AR_picker

Users Mailing List Archive
1

Dear obspy-users,

I would like to know a bit more about the theory the AR picker is based on
(obspy.signal.trigger.ar_pick).
Is there any paper related to this picker or any further explaination
by the developers?
I found the documentation pages
(https://docs.obspy.org/_modules/obspy/signal/trigger.html#ar_pick
and
https://docs.obspy.org/packages/autogen/obspy.signal.trigger.ar_pick.html#obspy.signal.trigger.ar_pick)
but I couldn"t find background information.
(For the other picker pk_baer Baer 1987 is cited, something like that would be
great.)

Best regards
Gesa Petersen

2

Hi,

From scholar &

Autoregressive (AR) methods (Sleeman and van Eck 1999; Leonard 2000) are used to determine a pick time after a phase onset has already been detected. AR methods work on the principle that a window of the time-series containing signal from a seismic event has different statistical properties than a window containing noise. Using one or more models for the form of the signal, these methods analyse different subwindows of the time-series to find an optimal point that separates a subwindow with statistical properties of noise from one of noise plus signal. This optimal point determines the pick time.

Thomas

3

Dear Gesa,

thanks for pointing out that the reference is missing! The implemented
picker is based on a (grey lit) paper by Takashi Akazawa which is
published with the title: A technique for automatic detection of onset
time of P- and S-Phases in strong motion records, "13th World Conference
of Earthquake Engineering, Vancouver, B.C., Canada, August 1-6, 2004,
paper no. 786. If you do not find it - let me know.

Best Joachim

4

This citation and some more information is also being added to the
official documentation: https://github.com/obspy/obspy/pull/1559

Cheers!

Lion