class MomentTensor(force_resource_id=True, *args, **kwargs)[source]

Bases: obspy.core.event.base.__MomentTensor

This class represents a moment tensor solution for an event. It is an optional part of a FocalMechanism description.

  • resource_id (ResourceIdentifier) Resource identifier of MomentTensor.
  • force_resource_id (bool, optional) If set to False, the automatic initialization of resource_id attribute in case it is not specified will be skipped.
  • derived_origin_id (ResourceIdentifier) Refers to the resource_id of the Origin derived in the moment tensor inversion.
  • moment_magnitude_id (ResourceIdentifier, optional) Refers to the publicID of the Magnitude object which represents the derived moment magnitude.
  • scalar_moment (float, optional) Scalar moment as derived in moment tensor inversion. Unit: Nm
  • scalar_moment_errors (QuantityError) AttribDict containing error quantities.
  • tensor (Tensor, optional) Tensor object holding the moment tensor elements.
  • variance (float, optional) Variance of moment tensor inversion.
  • variance_reduction (float, optional) Variance reduction of moment tensor inversion, given in percent (Dreger 2003). This is a goodness-of-fit measure.
  • double_couple (float, optional) Double couple parameter obtained from moment tensor inversion (decimal fraction between 0 and 1).
  • clvd (float, optional) CLVD (compensated linear vector dipole) parameter obtained from moment tensor inversion (decimal fraction between 0 and 1).
  • iso (float, optional) Isotropic part obtained from moment tensor inversion (decimal fraction between 0 and 1).
  • greens_function_id (ResourceIdentifier, optional) Resource identifier of the Green’s function used in moment tensor inversion.
  • filter_id (ResourceIdentifier, optional) Resource identifier of the filter setup used in moment tensor inversion.
  • source_time_function (SourceTimeFunction, optional) Source time function used in moment-tensor inversion.
  • data_used (list of DataUsed, optional) Describes waveform data used for moment-tensor inversion.
  • method_id (ResourceIdentifier, optional) Resource identifier of the method used for moment-tensor inversion.
  • category (str, optional) Moment tensor category. See MomentTensorCategory for allowed values.
  • inversion_type (str, optional) Moment tensor inversion type. Users should avoid to give contradictory information in inversion_type and method_id. See MTInversionType for allowed values.
  • comments (list of Comment, optional) Additional comments.
  • creation_info (CreationInfo, optional) Creation information used to describe author, version, and creation time.


For handling additional information not covered by the QuakeML standard and how to output it to QuakeML see the ObsPy Tutorial.


__abstractmethods__ frozenset() -> empty frozenset object
__doc__ str(object=’‘) -> str
__module__ str(object=’‘) -> str
__slots__ tuple() -> empty tuple
__weakref__ list of weak references to the object (if defined)
defaults dict() -> new empty dictionary
do_not_warn_on list() -> new empty list
item tuple() -> empty tuple
key str(object=’‘) -> str
readonly list() -> new empty list
warn_on_non_default_key bool(x) -> bool

Public Methods

pop If key is not found, d is returned if given, otherwise KeyError is raised.
popitem as a 2-tuple; but raise KeyError if D is empty.

Private Methods


Private methods are mainly for internal/developer use and their API might change without notice.

_pretty_str Return better readable string representation of AttribDict object.

Special Methods

__dir__ default dir() implementation
__eq__ Two instances are considered equal if all attributes and all lists
__format__ default object formatter
__getattr__ Py3k hasattr() expects an AttributeError no KeyError to be
__new__ Create and return a new object.
__reduce__ helper for pickle
__reduce_ex__ helper for pickle
__setattr__ Custom property implementation that works if the class is
__sizeof__ size of object in memory, in bytes
__str__ Fairly extensive in an attempt to cover several use cases.