core.match_filter.detection

Functions for network matched-filter detection of seismic data.

Designed to cross-correlate templates generated by template_gen function with data and output the detections.

copyright

EQcorrscan developers.

license

GNU Lesser General Public License, Version 3 (https://www.gnu.org/copyleft/lesser.html)


class eqcorrscan.core.match_filter.detection.Detection(template_name, detect_time, no_chans, detect_val, threshold, typeofdet, threshold_type, threshold_input, chans=None, event=None, id=None)[source]

Single detection from detection routines in eqcorrscan. Information required for a full detection based on cross-channel correlation sums.

Parameters
  • template_name (str) – The name of the template for which this detection was made.

  • detect_time (obspy.core.utcdatetime.UTCDateTime) – Time of detection as an obspy UTCDateTime object

  • no_chans (int) – The number of channels for which the cross-channel correlation sum was calculated over.

  • detect_val (float) – The raw value of the cross-channel correlation sum for this detection.

  • threshold (float) – The value of the threshold used for this detection, will be the raw threshold value related to the cccsum.

  • typeofdet (str) – Type of detection, STA, corr, bright

  • threshold_type (str) – Type of threshold used for detection

  • threshold_input (float) – Threshold set for detection, relates to threshold according to the threshold_type.

  • chans (list) – List of stations for the detection

  • event (obspy.core.event.event.Event) – Obspy Event object for this detection, note that this is lost when writing to a Detection objects to csv files using eqcorrscan.core.match_filter.Detection.write()

  • id (str) – Identification for detection (should be unique).

Methods

copy()

Returns a copy of the detection.

extract_stream(stream, length, prepick)

Extract a cut stream of a given length around the detection.

write(fname[, append])

Write detection to csv formatted file.

__init__(template_name, detect_time, no_chans, detect_val, threshold, typeofdet, threshold_type, threshold_input, chans=None, event=None, id=None)[source]

Main class of Detection.

copy()[source]

Returns a copy of the detection.

Returns

Copy of detection

extract_stream(stream, length, prepick)[source]

Extract a cut stream of a given length around the detection.

Parameters
  • stream (obspy.core.stream.Stream) – Stream of data to cut from

  • length (float) – Length of data to extract in seconds.

  • prepick (float) – Length before the expected pick on each channel to start the cut stream in seconds.

Return type

obspy.core.stream.Stream

write(fname, append=True)[source]

Write detection to csv formatted file.

Will append if append==True and file exists

Parameters
  • fname (str) – Full path to file to open and write to.

  • append (bool) – Set to true to append to an existing file, if True and file doesn’t exist, will create new file and warn. If False will overwrite old files.

Functions

eqcorrscan.core.match_filter.detection.read_detections(fname, encoding='UTF8')[source]

Read detections from a file to a list of Detection objects.

Parameters
  • fname (str) – File to read from, must be a file written to by Detection.write.

  • encoding (str) – Encoding used for detection file.

Returns

list of eqcorrscan.core.match_filter.Detection

Return type

list

Note

eqcorrscan.core.match_filter.detection.Detection’s returned do not contain Detection.event

eqcorrscan.core.match_filter.detection.write_catalog(detections, fname, format='QUAKEML')[source]

Write events contained within detections to a catalog file.

Parameters
  • detections (list) – list of eqcorrscan.core.match_filter.Detection

  • fname (str) – Name of the file to write to

  • format (str) – File format to use, see obspy.core.event.Catalog.write for supported formats.

eqcorrscan.core.match_filter.detection.get_catalog(detections)[source]

Generate an obspy.core.event.Catalog from list of Detection’s.

Parameters

detections (list) – list of eqcorrscan.core.match_filter.Detection

Returns

Catalog of detected events.

Return type

obspy.core.event.Catalog

Warning

Will only work if the detections have an event associated with them. This will not be the case if detections have been written to csv format using eqcorrscan.core.match_filter.Detection.write() and read back in.