Seiscomp3 Autopicker using the Baer / Kradolfer Picking Algorithm

Introduction

Bkpicker is an implementation of the Baer/Kradolfer picker adapted to Seiscomp3.

It was created by converting Manfred Baers picker_ppick.f from Fortran to C++ and inserting it as a replacement for the picker algorithm into a copy of gfzpicker.cpp from Gempa which was renamed to bkpicker.cpp.

Bkpicker is included in scautopick and can be activated in the corresponding configuration file.

Configuration

Edit ~/.seiscomp3/scautopick.cfg, add the following line:

  picker=BK  # can be GFZ, ARAIC or BK

You can configure some parameters for the picker algorithm and the filter:

  # Signal time interval to be postprocessed by the postpicker.
  # Begin and End are in seconds relative to the trigger
  picker.BK.signalBegin=-23
  picker.BK.signalEnd=60
  # Filter configuration
  picker.BK.filterType = BP # BP (Bandpass) is currently the only option
  picker.BK.filterPoles = 2 # number of poles
  picker.BK.f1 = 5          # lower cutoff freq. in Hz
  picker.BK.f2 = 20         # upper cutoff freq. in Hz
  # Baer / Kradolfer picker algorithm parameters
  picker.BK.thrshl1 = 15 # threshold to trigger for pick (c.f. paper), default 10 
  picker.BK.thrshl2 = 20 # threshold for updating sigma  (c.f. paper), default 20

Usage Example For Testing The Picker

  scrttv --buffer-size 300000000 --record-file example.mseed
  scautopick -u dummy --db-disable -vvvvv --console=1  -I example.mseed

Scrttv will first show the waveform without picks, and then, when scautopick is running, will add the picks to the waveform as they are detected by scautopick.

If you want to change the picker only for a short test without modifying the config file, you can also select the postpick processor on the command line:

  scautopick --picker=BK -u dummy --db-disable -vvvvv --console=1  -I example.mseed

Description of the Baer / Kradolfer Algorithm

For details see the Bulletin of the Seismological Societyety of America, Vol. 77, No. 4, pp. 1437-1445,August1987: "An Automatic Phase Picker For Local And Teleseismic Events" by Manfred Baer and Urs Kradolfer