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By T. Utheim, University of Bergen.
The AUTOPHASE program is part of the RTQUAKE real-time earthquake detection [Utheim et al., 2014]. The AUTOPHASE (hereafter AP) is a stand-alone phase-picker routine that is used for automatic phase-picking in RTQUAKE and can also be used as an option in SEISAN from the EEV program. The routine is based on the FilterPicker algorithm [Lomax et al., 2012], but with several modifications and additions. However, the original picking algorithm is unchanged.
The FilterPicker (hereafter FP) implementation in both RTQUAKE and SEISAN checks each component of a waveform for possible phase-picks. All channels in the waveform file are checked and there is no possibility to unselect channels. Each component may have several suggested phases given by the time of occurrence. Each component may also have a suggested first movement indicated for each pick. There can thus be many picks for each channel.
The following rules apply for selecting P and S phases among the suggested picks:
For one station there will only be one P and one S-phase selected.
P is only accepted on vertical components.
S is only accepted on vertical components if the station does not have horizontal components so S is in general only accepted on horizontal components. If several picks are found on a horizontal component, it is assumed that the first is P. The S is then selected on the first of the following picks that has a time-difference greater than a default value MINDIFF (1.5 seconds) set in the program. This is to avoid picking secondary P phases as S phases. This rule is also used if picking S on Z-components.
If S-phases are found on two different horizontal channels, the first arriving one is used.
If only one pick on a horizontal component, no S is selected.
First movement are included in the S-file only for vertical channels.
If the event is defined as distant (D) in the SEISAN S-file, only P phases are picked.
S-phases are given a weight of 3.
Running AUTOPHASE AP is started from within the SEISAN EEV program with the command 'ap'. This command converts all associated waveform files (can be different formats) to one MiniSeed file seed.out, which is then used as input to AUTOPHASE. The S-file and corresponding waveform files are used as input to the AP. All old readings are deleted and replaced by the new readings from AP. All phases are marked with A for automatic. AUTOPHASE can also be operated outside EEV with the command:
Autophase -sfile xxx -wavefile yyy
where xxx is a single event S-file and yyy is one waveform file in MiniSeed format. AP can only work with one S-file.
AUTOPHASE also has other options not used in SEISAN, see RTQUAKE manual:
ftp://ftp.geo.uib.no/pub/seismo/SOFTWARE/RTQUAKE/
Parameters
AUTOPHASE has no parameter file since it seems that the default parameter work will in most cases. Default FilterPicker parameters are set at the top in the source program under the comment:
"Default FilterPicker parameters" and can be changed by the user. See M. Vassallo and Lomax [2012] for documentation. The program must be recompiled.
#define Picker_FW 300.0 Longest period for a set of filtered signals from the differential signal of the raw broadband input trace (300 multiplied by sample rate)
#define Picker_LTW 500.0 Time scale used for accumulating time-averaged statistics of the input raw signal (500 multiplied by sample rate)
#define Picker_TH1 10.0 Trigger threshold used for event declaration. A trigger is declared when the summary CF (characteristic function) exceeds Picker_TH1
#define Picker_TH2 10.0 A pick is declared if and when, within a window of predefined time width, Picker_TUP after trigger time, the integral summary CF (characteristic function) exceeds the value: Picker_TH2 multiplied by Picker_TUP (see below).
#define Picker_TUP 20.0 Time window used for pick validation (20 multiplied by sample rate).
Default time-difference MINDEF is set to:
MINDEF = 1.5
Coda is computed for vertical components only, and only for events marked local (L) or regional (R) in the s-file. Computation of coda can be turned off by changing the SETCODA switch in the source code to zero, and recompiling. Default is SETCODA=1. The coda is computed by comparing a long-term average of the signal before the P phase with long-term averages after the P-phase divided by a factor.
