[Antelope] question regarding dbdetect

[Francesco Civilini]

To whom it may concern,

Is it possible to use the program dbdetect in Antelope to  
automatically mark first motion and second motion arrivals in  
segmented strong motion event data?

I?m currently working on a project that uses antelope to view and  
analyze segmented event strong motion data. We can use dbpick function  
to mark the starting time of the first motion as well as the secondary  
motions (P and S waves). The goal is to ultimately be able to make  
this process automatic through use of the dbdetect program.  However,  
the parameters of dbdetect (sta_win, sta_min, etc), are insufficient  
to make this process automated.
	This is because each waveform has unique amplitudes  that vary by a  
large margin. The detection uses the parameters STA (short time  
average) and LTA (long time average) to calculate a ratio to compare  
with a threshold parameter. If this ratio is greater than the  
threshold, a detection occurs. This ratio, however,  varies greatly  
depending on the amplitude of the specific waveform.  The result is  
that the ratio might be sufficient to trigger detections in some  
waveforms but not in others. For example, a large ratio will trigger  
detections in waveforms with large amounts of high peaks in frequency  
amplitude, but not in a waveform with very low peaks. The similar  
problem occurs when the ratio is made smaller: there are no detections  
in the waveforms with the high peaks.
	Are there any papers or documents that regard automated, strong  
motion demarcation using Antelope that could provide a clue to solving  
this problem?

Thanks,

-- 
Francesco Civilini
fcivilini at umail.ucsb.edu