Events that occur too close in time link events to clusters that don't belong

[d-chambers]

Some events that occur close in time with other events can be included in the data pulled when each event is correlated against every other event to determine event clusters.

For example, in the following 2 plots:

contains 2 events (although only one is in the catalog).

Most of the events in the cluster associate with the second event, one event, however, associates better with the first.

This results in an alignment of the events in the first plot to the second event in the same plot. Consequently, the waveform in the bottom figure gets poorly aligned, as in this plot of a waveform group:

[gnpang]

I'm thinking if we can add a picker before create cluster to pick the P arrival time then we can trim waveforms from P arrival for create clusters

[d-chambers]

That is a good idea, but if the wrong event is picked it could cause problems. I don't see any way around it though. I will add an option in the create cluster call to use pick times in the same format as those produced by detex.util.pickPhases (a csv, I have attached the one from the basic tutorial for reference) to find the first arrival and trim according to that rather than event origin. The default behavior will still be to use origin times but if the user runs into this issue he/she can use this new option.

Additionally, I am working on implementing a validation method in the subspace class that will re-calculate the correlation coefficient for the aligned and trimmed waveforms of each subspace and discard any waveforms that no longer meet the correlation coefficient requirement for that station. That should remove the events that don't belong but wont help in correctly classifying them.

Thanks for the suggestion!

PhasePicks.txt