Example: The AUTOPHASE picker is started from EEV with the command: ap
# 13 9 Dec 2015 08:03 54 LM-22.259 -66.832 0.0 N 1.2 2.3WBER 11 ? ap The waveform file is converted to miniseed file: seed.out wavetool -sfile /home/seismo/snew/REA/TST__/2015/12/09-0804-18R.S201512 -format MSEED -wav_out_file seed.out Number of wav-files 1 Number of wav-files present 1 /home/seismo/snew/WAV/TST__/2015/12/2015 MINISEED Total number of channels available: 42 Total duration: 323.599976 Output waveform file name is seed.out Here the autophase routine is started with s-file and seed.out file as input: autophase -sfile /home/seismo/snew/REA/TST__/2015/12/09-0804-18R.S201512 -wavefile seed.out SEISAN_TOP.......................: /home/seismo/snew wfilename: seed.out All picks found are listed below in the format: STATION-NAME DATE TIME TIME-DIFFERENCE TO NEXT PICK ON SAME COMPONENT CX_PB16__00_BHZ 09/12/15 08:05:04.499 (1 pick only) CX_PB11__00_BHZ 09/12/15 08:04:49.150 39.85 (2 picks, time-diff. to 2. pick:39.85 seconds) CX_PB11__00_BHN 09/12/15 08:04:49.349 39.30 CX_PB11__00_BHE 09/12/15 08:04:49.349 39.55 CX_PB08__00_BHZ 09/12/15 08:04:43.769 CX_PB08__00_BHN 09/12/15 08:04:43.819 35.35 CX_PB08__00_BHE 09/12/15 08:04:43.919 35.40 CX_PB01__00_BHZ 09/12/15 08:04:38.269 CX_PB01__00_BHN 09/12/15 08:04:38.569 31.25 CX_PB01__00_BHE 09/12/15 08:04:38.569 31.95 CX_PB07__00_BHZ 09/12/15 08:04:39.019 CX_PB07__00_BHN 09/12/15 08:04:38.969 CX_PB07__00_BHE 09/12/15 08:04:39.069 CX_PB09__00_BHZ 09/12/15 08:04:33.650 CX_PB09__00_BHN 09/12/15 08:04:33.999 CX_PB09__00_BHE 09/12/15 08:04:33.799 CX_PB03__00_BHZ 09/12/15 08:04:37.569 CX_PB03__00_BHN 09/12/15 08:04:37.469 CX_PB03__00_BHE 09/12/15 08:04:37.469 CX_PB04__00_BHZ 09/12/15 08:04:41.369 CX_PB04__00_BHN 09/12/15 08:04:41.669 CX_PB04__00_BHE 09/12/15 08:04:41.619 0.90 CX_PB06__00_BHZ 09/12/15 08:04:36.519 CX_PB06__00_BHN 09/12/15 08:04:36.919 30.15 CX_PB06__00_BHE 09/12/15 08:04:36.769 CX_PB05__00_BHZ 09/12/15 08:04:42.619 CX_PB05__00_BHN 09/12/15 08:04:43.069 CX_PB05__00_BHE 09/12/15 08:04:42.769 CX_PB15__00_BHZ 09/12/15 08:04:37.869 1.20 30.50 (3 picks,and 2 time-differences) CX_PB15__00_BHN 09/12/15 08:04:37.669 31.65 CX_PB15__00_BHE 09/12/15 08:04:38.169 31.30 CX_PB10__00_BHE 09/12/15 08:04:48.500 ----------------------------------------------------------------------- SELECTED PICKS: ----------------------------------------------------------------------- Below the selected picks from the picks above. As seen below, there are picks on both horizontal components on stations PB11,PB08,PB01 and PB15: 0 PB16 BHZ P 09/12/15 08:05:04.499 6 PB11 BHZ P 09/12/15 08:04:49.150 7 PB11 BHN S 09/12/15 08:05:28.649 8 PB11 BHE S 09/12/15 08:05:28.899 9 PB08 BHZ P 09/12/15 08:04:43.769 C 10 PB08 BHN S 09/12/15 08:05:19.169 11 PB08 BHE S 09/12/15 08:05:19.319 12 PB01 BHZ P 09/12/15 08:04:38.269 13 PB01 BHN S 09/12/15 08:05:09.819 14 PB01 BHE S 09/12/15 08:05:10.519 15 PB07 BHZ P 09/12/15 08:04:39.019 18 PB09 BHZ P 09/12/15 08:04:33.650 C 21 PB03 BHZ P 09/12/15 08:04:37.569 24 PB04 BHZ P 09/12/15 08:04:41.369 27 PB06 BHZ P 09/12/15 08:04:36.519 28 PB06 BHN S 09/12/15 08:05:07.069 30 PB05 BHZ P 09/12/15 08:04:42.619 33 PB15 BHZ P 09/12/15 08:04:37.869 34 PB15 BHN S 09/12/15 08:05:09.319 35 PB15 BHE S 09/12/15 08:05:09.469 ---------------------------------------------------------------------------------------- In the next step of selection the first of the 2 S-phases on the horizontal components are