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Add private _FocalMechanismConvention class and refactor Figure.meca
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‎pygmt/src/_common.py

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Common functions used in multiple PyGMT functions/methods.
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"""
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from collections.abc import Sequence
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from pathlib import Path
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from typing import Any
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from typing import Any, ClassVar, Literal
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from pygmt.exceptions import GMTInvalidInput
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from pygmt.src.which import which
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@@ -39,3 +41,210 @@ def _data_geometry_is_point(data: Any, kind: str) -> bool:
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except FileNotFoundError:
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pass
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return False
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class _FocalMechanismConvention:
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"""
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Class to handle focal mechanism convention, code, and associated parameters.
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Parameters
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----------
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convention
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The focal mechanism convention. Valid values are:
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- ``"aki"``: Aki and Richards convention.
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- ``"gcmt"``: Global CMT (Centroid Moment Tensor) convention.
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- ``"partial"``: Partial focal mechanism convention.
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- ``"mt"``: Moment Tensor convention.
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- ``"principal_axis"``: Principal axis convention.
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component
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The component of the seismic moment tensor to plot. Valid values are:
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- ``"full"``: the full tensor seismic moment tensor
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- ``"dc"``: the closest double coupe defined from the moment tensor (zero trace
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and zero determinant)
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- ``"deviatoric"``: deviatoric part of the moment tensor (zero trace)
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Only valid for conventions ``"mt"`` and ``"principal_axis"``.
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Attributes
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----------
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convention
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The focal mechanism convention.
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params
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List of parameters associated with the focal mechanism convention.
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code
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The single-letter code that can be used in meca/coupe's -S option.
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Examples
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--------
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>>> from pygmt.src._common import _FocalMechanismConvention
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>>> conv = _FocalMechanismConvention("aki")
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>>> conv.convention, conv.code
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('aki', 'a')
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>>> conv.params
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['strike', 'dip', 'rake', 'magnitude']
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>>> conv = _FocalMechanismConvention("gcmt")
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>>> conv.convention, conv.code
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('gcmt', 'c')
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>>> conv.params
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['strike1', 'dip1', 'rake1', 'strike2', 'dip2', 'rake2', 'mantissa', 'exponent']
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>>> conv = _FocalMechanismConvention("partial")
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>>> conv.convention, conv.code
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('partial', 'p')
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>>> conv.params
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['strike1', 'dip1', 'strike2', 'fault_type', 'magnitude']
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>>> conv = _FocalMechanismConvention("mt", component="dc")
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>>> conv.convention, conv.code
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('mt', 'd')
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>>> conv.params
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['mrr', 'mtt', 'mff', 'mrt', 'mrf', 'mtf', 'exponent']
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>>> conv = _FocalMechanismConvention("principal_axis", component="deviatoric")
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>>> conv.convention, conv.code
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('principal_axis', 't')
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>>> conv = _FocalMechanismConvention("a")
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>>> conv.convention, conv.code
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('aki', 'a')
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>>> conv = _FocalMechanismConvention.from_params(
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... ["strike", "dip", "rake", "magnitude"]
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... )
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>>> conv.convention, conv.code
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('aki', 'a')
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>>> conv = _FocalMechanismConvention(convention="invalid")
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Traceback (most recent call last):
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...
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pygmt.exceptions.GMTInvalidInput: Invalid focal mechanism convention 'invalid'.
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>>> conv = _FocalMechanismConvention("mt", component="invalid")
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Traceback (most recent call last):
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...
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pygmt.exceptions.GMTInvalidInput: Invalid component 'invalid' for ... 'mt'.
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>>> _FocalMechanismConvention.from_params(["strike", "dip", "rake"])
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Traceback (most recent call last):
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...
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pygmt.exceptions.GMTInvalidInput: Fail to determine ...
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"""
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# Mapping of focal mechanism conventions to their single-letter codes.
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_conventions: ClassVar = {
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"aki": "a",
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"gcmt": "c",
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"partial": "p",
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"mt": {"full": "m", "deviatoric": "z", "dc": "d"},
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"principal_axis": {"full": "x", "deviatoric": "t", "dc": "y"},
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}
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# Mapping of single-letter codes to focal mechanism convention names
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_codes: ClassVar = {
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"a": "aki",
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"c": "gcmt",
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"p": "partial",
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"m": "mt",
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"z": "mt",
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"d": "mt",
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"x": "principal_axis",
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"t": "principal_axis",
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"y": "principal_axis",
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}
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# Mapping of focal mechanism conventions to their parameters.
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_params: ClassVar = {
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"aki": ["strike", "dip", "rake", "magnitude"],
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"gcmt": [
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"strike1",
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"dip1",
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"rake1",
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"strike2",
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"dip2",
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"rake2",
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"mantissa",
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"exponent",
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],
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"partial": ["strike1", "dip1", "strike2", "fault_type", "magnitude"],
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"mt": ["mrr", "mtt", "mff", "mrt", "mrf", "mtf", "exponent"],
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"principal_axis": [
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"t_value",
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"t_azimuth",
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"t_plunge",
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"n_value",
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"n_azimuth",
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"n_plunge",
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"p_value",
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"p_azimuth",
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"p_plunge",
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"exponent",
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],
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}
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def __init__(
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self,
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convention: Literal["aki", "gcmt", "partial", "mt", "principal_axis"],
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component: Literal["full", "deviatoric", "dc"] = "full",
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):
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"""
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Initialize the FocalMechanismConvention object.
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"""
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if convention in self._conventions:
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# Convention is given via 'convention' and 'component' parameters.
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if component not in {"full", "deviatoric", "dc"}:
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msg = (
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f"Invalid component '{component}' for focal mechanism convention "
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f"'{convention}'."
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)
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raise GMTInvalidInput(msg)
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self.convention = convention
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self.code = self._conventions[convention]
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if isinstance(self.code, dict):
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self.code = self.code[component]
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elif convention in self._codes:
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# Convention is given as a single-letter code.
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self.code = convention
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self.convention = self._codes[convention]
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else:
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msg = f"Invalid focal mechanism convention '{convention}'."
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raise GMTInvalidInput(msg)
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self.params = self._params[self.convention]
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@staticmethod
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def from_params(
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params: Sequence[str], component: Literal["full", "deviatoric", "dc"] = "full"
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) -> "_FocalMechanismConvention":
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"""
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Create a FocalMechanismConvention object from a sequence of parameters.
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The method checks if the given parameters are a superset of a known focal
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mechanism convention to determine the convention. If the parameters are not
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sufficient to determine the convention, an exception is raised.
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Parameters
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----------
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params
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Sequence of parameters to determine the focal mechanism convention. The
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order of the parameters does not matter.
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Returns
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-------
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_FocalMechanismConvention
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The FocalMechanismConvention object.
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Raises
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------
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GMTInvalidInput
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If the focal mechanism convention cannot be determined from the given
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parameters
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"""
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for convention, param_list in _FocalMechanismConvention._params.items():
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if set(param_list).issubset(set(params)):
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return _FocalMechanismConvention(convention, component=component)
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msg = "Fail to determine focal mechanism convention from the data column names."
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raise GMTInvalidInput(msg)

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