5.2.10.4. eqcorrscan.utils.plotting.freq_mag

eqcorrscan.utils.plotting.freq_mag(magnitudes, completeness, max_mag, binsize=0.2, **kwargs)[source]

Plot a frequency-magnitude histogram and cumulative density plot.

Currently this will compute a b-value, for a given completeness. B-value is computed by linear fitting to section of curve between completeness and max_mag.

Parameters:
  • magnitudes (list) – list of float of magnitudes

  • completeness (float) – Level to compute the b-value above

  • max_mag (float) – Maximum magnitude to try and fit a b-value to

  • binsize (float) – Width of histogram bins, defaults to 0.2

  • title (str) – Title of figure

  • show (bool) – Whether to show the figure or not (defaults to True)

  • save (bool) – Whether to save the figure or not (defaults to False)

  • savefile (str) – Filename to save figure to, if save==True (defaults to “EQcorrscan_figure.png”)

  • return_figure (bool) – Whether to return the figure or not (defaults to True), if False then the figure will be cleared and closed.

  • size (tuple of float) – Figure size as (width, height) in inches. Defaults to (10.5, 7.5)

Returns:

matplotlib.figure.Figure

Note

See eqcorrscan.utils.mag_calc.calc_b_value() for a least-squares method of estimating completeness and b-value. For estimating maximum curvature see eqcorrscan.utils.mag_calc.calc_max_curv().

Example

>>> from obspy.clients.fdsn import Client
>>> from obspy import UTCDateTime
>>> from eqcorrscan.utils.plotting import freq_mag
>>> client = Client('IRIS')
>>> t1 = UTCDateTime('2012-03-26T00:00:00')
>>> t2 = t1 + (3 * 86400)
>>> catalog = client.get_events(starttime=t1, endtime=t2, minmagnitude=3)
>>> magnitudes = [event.preferred_magnitude().mag for event in catalog]
>>> freq_mag(magnitudes, completeness=4, max_mag=7) 

(Source code)