3.6.1.2. quakemigrate.signal.pickers

The quakemigrate.pickers module handles the picking of seismic phases. The default method makes the phase picks by fitting a 1-D Gaussian to the Onset function.

Feel free to contribute more phase picking methods!

copyright: 2020–2023, QuakeMigrate developers.
license: GNU General Public License, Version 3 (https://www.gnu.org/licenses/gpl-3.0.html)

3.6.1.2.1. quakemigrate.signal.pickers.base

A simple abstract base class with method stubs enabling simple modification of QuakeMigrate to use custom phase picking methods that remain compatible with the core of the package.

copyright: 2020–2023, QuakeMigrate developers.
license: GNU General Public License, Version 3 (https://www.gnu.org/licenses/gpl-3.0.html)

class quakemigrate.signal.pickers.base.PhasePicker(**kwargs)[source]

Bases: ABC

Abstract base class providing a simple way of modifying the default picking function in QuakeMigrate.

plot_picks

Toggle plotting of phase picks.

Type: bool

pick_phases()[source]: Abstract method stub providing interface with QuakeMigrate scan.

write(event_uid, phase_picks, output)[source]: Outputs phase picks to file.

plot()[source]: Method stub for phase pick plotting.

abstract pick_phases()[source]: Method stub for phase picking.

plot()[source]: Method stub for phase pick plotting.

write(run, event_uid, phase_picks)[source]

Write phase picks to a new .picks file.

Parameters

event_uid (str) – Unique identifier for the event.
phase_picks (pandas DataFrame object) –

Phase pick times with columns: [“Name”, “Phase”,
”ModelledTime”, “PickTime”, “PickError”, “SNR”]

Each row contains the phase pick from one station/phase.
output (QuakeMigrate input/output control object) – Contains useful methods controlling output for the scan.

3.6.1.2.2. quakemigrate.signal.pickers.gaussian

The default seismic phase picking class - fits a 1-D Gaussian to the calculated onset functions.

copyright: 2020–2023, QuakeMigrate developers.
license: GNU General Public License, Version 3 (https://www.gnu.org/licenses/gpl-3.0.html)

class quakemigrate.signal.pickers.gaussian.GaussianPicker(onset=None, **kwargs)[source]

Bases: PhasePicker

This class details the default method of making phase picks shipped with QuakeMigrate, namely fitting a 1-D Gaussian function to the onset function for each station and phase.

phase_picks

“GAU_P”array-like: Numpy array stack of Gaussian pick info (each as a dict) for P phase
“GAU_S”array-like: Numpy array stack of Gaussian pick info (each as a dict) for S phase

Type: dict

threshold_method

Which method to use to calculate the pick threshold; a percentile of the data outside the pick windows (e.g. 0.99 = 99th percentile) or a multiple of the Median Absolute Deviation of the signal outside the pick windows. Default uses the MAD method.

Type: {“MAD”, “percentile”}

percentile_pick_threshold

Picks will only be made if the onset function exceeds this percentile of the noise level (amplitude of onset function outside pick windows). (Default: 1.0)

Type: float, optional

mad_pick_threshold

Picks will only be made if the onset function exceeds its median value plus this multiple of the MAD (calculated from the onset data outside the pick windows). (Default: 8)

Type: float, optional

plot_picks

Toggle plotting of phase picks.

Type: bool

pick_phases(event, lut, run)[source]: Picks phase arrival times for located events by fitting a 1-D Gaussian function to the P and/or S onset functions

DEFAULT_GAUSSIAN_FIT = {'PickValue': -1, 'popt': 0, 'xdata': 0, 'xdata_dt': 0}

property fraction_tt: Handler for deprecated attribute ‘fraction_tt’

pick_phases(event, lut, run)[source]

Picks phase arrival times for located events.

Parameters

event (Event object) – Light class encapsulating waveforms, coalescence information and location information for a given event.
lut (LUT object) – Contains the traveltime lookup tables for seismic phases, computed for some pre-defined velocity model.
run (Run object) – Light class encapsulating i/o path information for a given run.

Returns

event (Event object) – Event object provided to pick_phases(), but now with phase picks!
picks (pandas.DataFrame) – DataFrame that contains the measured picks with columns: [“Name”, “Phase”, “ModelledTime”, “PickTime”, “PickError”, “SNR”] Each row contains the phase pick from one station/phase.

property pick_threshold: Handler for deprecated attribute ‘pick_threshold’

plot(event, station, onset_data, picks_df, traveltimes, run)[source]

Plot figure showing the filtered traces for each data component and the onset functions calculated from them (P and/or S) for each station. The search window to make a phase pick is displayed, along with the dynamic pick threshold, the phase pick time and its uncertainty (if made) and the Gaussian fit to the onset function.

Parameters

event (Event object) – Light class to encapsulate information about an event, including origin time, location and waveform data.
station (str) – Station name.
onset_data (OnsetData object) – Light class encapsulating data generated during onset calculation.
picks_df (pandas.DataFrame object) – DataFrame that contains the measured picks with columns: [“Name”, “Phase”, “ModelledTime”, “PickTime”, “PickError”, “SNR”] Each row contains the phase pick from one station/phase.
traveltimes (list of float) – Modelled traveltimes from the event hypocentre to the station for each phase to be plotted.
run (Run object) – Light class encapsulating i/o path information for a given run.