Seismograms are shown latest first. All seismograms are ©IRIS/USGS.
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These run from 01 Nov 2011 (305) to 30 Nov 2011 (334). You can see the individual image by right clicking and opening in a new tab/window. For technical reasons this is not a gallery.
See below the thumbnails for any detailed analysis of individual days.
14 Nov 2011 Monday
The big signals may be rock fall or glacier move. They don’t quite fit the earthquake signal yet they do sound like it in the waveform which leads me to think rock. None match any declared earthquake.
Likewise the spectrum is ‘fatter’ than an earthquake signal.
05 Nov 2011 Saturday
There is something odd about these long drawn out signals. I have listened to many ‘pipe-cleaner’ or ‘caterpillar’ signals on Yellowstone seismos and they are 100% electrical and no doubt about it. I have also listened to extended signals from electrical interference from various sources, and all of these I recognise without too much difficulty. I can also determine trains, but these signals are not any of these.
The sound is fairly evenly spread between 0 and 20 Hz and then drops off to nothing above 50 Hz. These can be spread over as much as 20 minutes and generally build quickly but end abruptly. Not actually a dead stop but a very rapid reduction.
It sounds like a long rumble and there is not any electrical noise or any other interference. It sounds to be completely natural. Guess you would not expect electrical you might say, this is Glacier Peak and remote. Yes, very true BUT….
This signal appears at:
|Day 297 [Mon]||18:40||Faint|
|Day 301||??||Unknown – windy?|
|Day 303 [Sun]||??||Partial?|
|Day 304||No||Nothing at all|
|Day 306||??||Unknown – Wind?|
|Day 310 [Sun]||18:30||Strong and longer|
This basically is just too coincidental to be natural so despite the fact that it sounds like a seismic type rumble I have to suggest that it is not. Earthquakes, glaciers and/or rock slides just do not behave like that.
Clearly it cannot be a heater as that would have to come on as required and not a pretty regular intervals 24 hrs apart. It is also not a transmission burst artefact as transmission is continuous.
It is a mystery that perhaps only a seismologist familiar with the station can resolve.
I shall not be attempting to pick out individual local quakes as it is just way too time consuming but I have worked out a way of processing the full days signal on around 30 minutes in such a manner that I would be able to detect harmonic or volcanic tremor should it occur. Basically a pass through a Fast Fourier Transform at high speed (100x)
Results for 5th November – Nothing of any importance.
Of interest: All three of the local (Cascadia) earthquakes can be seen. See annotated version of the seismogram.
09:26 approx Small micro-quake local to Glacier Peak. From the P/S separation I estimate somewhere around 5km away.
04 Nov 2011 Friday
Full day frequency analysis. The big telemetry/calibration spike has been removed for this. This frequencies are more towards the higher end of the normal earthquake spectrum.
17:08:16 Small earthquake – distant. Comes immediately after a pop.
17:14:13 Looks like a quake signature but is rock fall or similar. 1 second duration
Preliminary analysis of the ‘bottle-brush’ that starts around 18:25 and ends at 18:42. These are the raw data with no filtering.
Possibly, as has been suggested, the glacier on the move. It certainly has the sound of that complete with pops. Interesting that whilst it covers nearly 20 minutes the drop off at the end is rapid followed by a ‘pop’. Listen for yourselves at 20x speed. (Filtered Low pass 6Hz)
The quake at 09:59:45 approx is also visible on the Mt St Helens, Rainier, Hood and The Trough seismos.
03 Nov 2011 Thursday
Preliminary analysis of the blue spike at ~07:49:30 is that this is probably an ice quake and not an earthquake. The frequency is too high.
You can see in the spectrum that this is pretty much all above the 5Hz level
Remainder of analysis shortly
02 Nov 2011 Wednesday
Analysis (All times are approximate)
03:25:40 (Red mark) Small distant earthquake with clear P and S
03:29:11 Magnifying glass needed but it is a very local microquake with <0.1 sec P/S separation at 5x speed.
04:50:29 This is probably the event at 04:49:59 UTC San Juan Islands Region, Washington which was just 147 km from the seismo. That give about 6 km per second travel time so that is just about right.
04:50:15 (Black) Difficult to say. 2 distinct events – both local. It sounds like a small quake and then either another or perhaps avalanche/rock fall but I doubt it is consequential upon the first.
Nothing but wind and pops until…
15:36:11 Very distant and not easily discerned but has a heavy 2 Hz component and may be the 6.2 Pacific Antarctic ridge quake but I am not sure the timing is quite right.
Nothing much else to see for the rest of the day other than wind and noise and pops.
01 Nov 2011 Tuesday
The large blue signal is possibly an avalanche or rock fall. Whilst it looks like an earthquake a closer analysis shows that it is not a seismic signal as such.
Analysis from 00:00:00 UTC to 09:00:00 UTC GPW.UW..EHZ.2011.305
00:34:03 Distant quake – possibly N Cali
00:39:54 A more local quake but not immediately by the seismo
00:51:36 Distant small quakes – hardly audible.
01:07:53 Definitely a small local quake to the seismo with the double beat (P/S) clear.
01:13:03 Distant small quakes
01:46:56 Looks like a quake on the seismogram but sounds like a monk’s gong!
02:03:46 This and other similar sound like the sharp knock from tree root rock – probably ice.
02:39:52 Small almost local quake
02:47:34 Whilst this looks like root/ice it is a very small pretty much local micro quake. Clear p/s
03:08:33 Far distant quake follow by a couple more.
03:52:08 Reasonably local larger quake (but probably sub 1.0)
03:58:55 As above.
05:07:47 Slightly larger reasonably local quake but not right under the seismo.
05:49:13 Sharp small local quake very close to seismo. The drawn out signal just before this does not sound local, if indeed even a quake. Could be wind.
06:06:32 Two localish quakes close coupled that sound just like a hearbeat! Nothing of any note until
06:57:47 Sharp small local quake followed by a larger one at 06:58:54
08:14:55 You can hardly see it on the seismo but is a very short local ‘tap’ – probably a microquake.
08:16:28 A series of about 6 small quakes not immediately close to the seismo. Could be some distance from the signatures.
Generally many very small rumbles that could be wind and actually in the final analysis not so many sharp tree ice pops as it first appears on the seismogram. The rumbles seem possibly to be increasing. Probably a storm incoming.