Recent events happening at Grand Teton (South of Yellowstone)

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]

reply to post by Shirakawa


Yeah, actually I was about to ask you about those frequency ranges, so I am glad you explained that. The data in the 4K region had me like

Anyway, just to bring this full circle, I was able to dig up the FLWY station in GEE on the Intermountain West network (IW).

www.seis.utah.edu...

And I have been monitoring it constantly now, as well as cross checking what I am seeing in GEE against the webicorder graph here:

www.quake.utah.edu...

Given what I am seeing in GEE it has become obvious to me that it is wind saturation. I have come to recognize this pretty easy. I also went and dug up some other stuff that confirms that station is sitting in a very wind gust prone spot in Teton Pass, at a high elevation of over 6,600 feet.

So at this point I am in total agreement with you about this. It appears that webicorder is getting smacked pretty good with some high wind blasts that are lasting for hours on end.

Originally posted by hotrodturbo7
Is it normal for an activity to have a quasi repetitive pattern like that?
If no other stations are showing I would say malfunction.

My quote seems dumb now that it is likely just wind noise,
so I reduced it to this, lol.



[edit on 20-8-2009 by Ex_MislTech]