binder declares two events (when actually is a single one)

[Victor Preatoni]

Hi!

hope Subject is not too long, but had no idea on how to describe issue...

The fact is, our live EW system is locating two events very close to each other (in time), but when seismologist analyze the traces, it is actually a single event.

Eg.:

second event: 2024-03-23 00:46:04.319
first event: 2024-03-23 00:46:02.579

To debug the issue, I generated a tankplayer file, played it on a local EW system for debugging, and... a single event was produced!.

I am almost sure the issue comes from telemetry not arriving at the same time, but is something we have no much control in. Also, some signals come from our neighbor, the Chilean volcano observatory, so delays between traces can be in the order of tens seconds.

I have been reading the "Notes on Configuring BINDER_EW", but found no clue on how to solve this issue.

I will appreciate any help.

Thanks,

Victor

PS: I can provide logs and .d files, not uploading them now to do not overwhelm

[Matteo Quintiliani]

Hi Victor,

which version of binder_ew are you using?

I remember that regarding multiple nucleation there was an important fix by Paul in binder_ew from Earthworm v7.10.

Here is the reference to the issue https://gitlab.com/seismic-software/earthworm/-/issues/50

I hope this helps you in the first place. Surely Paul can be much more detailed if needed.

Matteo

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[Victor Preatoni]

Ciao Matteo,

thanks for your answer.

I am checking that both our live EW system and the debug system are using same binder_ew version:

Version: 1.0.41 2022.04.22

Checking source code, seems that I am using the last version, so I was thinking more of a wrong configuration on my side rather than a bug.

[Paul Friberg]

So both systems have the same binder version and binder_ew.d configuration file and stations list? However playback generates only one event, but the live system gave you two events.

Note that I did put in a nucleation prevention filter that you can turn on with the option:

nearest_quake_dist  D T

Where D is distance (in KM) and T is time in Seconds and if a second event nucleates with in T seconds that is less than D km away, it kills the event from being nucleated.

One problem we have seen is that if you use many components, a second event can nucleate on S arrivals. Can you share your binder_ew.d file here?

Regards,

Paul

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===================================
Paul Friberg   p.fr...@isti.com
CEO/Seismologist
ISTI==Instrumental Software Technologies, Inc.
Phone +1.518.602.0001  

[Victor Preatoni]

Hi Paul, thanks for stepping in.

I have attached the .d file

I never realized about the nearest_quake_dist option. I will try it out now.

Thanks!

Victor

[Paul Friberg]

Thanks. It was a new option that was added  to try and stop this nucleation of events when P is assigned to a Shear arrival on the vertical (hard to stop this if using pick_FP or pick_ew with NoCoda setting).

Paul

To view this discussion on the web visit https://groups.google.com/d/msgid/earthworm_forum/25289a0f-fb68-418d-86dc-6a1f2cc9a99bn%40googlegroups.com.

[Victor Preatoni]

Hi all,

just wanted to share my feedback: after implementing the nearest_quake_dist option, the duplicate events issue seems to be fixed!.

Thanks

Victor

[Paul Friberg]

Thanks Victor. Always great to hear feedback after a suggestion. Glad that solved it.

Paul

To view this discussion on the web visit https://groups.google.com/d/msgid/earthworm_forum/d36a44bd-96d7-4762-8d54-8efb2214bfedn%40googlegroups.com.