, parameters)[source]

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.

Parameters:
  • modification – String name representing the type of modification.
  • parameters – Dictionary of parameters needed for modification.
Raises:

ValueError – If modification is missing from the attribute MODIFICATIONS.
ngsims = 1
nsites
Returns:the number of sites affected by this source
src_group_ids
Returns:a list of source group IDs (usually of 1 element)
weight

Determine the source weight from the number of ruptures, by multiplying with the scale factor RUPTURE_WEIGHT

class openquake.hazardlib.source.base.ParametricSeismicSource(source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model)[source]

Bases: openquake.hazardlib.source.base.BaseSeismicSource

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.

Parameters:
  • mfd – Magnitude-Frequency distribution for the source. See openquake.hazardlib.mfd.
  • 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 distance between the rupture surface and a site and the precision of that computation.
  • magnitude_scaling_relationship – Instance of subclass of openquake.hazardlib.scalerel.base.BaseMSR to describe how does the area of the rupture depend on magnitude and rake.
  • 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.
  • temporal_occurrence_model – Instance of 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).
assert_equal(other, ignore=())
get_annual_occurrence_rates(min_rate=0)[source]

Get a list of pairs “magnitude – annual occurrence rate”.

The list is taken from assigned MFD object (see openquake.hazardlib.mfd.base.BaseMFD.get_annual_occurrence_rates()) with simple filtering by rate applied.

Parameters: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.
get_min_max_mag()[source]

Get the minimum and maximum magnitudes of the ruptures generated by the source from the underlying MFD.

characteristic

Module openquake.hazardlib.source.characteristic defines CharacteristicFaultSource.

class openquake.hazardlib.source.characteristic.CharacteristicFaultSource(source_id, name, tectonic_region_type, mfd, temporal_occurrence_model, surface, rake, surface_node=None)[source]

Bases: openquake.hazardlib.source.base.ParametricSeismicSource

Characteristic source typology represents seismicity occuring on a generic fault surface with seismic events rupturing the entire fault surface independently of their magnitude values.

Characteristic source typology can be used to model individual faults or fault segments that tend to produce essentialy same size earthquakes (see for instance: Schwartz, D. P., K. J. Coppersmith, Fault behavior and characteristic earthquakes: Examples from the Wasatch and San Andreas fault zones, J. Geophys. Res., 89, 5681-5698, 1984)

Parameters:

See also openquake.hazardlib.source.base.ParametricSeismicSource for description of other parameters.

Note that a CharacteristicFaultSource does not need any mesh spacing, magnitude scaling relationship, and aspect ratio, therefore the constructor sets these parameters to None.

NB: if you want to convert a characteristic source into XML, you must set its attribute surface_node to an explicit representation of the surface as a LiteralNode object.

MODIFICATIONS = {'set_geometry'}
assert_equal(other, ignore=())
count_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures.

get_bounding_box(maxdist)[source]

Bounding box containing all points, enlarged by the maximum distance

iter_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.iter_ruptures.

For each magnitude value in the given MFD, return an earthquake rupture with a surface always equal to the given surface.

modify_set_geometry(surface, surface_node=None)[source]

Modifies the current fault geometry

Parameters:
polygon

The underlying polygon, as a convex hull

complex_fault

Module openquake.hazardlib.source.complex_fault defines ComplexFaultSource.

class openquake.hazardlib.source.complex_fault.ComplexFaultSource(source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model, edges, rake)[source]

Bases: openquake.hazardlib.source.base.ParametricSeismicSource

Complex fault source typology represents seismicity occurring on a fault surface with an arbitrarily complex geometry.

Parameters:

See also openquake.hazardlib.source.base.ParametricSeismicSource for description of other parameters.

Raises:ValueError – If check_fault_data() fails or if rake value is invalid.
MODIFICATIONS = {'set_geometry'}
RUPTURE_WEIGHT = 4.0
assert_equal(other, ignore=())
count_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures.

iter_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.iter_ruptures.

Uses _float_ruptures() for finding possible rupture locations on the whole fault surface.

modify_set_geometry(edges, spacing)[source]

Modifies the complex fault geometry

polygon

The underlying polygon `

start = None
stop = None
openquake.hazardlib.source.complex_fault.split(src, chunksize=100)[source]

Split a complex fault source in chunks of at most MAXWEIGHT ruptures

non_parametric

Module openquake.hazardlib.source.non_parametric defines NonParametricSeismicSource

class openquake.hazardlib.source.non_parametric.NonParametricSeismicSource(source_id, name, tectonic_region_type, data)[source]

Bases: openquake.hazardlib.source.base.BaseSeismicSource

Non Parametric Seismic Source explicitly defines earthquake ruptures in the constructor. That is earthquake ruptures are not generated algorithmically from a set of source parameters.

Ruptures’ rectonic region types are overwritten by source tectonic region type.

