# obspy.core.event.origin.Arrival

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

  Bases: `obspy.core.event.base.__Arrival`

  Successful association of a pick with an origin qualifies this pick as an arrival. An arrival thus connects a pick with an origin and provides additional attributes that describe this relationship. Usually qualification of a pick as an arrival for a given origin is a hypothesis, which is based on assumptions about the type of arrival (phase) as well as observed and (on the basis of an earth model) computed arrival times, or the residual, respectively. Additional pick attributes like the horizontal slowness and backazimuth of the observed wave—especially if derived from array data—may further constrain the nature of the arrival.

  Parameters: | resource_id (`ResourceIdentifier`) Resource identifier of Arrival. 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. pick_id (`ResourceIdentifier`) Refers to the resource_id of a Pick. phase (str) Phase identification. For possible values, please refer to the description of the Phase object. time_correction (float, optional) Time correction value. Usually, a value characteristic for the station at which the pick was detected, sometimes also characteristic for the phase type or the slowness. Unit: s azimuth (float, optional) Azimuth of station as seen from the epicenter. Unit: deg distance (float, optional) Epicentral distance. Unit: deg takeoff_angle (float, optional) Angle of emerging ray at the source, measured against the downward normal direction. Unit: deg takeoff_angle_errors (`QuantityError`) AttribDict containing error quantities. time_residual (float, optional) Residual between observed and expected arrival time assuming proper phase identification and given the earth_model_ID of the Origin, taking into account the time_correction. Unit: s horizontal_slowness_residual (float, optional) Residual of horizontal slowness and the expected slowness given the current origin (refers to attribute horizontal_slowness of class Pick). backazimuth_residual (float, optional) Residual of backazimuth and the backazimuth computed for the current origin (refers to attribute backazimuth of class Pick). time_weight (float, optional) Weight of the arrival time for computation of the associated Origin. Note that the sum of all weights is not required to be unity. horizontal_slowness_weight (float, optional) Weight of the horizontal slowness for computation of the associated Origin. Note that the sum of all weights is not required to be unity. backazimuth_weight (float, optional) Weight of the backazimuth for computation of the associated Origin. Note that the sum of all weights is not required to be unity. earth_model_id (`ResourceIdentifier`, optional) Earth model which is used for the association of Arrival to Pick and computation of the residuals. comments (list of `Comment`, optional) Additional comments. creation_info (`CreationInfo`, optional) CreationInfo for the Arrival object.

  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)