CarlSubTrig creating extra triggers

[Shawn Boltz]

Hello, I have been trying to use CarlStaTrig/CarlSubTrig to detect events on a small network. Because of the network scale and the size of the events, they are very short duration (3-4 seconds) and it is possible to have multiple events that are within just a few seconds of each other.

I have been trying to tune CarlSubTrig to better handle these events that are close together by shortening the trigger times, but now I'm running into problems with it creating two triggers for one event, with the second trigger being useless. What I want is to capture 1-2 seconds before the trigger on to make sure I get the beginning of the event, the time when the trigger was on, and then 1-2 seconds after the trigger to make sure I capture the coda but hopefully not the next event that occurs.

My CarlSubTrig configuration is as follows, it just has a single subnet for the network:

MyModuleId      MOD_CARLSUBTRIG # Module id for this instance of CarlSubTrig -
Debug           2               # Write out debug messages? (0 = No,
RingNameIn      PICK_RING       # Name of ring from which station triggers
RingNameOut     HYPO_RING       # Name of ring to which triggers will be
HeartBeatInterval       30      # Heartbeat Interval (seconds).

# CarlSubTrig Specific Setup
StationFile  ${CARLTRIG_STA_FILE}    # Name of file containing station information -
Latency         300             # Number of seconds that the Network clock
NetTriggerDur   1               # Number of seconds for the base network
SubnetContrib   1               # Addition contribution to network trigger (15 default)
PreEventTime    3               # Number of seconds added to beginning of
MaxDuration     10              # Maximum duration allowed for network trigger (def 500)
DefStationDur   10              # Default number of seconds for station (default 120)
ListSubnets     1               # Flag to list untriggered stations
AllSubnets      4               # If this many subnets trigger, put wildcard
CompAsWild                      # Flag (no value) to list component names in
MaxTrigMsgLen   30000           # maximum length (bytes) of a triglist message;

# Load the next valid trigger sequence number
TrigIdFilename eqk/trig_id.d

#              Installation       Module          Message Types (hard-wired)
GetEventsFrom  INST_NIOSH    MOD_WILDCARD    # TYPE_CARLSTATRIG # REQUIRED.

# Subnet  Minimum to      List of Station.Component.Network.Location
# Number  Trigger         Codes (space delimited)
# ------- ---  -------------------------------------------

Subnet 0  3  STA1.ELZ.UK.-- STA2.HHZ.UK.-- STA3.HHZ.UK.-- STA4.HHZ.UK.-- STA5.HHZ.UK.-- STA6.HHZ.UK.-- STA7.EHZ.UK.01

Here is the log for CarlStaTrig for an event that occurred last night:

20210504_UTC_03:28:45 STA6.HHZ.UK.-- triggered on: 7309.4 at 1620098924.00 count: 3
20210504_UTC_03:28:46 STA6.HHN.UK.-- triggered on: 70647.0 at 1620098925.00 count: 8
20210504_UTC_03:28:47 STA6.HHE.UK.-- triggered on: 70000.7 at 1620098925.00 count: 7
20210504_UTC_03:28:47 STA2.HHZ.UK.-- triggered on: 10732.8 at 1620098925.00 count: 3
20210504_UTC_03:28:48 STA2.HHN.UK.-- triggered on: 15187.7 at 1620098925.00 count: 3
20210504_UTC_03:28:48 STA2.HHE.UK.-- triggered on: 9851.5 at 1620098925.00 count: 6
20210504_UTC_03:28:49 STA6.HHZ.UK.-- triggered off at: 1620098927.00 (on: 1620098924.00) count: 3
20210504_UTC_03:28:49 STA2.HHZ.UK.-- triggered off at: 1620098927.00 (on: 1620098925.00) count: 3
20210504_UTC_03:28:50 STA6.HHN.UK.-- triggered off at: 1620098927.00 (on: 1620098925.00) count: 8
20210504_UTC_03:28:50 STA2.HHN.UK.-- triggered off at: 1620098928.00 (on: 1620098925.00) count: 3
20210504_UTC_03:28:50 STA6.HHE.UK.-- triggered off at: 1620098927.00 (on: 1620098925.00) count: 7
20210504_UTC_03:28:50 STA2.HHE.UK.-- triggered off at: 1620098927.00 (on: 1620098925.00) count: 6
20210504_UTC_03:29:02 STA5.HHZ.UK.-- triggered on: 2274.8 at 1620098926.00 count: 3
20210504_UTC_03:29:02 STA5.HHE.UK.-- triggered on: 5044.2 at 1620098926.00 count: 3
20210504_UTC_03:29:02 STA5.HHN.UK.-- triggered on: 14126.7 at 1620098926.00 count: 3
20210504_UTC_03:29:03 STA5.HHZ.UK.-- triggered off at: 1620098928.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:03 STA5.HHN.UK.-- triggered off at: 1620098928.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:03 STA5.HHE.UK.-- triggered off at: 1620098929.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:14 STA1.ENZ.UK.-- triggered on: 1107.4 at 1620098924.00 count: 9
20210504_UTC_03:29:14 STA1.ENN.UK.-- triggered on: 212.4 at 1620098924.00 count: 7
20210504_UTC_03:29:14 STA1.ENE.UK.-- triggered on: 69.5 at 1620098924.00 count: 8
20210504_UTC_03:29:14 STA1.ELZ.UK.-- triggered on: 14912.6 at 1620098924.00 count: 62
20210504_UTC_03:29:14 STA1.ENZ.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 9
20210504_UTC_03:29:14 STA1.ENN.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 7
20210504_UTC_03:29:14 STA1.ENE.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 8
20210504_UTC_03:29:14 STA1.ELZ.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 62
20210504_UTC_03:29:16 STA7.EHZ.UK.01 triggered on: 80.8 at 1620098926.00 count: 5
20210504_UTC_03:29:28 STA3.HHZ.UK.-- triggered on: 11131.3 at 1620098924.00 count: 5
20210504_UTC_03:29:29 STA3.HHE.UK.-- triggered on: 4036.7 at 1620098924.00 count: 7
20210504_UTC_03:29:30 STA3.HHN.UK.-- triggered on: 63624.7 at 1620098925.00 count: 4
20210504_UTC_03:29:30 STA3.HHZ.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 5
20210504_UTC_03:29:31 STA3.HHN.UK.-- triggered off at: 1620098926.00 (on: 1620098925.00) count: 4
20210504_UTC_03:29:31 STA3.HHE.UK.-- triggered off at: 1620098926.00 (on: 1620098924.00) count: 7
20210504_UTC_03:29:32 STA4.HHZ.UK.-- triggered on: 957.6 at 1620098926.00 count: 3
20210504_UTC_03:29:32 STA4.HHZ.UK.-- triggered off at: 1620098927.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:32 STA4.HHN.UK.-- triggered on: 4441.6 at 1620098926.00 count: 3
20210504_UTC_03:29:32 STA4.HHN.UK.-- triggered off at: 1620098927.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:33 STA4.HHE.UK.-- triggered on: 6031.3 at 1620098926.00 count: 3
20210504_UTC_03:29:33 STA4.HHE.UK.-- triggered off at: 1620098927.00 (on: 1620098926.00) count: 3
20210504_UTC_03:29:53 STA1.ELZ.UK.-- triggered on: 2.9 at 1620098993.00 count: 63
20210504_UTC_03:29:54 STA1.ELZ.UK.-- triggered off at: 1620098994.00 (on: 1620098993.00) count: 63
20210504_UTC_03:30:05 STA7.EHZ.UK.01 triggered off at: 1620098930.00 (on: 1620098926.00) count: 5

Here is the log for CarlSubTrig for that same time window:

20210504_UTC_03:33:43 Trigger ON at 1620098924; initial duration: 2
20210504_UTC_03:33:53 Trigger OFF at 1620098934; duration: 10
20210504_UTC_03:33:53 Total of 1 subnets triggered (1 coincidentally)
   Subnet 0: STA1.ELZ.UK.-- STA2.HHZ.UK.-- STA3.HHZ.UK.-- STA4.HHZ.UK.-- STA5.HHZ.UK.-- STA6.HHZ.UK.-- STA7.EHZ.UK.01
v2.0 EVENT DETECTED     20210504 03:28:44.00 UTC EVENT ID: 7572 AUTHOR: 033091108