Parameters:data – List of tuples. Each tuple must contain two items. The first item must be an instance of openquake.hazardlib.source.rupture.Rupture. The second item must be an instance of openquake.hazardlib.pmf.PMF describing the probability of the rupture to occur N times (the PMF must be defined from a minimum number of occurrences equal to 0)
MODIFICATIONS = set()
assert_equal(other, ignore=())
count_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures.

get_bounding_box(maxdist)[source]

Bounding box containing all surfaces, enlarged by the maximum distance

get_min_max_mag()[source]

Return the minimum and maximum magnitudes of the ruptures generated by the source

iter_ruptures()[source]

Get a generator object that yields probabilistic ruptures the source consists of.

Returns:Generator of instances of :class: ~openquake.hazardlib.source.rupture.NonParametricProbabilisticRupture.

point

Module openquake.hazardlib.source.point defines PointSource.

class openquake.hazardlib.source.point.PointSource(source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model, upper_seismogenic_depth, lower_seismogenic_depth, location, nodal_plane_distribution, hypocenter_distribution)[source]

Bases: openquake.hazardlib.source.base.ParametricSeismicSource

Point source typology represents seismicity on a single geographical location.

Parameters:
  • upper_seismogenic_depth – Minimum depth an earthquake rupture can reach, in km.
  • lower_seismogenic_depth – Maximum depth an earthquake rupture can reach, in km.
  • location – Point object representing the location of the seismic source.
  • nodal_plane_distribution – PMF object with values that are instances of openquake.hazardlib.geo.nodalplane.NodalPlane. Shows the distribution of probability for rupture to have the certain nodal plane.
  • hypocenter_distribution – PMF with values being float numbers in km representing the depth of the hypocenter. Latitude and longitude of the hypocenter is always set to ones of location.

See also openquake.hazardlib.source.base.ParametricSeismicSource for description of other parameters.

Raises:ValueError – If upper seismogenic depth is below lower seismogenic depth, if one or more of hypocenter depth values is shallower than upper seismogenic depth or deeper than lower seismogenic depth.
MODIFICATIONS = set()
RUPTURE_WEIGHT = 0.1
assert_equal(other, ignore=())
count_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures.

get_bounding_box(maxdist)[source]

Bounding box containing all points, enlarged by the maximum distance and the maximum rupture projection radius (upper limit).

iter_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.iter_ruptures.

Generate one rupture for each combination of magnitude, nodal plane and hypocenter depth.

polygon

Polygon corresponding to the max_rupture_projection_radius

rupture

Module openquake.hazardlib.source.rupture defines classes BaseRupture and its subclasses NonParametricProbabilisticRupture and ParametricProbabilisticRupture

class openquake.hazardlib.source.rupture.BaseRupture(mag, rake, tectonic_region_type, hypocenter, surface, rupture_slip_direction=None)[source]

Bases: object

Rupture object represents a single earthquake rupture.

Parameters:
  • mag – Magnitude of the rupture.
  • rake – Rake value of the rupture. See NodalPlane.
  • tectonic_region_type – Rupture’s tectonic regime. One of constants in openquake.hazardlib.const.TRT.
  • hypocenter – A Point, rupture’s hypocenter.
  • surface – An instance of subclass of BaseSurface. Object representing the rupture surface geometry.
  • rupture_slip_direction – Angle describing rupture propagation direction in decimal degrees.
Raises:

ValueError – If magnitude value is not positive, or tectonic region type is unknown.

NB: if you want to convert the rupture into XML, you should set the attribute surface_nodes to an appropriate value.

assert_equal(other, ignore=())
code

Returns the code (integer in the range 0 .. 255) of the rupture

get_probability_no_exceedance(poes)[source]

Compute and return the probability that in the time span for which the rupture is defined, the rupture itself never generates a ground motion value higher than a given level at a given site.

Such calculation is performed starting from the conditional probability that an occurrence of the current rupture is producing a ground motion value higher than the level of interest at the site of interest. The actual formula used for such calculation depends on the temporal occurrence model the rupture is associated with. The calculation can be performed for multiple intensity measure levels and multiple sites in a vectorized fashion.

Parameters:poes – 2D numpy array containing conditional probabilities the the a rupture occurrence causes a ground shaking value exceeding a ground motion level at a site. First dimension represent sites, second dimension intensity measure levels. poes can be obtained calling the method.
classmethod init()[source]

Initialize the class dictionaries ._code and .`types` encoding the bidirectional correspondence between an integer in the range 0..255 (the code) and a triplet of classes (rupture_class, surface_class, source_class). This is useful when serializing the rupture to and from HDF5.

sample_number_of_occurrences()[source]

Randomly sample number of occurrences from temporal occurrence model probability distribution.

