5.12.1.3. eqcorrscan.utils.pre_processing.shortproc

eqcorrscan.utils.pre_processing.shortproc(st, lowcut, highcut, filt_order, samp_rate, debug=0, parallel=False, num_cores=False, starttime=None, endtime=None, seisan_chan_names=False, fill_gaps=True)[source]

Basic function to bandpass and downsample.

Works in place on data. This is employed to ensure all parts of the data are processed in the same way.

Parameters:
  • st (obspy.core.stream.Stream) – Stream to process
  • lowcut (float) – Low cut for bandpass in Hz
  • highcut (float) – High cut for bandpass in Hz
  • filt_order (int) – Number of corners for bandpass filter
  • samp_rate (float) – Sampling rate desired in Hz
  • debug (int) – Debug flag from 0-5, higher numbers = more output
  • parallel (bool) – Set to True to process traces in parallel, for small numbers of traces this is often slower than serial processing, defaults to False
  • num_cores (int) – Control the number of cores for parallel processing, if set to False then this will use all the cores.
  • starttime (obspy.core.utcdatetime.UTCDateTime) – Desired data start time, will trim to this before processing
  • endtime (obspy.core.utcdatetime.UTCDateTime) – Desired data end time, will trim to this before processing
  • seisan_chan_names (bool) – Whether channels are named like seisan channels (which are two letters rather than SEED convention of three) - defaults to True.
  • fill_gaps (bool) – Whether to pad any gaps found with zeros or not.
Returns:

Processed stream

Return type:

obspy.core.stream.Stream

Note

Will convert channel names to two characters long.

Warning

If you intend to use this for processing templates you should consider how resampling will impact your cross-correlations. Minor differences in resampling between day-long files (which you are likely to use for continuous detection) and shorter files will reduce your cross-correlations!

Example, bandpass

>>> from obspy import read
>>> from eqcorrscan.utils.pre_processing import shortproc
>>> st = read('eqcorrscan/tests/test_data/WAV/TEST_/' +
...           '2013-09-01-0410-35.DFDPC_024_00')
>>> st = shortproc(st=st, lowcut=2, highcut=9, filt_order=3, samp_rate=20,
...                debug=0, parallel=True, num_cores=2)
>>> print(st[0])
AF.LABE..SHZ | 2013-09-01T04:10:35.700000Z - 2013-09-01T04:12:05.650000Z | 20.0 Hz, 1800 samples

Example, low-pass

>>> from obspy import read
>>> from eqcorrscan.utils.pre_processing import shortproc
>>> st = read('eqcorrscan/tests/test_data/WAV/TEST_/' +
...           '2013-09-01-0410-35.DFDPC_024_00')
>>> st = shortproc(st=st, lowcut=None, highcut=9, filt_order=3,
...                samp_rate=20, debug=0)
>>> print(st[0])
AF.LABE..SHZ | 2013-09-01T04:10:35.700000Z - 2013-09-01T04:12:05.650000Z | 20.0 Hz, 1800 samples

Example, high-pass

>>> from obspy import read
>>> from eqcorrscan.utils.pre_processing import shortproc
>>> st = read('eqcorrscan/tests/test_data/WAV/TEST_/' +
...           '2013-09-01-0410-35.DFDPC_024_00')
>>> st = shortproc(st=st, lowcut=2, highcut=None, filt_order=3,
...                samp_rate=20, debug=0)
>>> print(st[0])
AF.LABE..SHZ | 2013-09-01T04:10:35.700000Z - 2013-09-01T04:12:05.650000Z | 20.0 Hz, 1800 samples