# obspy.core.event.source.MomentTensor

class `MomentTensor`(force_resource_id=True, *args, **kwargs)

  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.

  Parameters: | 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.

  Note

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

  Attributes

  `__abstractmethods__` | frozenset() -> empty frozenset object
  `__dict__` |
  `__doc__` | str(object=’‘) -> str
  `__hash__` |
  `__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

  `clear` |
  `copy` |
  `get` |
  `items` |
  `keys` |
  `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.
  `setdefault` |
  `update` |
  `values` |

  Private Methods

  Warning

  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.
  `_repr_pretty_` |

  Special Methods

  `__bool__` |
  `__contains__` |
  `__deepcopy__` | reset resource_id’s object_id after deep copy to allow the
  `__delattr__` |
  `__delitem__` |
  `__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
  `__getitem__` |
  `__getstate__` |
  `__init__` |
  `__iter__` |
  `__len__` |
  `__ne__` |
  `__new__` | Create and return a new object.
  `__nonzero__` |
  `__reduce__` | helper for pickle
  `__reduce_ex__` | helper for pickle
  `__repr__` |
  `__setattr__` | Custom property implementation that works if the class is
  `__setitem__` |
  `__setstate__` |
  `__sizeof__` | size of object in memory, in bytes
  `__str__` | Fairly extensive in an attempt to cover several use cases.
  `__subclasshook__` |

### Thank you!

We would like to thank our contributors, whose efforts make this software what it is. These people have helped by writing code and documentation, and by testing. They have created and maintained this product, its associated libraries and applications, our build tools and our web sites.

#### Contributors

- Ackerley, Nick
- Allgeyer, Sebastien
- Ammon, Charles J.
- Antunes, Emanuel
- Arnarsson, Ólafur St.
- Bank, Markus
- Barsch, Robert
- Behr, Yannik
- Bernardi, Fabrizio
- Bernauer, Felix
- Bes de Berc, Maxime
- Beyreuther, Moritz
- Boltz, Shawn
- Bonaimé, Sébastien
- Carothers, Lloyd
- Chamberlain, Calum
- Chambers, Derrick
- Chen, Zhao
- Clark, Adam
- Danecek, Peter
- Egdorf, Sven
- Engels, Fabian
- Ermert, Laura
- Eulenfeld, Tom

- Fabbri, Tommaso
- Falco, Nicholas
- Fee, Jeremy
- Grellier, Clément
- Grunberg, Marc
- Hammer, Conny
- Heimann, Sebastian
- Heiniger, Lukas
- Hope, Gaute
- Igel, Heiner
- Inza, Adolfo
- Isken, Marius
- Ketchum, David
- Koymans, Mathijs
- Kremers, Simon
- Kress, Victor
- Krieger, Lars
- Krischer, Lion
- Kula, Damian
- Käufl, Paul
- Köhler, Andreas
- Lecocq, Thomas
- Leeman, John
- Legovini, Paride

- Lesage, Philippe
- Li, Yulin
- Lomax, Anthony
- Lopes, Rui L.
- MacCarthy, Jonathan
- Maggi, Alessia
- Martin, Henri
- Medlin, Andrew
- Megies, Tobias
- Meschede, Matthias
- Michelini, Alberto
- Miller, Nathaniel C.
- Morgenstern, Bernhard
- Nof, Ran Novitsky
- Panning, Mark P.
- Parker, Tom
- Pestourie, Romain
- Rapagnani, Giovanni
- Reyes, Celso
- Ringler, Adam
- Rothenhäusler, Nicolas
- Russo, Emiliano
- Sales de Andrade, Elliott

- Satriano, Claudio
- Saul, Joachim
- Scheingraber, Chris
- Schneider, Simon
- Sippl, Christian
- Snoke, Arthur
- Stange, Stefan
- Stähler, Simon C.
- Sullivan, Benjamin
- Tian, Dongdong
- Trabant, Chad
- Trani, Luca
- Uieda, Leonardo
- Walker, Andrew
- Walther, Marcus
- Wassermann, Joachim
- Williams, Mark C.
- Winkelman, Andrew
- Zaccarelli, Riccardo
- Zad, Seyed Kasra Hosseini
- Zhu, Lijun
- van Driel, Martin
- van Wijk, Kasper

#### Funds

ObsPy was partially funded by the

- German Science Foundation (DFG) via grant DFG IG 16/9-1
- German Ministry for Education and Research (BMBF), GEOTECHNOLOGIEN grant 03G0646H.
- NERA project (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation) under the European Community's Seventh Framework Programme (FP7/2007-2013) grant agreement n° 262330
- Leibniz Institute for Applied Geophysics (LIAG)
- VERCE EU-FP7 project (no. 283543)