Note

This method 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

Returns:int, Number of rupture occurrences
serial = 0
types = {}
class openquake.hazardlib.source.rupture.EBRupture(rupture, sids, events)[source]

Bases: object

An event based rupture. It is a wrapper over a hazardlib rupture object, containing an array of site indices affected by the rupture, as well as the IDs of the corresponding seismic events.

eids

An array with the underlying event IDs

export(mesh)[source]

Yield Rupture objects, with all the attributes set, suitable for export in XML format.

grp_id

Group ID of the rupture

multiplicity

How many times the underlying rupture occurs.

serial

Serial number of the rupture

weight

Weight of the EBRupture

class openquake.hazardlib.source.rupture.ExportedRupture(rupid, events_by_ses, indices=None)[source]

Bases: object

Simplified Rupture class with attributes rupid, events_by_ses, indices and others, used in export.

Parameters:
  • rupid – rupture serial ID
  • events_by_ses – dictionary ses_idx -> event records
  • indices – site indices
class openquake.hazardlib.source.rupture.NonParametricProbabilisticRupture(mag, rake, tectonic_region_type, hypocenter, surface, pmf, rupture_slip_direction=None)[source]

Bases: openquake.hazardlib.source.rupture.BaseRupture

Probabilistic rupture for which the probability distribution for rupture occurrence is described through a generic probability mass function.

Parameters:pmf –

Instance of openquake.hazardlib.pmf.PMF. Values in the abscissae represent number of rupture occurrences (in increasing order, staring from 0) and values in the ordinates represent associated probabilities. Example: if, for a given time span, a rupture has probability 0.8 to not occurr, 0.15 to occur once, and 0.05 to occur twice, the pmf can be defined as

pmf = PMF([(0.8, 0), (0.15, 1), 0.05, 2)])
Raises:ValueError – If number of ruptures in pmf do not start from 0, are not defined in increasing order, and if they are not defined with unit step
get_probability_no_exceedance(poes)[source]

See superclass method for spec of input and result values.

Uses the formula

∑ p(k|T) * p(X<x|rup)^k

where p(k|T) is the probability that the rupture occurs k times in the time span T, p(X<x|rup) is the probability that a rupture occurrence does not cause a ground motion exceedance, and the summation ∑ is done over the number of occurrences k.

p(k|T) is given by the constructor’s parameter pmf, and p(X<x|rup) is computed as 1 - poes.

sample_number_of_occurrences()[source]

See superclass method for spec of input and result values.

Uses ‘Inverse Transform Sampling’ method.

class openquake.hazardlib.source.rupture.ParametricProbabilisticRupture(mag, rake, tectonic_region_type, hypocenter, surface, occurrence_rate, temporal_occurrence_model, rupture_slip_direction=None)[source]

Bases: openquake.hazardlib.source.rupture.BaseRupture

Rupture associated with an occurrence rate and a temporal occurrence model.

Parameters:
  • occurrence_rate – Number of times rupture happens per year.
  • temporal_occurrence_model – Temporal occurrence model assigned for this rupture. Should be an instance of openquake.hazardlib.tom.PoissonTOM.
Raises:

ValueError – If occurrence rate is not positive.
assert_equal(other, ignore=())
get_cdppvalue(target, buf=1.0, delta=0.01, space=2.0)[source]

Get the directivity prediction value, centered DPP(cdpp) at a given site as described in Spudich et al. (2013), and this cdpp is used in Chiou and Young (2014) GMPE for near-fault directivity term prediction.

Parameters:
  • target_site – A mesh object representing the location of the target sites.
  • buf – A buffer distance in km to extend the mesh borders
  • delta – The distance between two adjacent points in the mesh
  • space – The tolerance for the distance of the sites (default 2 km)
Returns:

The centered directivity prediction value of Chiou and Young
get_dppvalue(site)[source]

Get the directivity prediction value, DPP at a given site as described in Spudich et al. (2013).

Parameters:site – Point object representing the location of the target site
Returns:A float number, directivity prediction value (DPP).
get_probability_no_exceedance(poes)[source]

See superclass method for spec of input and result values.

Uses openquake.hazardlib.tom.PoissonTOM.get_probability_no_exceedance()

get_probability_one_occurrence()[source]

Return the probability of this rupture to occur exactly one time.

Uses :meth: openquake.hazardlib.tom.PoissonTOM.get_probability_one_occurrence of an assigned temporal occurrence model.

get_probability_one_or_more_occurrences()[source]

Return the probability of this rupture to occur one or more times.

Uses get_probability_one_or_more_occurrences() of an assigned temporal occurrence model.

sample_number_of_occurrences()[source]

Draw a random sample from the distribution and return a number of events to occur.