Sta/Cmp/Net/loc   Date   Time                       start save       duration in sec.
---------------   ------ ---------------    -----------------------------------------
 STA1 * UK -- P 20210504 03:28:44.00 UTC  save: 20210504 03:28:41.00      13
 STA2 * UK -- P 20210504 03:28:45.00 UTC  save: 20210504 03:28:41.00      13
 STA7 * UK 01 P 20210504 03:28:46.00 UTC  save: 20210504 03:28:41.00      13
 STA5 * UK -- P 20210504 03:28:46.00 UTC  save: 20210504 03:28:41.00      13
 STA3 * UK -- P 20210504 03:28:44.00 UTC  save: 20210504 03:28:41.00      13
 STA6 * UK -- P 20210504 03:28:44.00 UTC  save: 20210504 03:28:41.00      13
 STA4 * UK -- P 20210504 03:28:46.00 UTC  save: 20210504 03:28:41.00      13

20210504_UTC_03:33:54 Trigger ON at 1620098935; initial duration: 2
20210504_UTC_03:33:55 Trigger OFF at 1620098936; duration: 1
20210504_UTC_03:33:55 Total of 1 subnets triggered (1 coincidentally)
   Subnet 0: STA1.ELZ.UK.-- STA2.HHZ.UK.-- STA3.HHZ.UK.-- STA4.HHZ.UK.-- STA5.HHZ.UK.-- STA6.HHZ.UK.-- STA7.EHZ.UK.01
v2.0 EVENT DETECTED     20210504 03:28:55.00 UTC EVENT ID: 7573 AUTHOR: 033091108

Sta/Cmp/Net/loc   Date   Time                       start save       duration in sec.
---------------   ------ ---------------    -----------------------------------------
 STA1 * UK -- P 00000000 00:00:00.00 UTC save: 20210504 03:28:52.00      4
 STA2 * UK -- P 20210504 03:28:45.00 UTC  save: 20210504 03:28:52.00      4
 STA7 * UK 01 P 20210504 03:28:46.00 UTC  save: 20210504 03:28:52.00      4
 STA5 * UK -- P 20210504 03:28:46.00 UTC  save: 20210504 03:28:52.00      4
 STA3 * UK -- P 00000000 00:00:00.00 UTC save: 20210504 03:28:52.00      4
 STA6 * UK -- P 20210504 03:28:44.00 UTC  save: 20210504 03:28:52.00      4
 STA4 * UK -- P 20210504 03:28:46.00 UTC  save: 20210504 03:28:52.00      4

Does anyone have an insight into why there is a double trigger? I appreciate any help.

Thanks,

Shawn

[James C. Pechmann]

Hi Shawn,

     There is a parameter called "Trigger Time to Live"
in the CarlSubTrig and CarlStaTrig station files.  This
parameter specifies "the number of seconds that each
station trigger will be [held] active in CarlSubTrig
after CarlStaTrig reports the station trigger off.  It
allows for the P-wave propagation time across the subnet.

     What do you have "Trigger Time to Live" set to?  If
it is too long, say 10 s as in the example in the
CarlSubTrig manual, then that would explain the double
trigger problem that you are having.  All of the stations
in your example trigger within 2 s of each other and
remain in a triggered state for 1-4 s, as determined by
CarlStaTrig.  But if the "Trigger Time to Live" is 10 s,
then CarlSubTrig will consider them to be in the
triggered state for 11-14 s.  Consequently, the subnet
is likely to re-trigger immediately after the maximum
trigger length of 10 s is over.

--Jim
    

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[Shawn Boltz]

Hi Jim,

Thanks for the suggestion. It is set to the default 10 s, so I will try reducing it and see what happens. As a side note, I got a little bit confused reading the documentation for the sample file as it made it sound like the “trigger time to live” doesn’t actually get used.

Shawn

On May 4, 2021, at 21:51, James C. Pechmann <pech...@seis.utah.edu> wrote:

 Hi Shawn,

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[James C. Pechmann]

Hi Shawn,

     "Trigger Time to Live" (TTTL) is used by CarlSubTrig
but not CarlStaTrig.  But there is a field for it in the
station file for both modules.

     I suggest that you try setting this parameter equal
to the maximum P-wave travel time across your subnet
plus either 3 s or twice the STAtime that you are using
in CarlStaTrig, whichever is larger.

--Jim
 

To view this discussion on the web visit https://groups.google.com/d/msgid/earthworm_forum/8DE0DB77-F296-46EC-8542-41B0514B0E23%40gmail.com.

[Shawn Boltz]

Thanks. This helps a lot.