selected while the last are deleted: 0 PB16 BHZ P 09/12/15 08:05:04.499 6 PB11 BHZ P 09/12/15 08:04:49.150 7 PB11 BHN S 09/12/15 08:05:28.649 9 PB08 BHZ P 09/12/15 08:04:43.769 C 10 PB08 BHN S 09/12/15 08:05:19.169 12 PB01 BHZ P 09/12/15 08:04:38.269 13 PB01 BHN S 09/12/15 08:05:09.819 15 PB07 BHZ P 09/12/15 08:04:39.019 18 PB09 BHZ P 09/12/15 08:04:33.650 C 21 PB03 BHZ P 09/12/15 08:04:37.569 24 PB04 BHZ P 09/12/15 08:04:41.369 27 PB06 BHZ P 09/12/15 08:04:36.519 28 PB06 BHN S 09/12/15 08:05:07.069 30 PB05 BHZ P 09/12/15 08:04:42.619 33 PB15 BHZ P 09/12/15 08:04:37.869 34 PB15 BHN S 09/12/15 08:05:09.319 ----------------------------------------------------------------------- Create s-file: /home/seismo/snew/REA/TST__/2015/12/09-0804-18R.S201512 ----------------------------------------------------------------------- The autophase routine will also indicate first movement of p-phases when found. This can be seen on station PB08 BZ and PB09 BZ below: 0 2015 12 9 0803 54.7 LM-22.259 -66.832 0.0 BER 11 1.2 2.3WBER 1 1 SPEC AVERAGE MO 12.5 ST 2.2 OM 1.3 f0 6.48 R1.2239 AL 0.00 WI 20.0 MW 2.3 3 2 SPEC SD MO 0.7 ST 1.8 OM 0.7 f0 2.58 R2.8040 AL WI MW 0.5 3 3 GAP=282 2.48 27.2 73.7 98.6 -0.1631E+04 0.5338E+04 -0.1724E+04E 4 SPEC PB09BH Z MO 12.1 ST 1.5 OM 0.9 f0 8.00 R0.1480 AL-0.00 WI 20.0 MW 2.0 3 5 SPEC PB09BH Z T 8 5 5 K 0.020 GD 159 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 6 SPEC PB03BH Z MO 12.3 ST 2.6 OM 1.1 f0 8.00 R0.1480 AL-0.00 WI 20.0 MW 2.1 3 7 SPEC PB03BH Z T 8 519 K 0.020 GD 173 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 8 SPEC PB01BH Z MO 12.4 ST 3.4 OM 1.2 f0 8.00 R0.1480 AL-0.00 WI 20.0 MW 2.2 3 9 SPEC PB01BH Z T 8 5 8 K 0.020 GD 174 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 10 SPEC PB07BH Z MO 12.2 ST 1.1 OM 1.0 f0 6.36 R0.1862 AL-0.00 WI 20.0 MW 2.1 3 11 SPEC PB07BH Z T 8 524 K 0.020 GD 179 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 12 SPEC PB08BH Z MO 14.4 ST0.002 OM 3.2 f00.137 R8.6423 AL-0.00 WI 20.0 MW 3.6 3 13 SPEC PB08BH Z T 8 517 K 0.020 GD 183 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 14 SPEC PB04BH Z MO 12.2 ST 2.2 OM 1.0 f0 8.00 R0.1480 AL-0.00 WI 20.0 MW 2.1 3 15 SPEC PB04BH Z T 8 530 K 0.020 GD 184 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 16 SPEC PB05BH Z MO 11.9 ST0.335 OM 0.7 f0 5.32 R0.2226 AL-0.00 WI 20.0 MW 1.9 3 17 SPEC PB05BH Z T 8 534 K 0.020 GD 187 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 18 SPEC PB11BH Z MO 12.7 ST 6.1 OM 1.4 f0 8.00 R0.1480 AL-0.00 WI 20.0 MW 2.4 3 19 SPEC PB11BH Z T 8 527 K 0.020 GD 200 VS 3.20 DE 2.60 Q0400.0 QA 0.70 Q1 1.00 3 20 2015-12-09-0803-18.TST___054_00_01 6 21 ACTION:NEW 15-12-09 08:04 OP:SEIS STATUS: ID:20151209080418 I 22 STAT SP IPHASW D HRMM SECON CODA AMPLIT PERI AZIMU VELO AIN AR TRES W DIS CAZ7 23 PB16 BZ IP A 8 5 4.49 120 24 PB11 BZ IP A 8 4 49.15 132 25 PB08 BZ IP AC 8 4 43.76 105 26 PB01 BZ IP A 8 4 38.26 125 27 PB07 BZ IP A 8 4 39. 1 122 28 PB09 BZ IP AC 8 4 33.65 121 29 PB03 BZ IP A 8 4 37.56 113 30 PB04 BZ IP A 8 4 41.36 89 31 PB06 BZ IP A 8 4 36.51 86 32 PB05 BZ IP A 8 4 42.61 87 33 PB15 BZ IP A 8 4 37.86 94 34 PB11 BN IS 3A 8 5 28.64 35 PB08 BN IS 3A 8 5 19.16 36 PB01 BN IS 3A 8 5 9.81 37 PB06 BN IS 3A 8 5 7. 6 38 PB15 BN IS 3A 8 5 9.31 # 13 9 Dec 2015 08:03 54 LM-22.259 -66.832 0.0 N 1.2 2.3WBER 11 ?
Peter Voss : Tue Jun 8 13:38:42 UTC 2021
![\begin{figure}\centerline{\includegraphics[width=0.9\linewidth]{fig/autophase}}\end{figure}](img124.png)