PSN-L Email List Message

Subject: Re: WinQuake
From: Thomas Dick dickthomas01@.............
Date: Tue, 10 Mar 2009 07:01:48 -0500

Geoffrey wrote:
> FYI:
> There Is Only One Way I can Get Winquake to
> see right times for my data.
> It is necessary to crop the data to the nearest
> second before giving it to Winquake.
> No matter what I do WQ will not see fractions of seconds
> for the start time.
> No matter what the precision is of the numbers
> WQ only will show the first sample to a whole second.
> Like if I tell it 23:49: 20.4 for the first second
> it will show only 23:49:20 for the first sample
> SO you must run your data until it gets to
> 23:49:21 then crop it from there to the end
> before giving it to wq and tell wq
> it is 23:49:21.0 and you can forget the fractions
> your start time may be a couple milliseconds off
> but WTHeck.
> Otherwise if you do not do this things just aint right.
> Also, the various filters in the WQ3 FFT used to work fine
> but since installing the new WQ3  those filters dont work (all grayed 
> out) ??
> What am I doing wrong ?
> cheers
> geoff
Geoff and all ....

I know I don't belong in the same theater as most of you -- let along 
the same stage. This is going to show my ignorance. I am confused about 
the value of your pursuit into "It is necessary to crop the data to the 
nearest second before giving it to Winquake".

 Here is where I am coming from;
1. when you try to get that close with the timing issue on P, aren't you 
ignoring the timing errors caused by internal computer timing 
inaccuracies and delays caused by getting the timing signal from the 
satellite or whatever your  source is
2. the time of arrival tables for earthquake waves that are used are not 
set in stone ---- they are averages ..... are you taking this into 
consideration ...
3. are you also pursuing the reaction time delays within the seismic 
unit as well ... just how long does it take for you units to show the 
first arrival of P
4. and finally, what about the inaccuracies within the graphics display 
of the computer .... what degree of definition are you using and will 
this effect timing

I am NOT attacking your efforts but trying to appreciate where you are 
headed with your efforts.

Yours, TomD

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