Uses :meth: openquake.hazardlib.tom.PoissonTOM.sample_number_of_occurrences of an assigned temporal occurrence model.

openquake.hazardlib.source.rupture.get_geom(surface, is_from_fault_source, is_multi_surface, is_gridded_surface)[source]

The following fields can be interpreted different ways, depending on the value of is_from_fault_source. If is_from_fault_source is True, each of these fields should contain a 2D numpy array (all of the same shape). Each triple of (lon, lat, depth) for a given index represents the node of a rectangular mesh. If is_from_fault_source is False, each of these fields should contain a sequence (tuple, list, or numpy array, for example) of 4 values. In order, the triples of (lon, lat, depth) represent top left, top right, bottom left, and bottom right corners of the the rupture’s planar surface. Update: There is now a third case. If the rupture originated from a characteristic fault source with a multi-planar-surface geometry, lons, lats, and depths will contain one or more sets of 4 points, similar to how planar surface geometry is stored (see above).

Parameters:
  • surface – a Surface instance
  • is_from_fault_source – a boolean
  • is_multi_surface – a boolean
openquake.hazardlib.source.rupture.get_subclasses(cls)[source]

simple_fault

Module openquake.hazardlib.source.simple_fault defines SimpleFaultSource.

class openquake.hazardlib.source.simple_fault.SimpleFaultSource(source_id, name, tectonic_region_type, mfd, rupture_mesh_spacing, magnitude_scaling_relationship, rupture_aspect_ratio, temporal_occurrence_model, upper_seismogenic_depth, lower_seismogenic_depth, fault_trace, dip, rake, hypo_list=(), slip_list=())[source]

Bases: openquake.hazardlib.source.base.ParametricSeismicSource

Simple fault source typology represents seismicity occurring on a fault surface with simple geometry.

Parameters:
  • upper_seismogenic_depth – Minimum depth an earthquake rupture can reach, in km.
  • lower_seismogenic_depth – Maximum depth an earthquake rupture can reach, in km.
  • fault_trace – A Line representing the line of intersection between the fault plane and the Earth’s surface.
  • dip – Angle between earth surface and fault plane in decimal degrees.
  • rake – the direction of hanging wall relative to the foot wall.
  • rupture_slip_direction – Angle describing rupture propagation direction in decimal degrees.
  • hypo_list – Array describing the relative position of the hypocentre on the rupture surface. Each line represents a hypocentral position defined in terms of the relative distance along strike and dip (from the upper, left corner of the fault surface i.e. the corner which results from the projection at depth of the first vertex of the fault trace) and the corresponding weight. Example 1: one single hypocentral position at the center of the rupture will be described by the following array[(0.5, 0.5, 1.0)]. Example 2: two possible hypocenters are admitted for a rupture. One hypocentre is located along the strike at 1/4 of the fault length and at 1/4 of the fault width along the dip and occurs with a weight of 0.3, the other one is at 3/4 of fault length along strike and at 3/4 of fault width along strike with a weight of 0.7. The numpy array would be entered as numpy.array([[0.25, 0.25, 0.3], [0.75, 0.75, 0.7]]).
  • slip_list – Array describing the rupture slip direction, which desribes the rupture propagation direction on the rupture surface. Each line represents a rupture slip direction and the corresponding weight. Example 1: one single rupture slip direction with angle 90 degree will be described by the following array[(90, 1.0)]. Example 2: two possible rupture slip directions are admitted for a rupture. One slip direction is at 90 degree with a weight of 0.7, the other one is at 135 degree with a weight of 0.3. The numpy array would be entered as numpy.array( [[90, 0.7], [135, 0.3]]).

See also openquake.hazardlib.source.base.ParametricSeismicSource for description of other parameters.

Raises:ValueError – If check_fault_data() fails, if rake value is invalid and if rupture mesh spacing is too high for the lowest magnitude value.
MODIFICATIONS = {'set_dip', 'set_geometry', 'adjust_dip'}
assert_equal(other, ignore=())
count_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.count_ruptures.

iter_ruptures()[source]

See :meth: openquake.hazardlib.source.base.BaseSeismicSource.iter_ruptures.

Generates a ruptures using the “floating” algorithm: for all the magnitude values of assigned MFD calculates the rupture size with respect to MSR and aspect ratio and then places ruptures of that size on the surface of the whole fault source. The occurrence rate of each of those ruptures is the magnitude occurrence rate divided by the number of ruptures that can be placed in a fault.

modify_adjust_dip(increment)[source]

Modifies the dip by an incremental value

Parameters:increment (float) – Value by which to increase or decrease the dip (the resulting dip must still be within 0.0 to 90.0 degrees)
modify_set_dip(dip)[source]

Modifies the dip to the specified value

Parameters:dip (float) – New value of dip (must still be within 0.0 to 90.0 degrees)
modify_set_geometry(fault_trace, upper_seismogenic_depth, lower_seismogenic_depth, dip, spacing)[source]

Modifies the current source geometry including trace, seismogenic depths and dip

polygon

The underlying polygon `