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FilterPicker - a general purpose, broad-band, phase detector and picker

FilterPicker (Lomax et al., 2011) is a general purpose, broad-band, phase detector and picker which is applicable to real-time seismic monitoring and earthquake early-warning. FP uses an efficient algorithm which operates stably on continuous, real-time, broadband signals, avoids excessive picking during large events, and produces onset timing, realistic timing uncertainty, onset polarity and amplitude information. In practice, it operates on a pre-defined number of frequency bands by generating a set of band-passed time-series with different center frequencies. Characteristic functions are determined for each frequency band and a pick is declared if and when, within a window of predefined time width, the integral of the maximum of the characteristic functions exceeds a pre-defined threshold.

Lomax, A., C. Satriano and M. Vassallo (2012), Automatic picker developments and optimization: FilterPicker - a robust, broadband picker for real-time seismic monitoring and earthquake early-warning, Seism. Res. Lett. , 83, 531-540, doi: 10.1785/gssrl.83.3.531. (PDF, Erratum).

Vassallo, M., C. Satriano and A. Lomax, (2012), Automatic picker developments and optimization: A strategy for improving the performances of automatic phase pickers, Seism. Res. Lett. , 83, 541-554, doi: 10.1785/gssrl.83.3.541. (PDF).

Try the FilterPicker

You can try online the FilterPicker in SeisGram2K: Click here to try the SeisGram2K Seismogram Viewer  

Download and install the FilterPicker:

C source: download.

Java source: Use and dependent classes in the source distributed at:  

Earthworm module: Get the code out of earthworm SVN repository, in the directory earthworm/src/seismic_processing/pick_FP. Instructions are here:

Matlab implementation: Developed and maintained by Yavor Kamer: MATLAB Central.

Python implementation: Developed and maintained by Matteo Bagagli (ETH Zürich): Compatible with ObsPy (, an example is provided.

Support FilterPicker development

The development of FilterPicker has been funded by Analisi e Monitoraggio del Rischio Ambientale: Analysis and Monitoring of Environmental Risk (AMRA scarl) through the Seismic Early Warning for Europe (SAFER) project, the EU’s Sixth Framework Programme, and through the ReLUIS-DPC project.

The further development and maintenance of FilterPicker is funded by software and research contracts with Anthony Lomax.  If you have a specific development or research request concerning FilterPicker or other open source software, please contact Anthony Lomax or visit the ALomax Scientific web site.  Thanks!


Any Questions? Comments? Please e-mail to Anthony Lomax.

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The FilterPicker software was conceived and developed by:
Anthony Lomax

ALomax Scientific -