posted on Aug, 19 2009 @ 05:19 AM
reply to post by TrueAmerican
Unfortunately the waveform view that most webicorders provide is not enough to tell what is what on most seismic traces. More than often a more deep
and detailed view is needed, like the spectrum view:
This is FLWY in spectrum view:
img35.imageshack.us...
This is the pure noise section from I17A:
img27.imageshack.us...
Telemetry noise in spectrum view will often look as short and/or intermittent bursts and very wide band signal spikes (in the charts above they would
look like vertical red/white bars going from 0 to the maximum frequency threshold) or as a broadband noise varying in intensity and covering most
frequencies.
Anyway, as I wrote in my last message, probably what is happening on FLWY is a combination of wind and the way the seismometer perceives it.
[edit on 2009/8/19 by Shirakawa]
For comparison, this is a section from AV.RSO seismic station from earlier this year at Redoubt, showing persistent volcanic tremor and a steam
explosion at the end (with an increase of telemetry noise just before it when the light cyan becomes a darker blue):
img7.imageshack.us...
Please note that even though the frequency scale in the image is reported to be 3-4 KHz, the real scale is 0-100 Hz, while on H17A and FLWY it's 0-40
Hz, so half the vertical height of this last seismic trace would roughly correspond to the full height of the other ones. This is a VERY rough and
simple explanation, it's more complex than this.
[edit on 2009/8/19 by Shirakawa]