Calculate the correction for the differential pick time determined by cross correlation of the waveforms in narrow windows around the pick times. For details on the fitting procedure refer to [Deichmann1992].
The parameters depend on the epicentral distance and magnitude range. For small local earthquakes (Ml ~0-2, distance ~3-10 km) with consistent manual picks the following can be tried:
t_before=0.05, t_after=0.2, cc_maxlag=0.10,
filter="bandpass", filter_options={'filter_low': 1, 'filter_high': 20}
The appropriate parameter sets can and should be determined/verified visually using the option show=True on a representative set of picks.
To get the corrected differential pick time calculate: ((pick2 + pick2_corr) - pick1). To get a corrected differential travel time using origin times for both events calculate: ((pick2 + pick2_corr - ot2) - (pick1 - ot1))
Parameters: |
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Return type: | (float, float) |
Returns: | Correction time pick2_corr for pick2 pick time as a float and corresponding correlation coefficient. |