PSN-L Email List Message

Subject: Re: Uploaded files
From: rsparks rsparks@..........
Date: Sat, 02 May 2009 09:23:21 -0700

Hello Thomas,

I thought I would give some feedback to your question about uploaded
files.  No doubt each of us
has a different goal when we look at traces generated by others, but my
questions are usually "Did they
capture a quake?" and "What did the wave look like there?".

The two questions may call for two different traces.  Filtering
frequently helps display the quake better,
eliminating some background noise.  On the other hand, filtering always
reconfigures the raw data so
that the original wave is no longer visible.

I will continue my comments as interjections into your text:

psn-l-digest-request@.............. wrote:
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Uploaded files
> From:    Thomas Dick 
> Date:    Thu, 30 Apr 2009 09:19:17 -0500
> I'd like to open a new topic and maybe get some feedback as to what my 
> files should contain for users of the PSN network. I know what I like to 
> see in the presentation of my files but...
> 1. just how much data show be sent; I usually crop down to about two 
> minutes before the arrival of P and then include at least some of the LR 
> waves. Is this enough? I see some files are much longer than 
> there a reason.
A M9 quake will shake the world for hours.  One M9 was recorded on my
instrument for over 4
hours.  I guess how much file you include depends upon what you are
trying to show your viewers.
> 2. some deep quakes don't show any LQ or LR .... what good is it to show 
> this time frame?
I make the assumption that no trace means no data recorded.  Why use the
> 3. should data containing erroneous spikes be uploading if the rest of 
> the file is good .. I haven't been
Contaminated data SHOULD be discarded.   The viewer should be able to
expect the data to be
free of extraneous events to the best knowledge and ability of the
posting station.
> 4. my location is noisy; is there any value to the users of PSN  if 
> files are filtered, like 2 pole, .5 low pass and .05 high pass for a 5.6 
> mag quake 1600 miles away
I prefer no filter, just the raw data.  Then I can filter the event if I
so choose.  If the event is posted
with the "volume" format available in WinQuake, then both filtered and
unfiltered traces can be
posted/viewed on the same screen.
> 5. do programs that in hence wave forms created by certain weaknesses in 
> equipment (like short period verticals data being extended) serve a 
> positive aid to users of this network
I think the availability of such an enhancing program is very valuable
to demonstrate what a more
capable instrument might display.  I prefer not using such a filter
every posting because filters hide
the raw data.
> 6. does the PSN group have any "Elmer's" that would have time to 
> critique uploaded files and answer some questions
I guess we are all "Elmers" in the sense that all of us are learning as
we go along, and can share what
we have learned.  Chris, Bob, and Larry are particularly skilled and
have generously shared in the past.
Thanks to them and many others who have contributed to this hobby.



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