phase picker
command: PICK <trace> [<start-time> <end-time>] [<onset-var>]
Implementation of M. Baer's and U. Kradolfer's phase picker (An Automatic Phase Picker for Local and Teleseismic Events, BSSA, Vol. 77, No. 4, pp. 1437-1445, Aug. 87). Within the specified time window (relative times) on trace <trace> the onset time of the first phase found is marked and returned (absolute time) in variable <onset-var> if specified. If no time window is given the whole trace is used. The parameters of the picker can be set via qualifiers /DURATION, /BREAKLTH and /THRESHOLD.
parameters
- <trace> parameter type: trace
Selected trace.
- <start-time>, <end-time> parameter type: real
Start and end time of window in which a phase is searched. If not specified the whole trace is used.
- <onset-var> parameter type: symbol address
Variable where to store the onset time found. Is empty if no onset can be detected.
qualifiers
- /duration=<duration>
Selects the minimum duration (in sec) the signal on the characteristic function must be over the threshold. Default is 1 sec.
- /breaklth=<breaklth>
Selects the maximum allowed break length within <duration> where the signal is allowed to fall below the threshold. Default is 0 sec (no interruptions of the signal within <duration> allowed).
- /threshold=<threshold>
Detection threshold. Default is 10.
- /keep
Keeps envelope (in power of 4) and characteristic function as additional traces on screen.
example
- pick 1 80.0 110.0 &g1 /duration=0.3
- searches phase on trace 1 within time window from 80 to 110 sec and puts result to variable g1. Uses duration of 0.3 sec.
