But if you look at the entire swarm, the numbers do not indicate that much regularity as to be able to draw your conclusion based on such a short time sample.Originally Posted by dgavin
A complete list of earthquakes in the swarm for the last week.
Order of Kilopi
But if you look at the entire swarm, the numbers do not indicate that much regularity as to be able to draw your conclusion based on such a short time sample.
A complete list of earthquakes in the swarm for the last week.
Order of Kilopi
Here's the University of Utah site reports if they haven't already been posted:
Yellowstone Region Press Releases
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Got the plots done, with events of .8 mag and greater, and updated with the last two days of events.
The trends shown from the plots are interesting. There isn't much difference in location (Hydrothermal or Magma activity would usually show a migration of events in some direction). There has been a slight decrease in average depth over time, and a slight decrease in the number of events over the last day.
The swarms appear to occur in bursts, with less activity between those.
So there doesn't seem to be much indication of magma or hydrothermal activity. USGS is indicating it's slip fault activity, but the pattern it's exhibiting is more common of 'Uplift' related swarms. So while it may be in the area of a know slip fault location, the underlying cause is still volcanic, in the form of built up pressures from uplift.
As such the swarm may either cease shortly, or continue tapering off on amount of activity for some time. Usually swarms related to uplift activity can range from a week, to months of time.
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Just a bit of an update on the swarm. The activity slowed down, to the point of only 1 >.8 mag event on the 23, and 6 on the 24th. Yet it seems to have picked up the pace this morning with 4 already.
What is intresting is that are the start of this slow down period on the 22nd, some new seismograph readings showed up. Harmonic tremors, of a much stronger sinatures then the ones noted before. There was one of these on the 22nd, just after 5pm, on the 23th one at 12:45 am, and another set of 3 starting around 5pm and cumulating in the only >mag .8 event of that day at mag 2.1. Another one on the 24th at about 12:45 am again.
Although the larger events were less frequent, the number of smaller event seems consitant at about 1 to 2 per minute. So even thought the larger events slowed down for a bit, the background events did not.
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Ok researched the rather odd timing of the larger harmonic tremors on the seismographs.
They only showed on the one seismograph, and it's close to the west entrance highway (181). So it's not tremors at all, but likely a twice a day heavy hauler type vehicle that seems to have a semi-regular schedule. My appologies on that.
Activity of the swarm continues today, not much new going on with it. As of yesterday there have been over 1271 earthquakes recorded.
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Quake count as of yesterday (26th) is up to 1356.
Today the rate of the small back ground quakes has tapered of from 1-2 a minute to about 1 every 2-3 minutes. Additionaly there have been no more > Magnitude 3 events since the 25th. The reduced activity and magnitudes could be an indication of the swarm slowing down, or an indication of a brief time of quiet. Time will tell.
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Just checked http://www.seis.utah.edu/req2webdir/...llowstone.html and they just had a 3.2 mag in the same swarm area within the last hour (its 226 MST right now)
Makes you wonder. I worry if a swarm seems to be on the "edge" of the caldera, in my mind you would think their would be a natural "weakness" in that area (ring fracture, etc) that could allow mama a path to the surface. Just like the swarm last year: On the other side of the caldera also near the rim. And Norris is also along the rim.
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TWo more over 3.0.
Was the heavy hauler stuff the stuff we see yesterday circa 9:30?
Today's graphs don't show up on the yvo site, I get a broken link.
ETA: Today's graphs are back. Must have been teh innertubz broken.
And we see the same wierdness at 9:30 today, so yeah, I doubt mother earth is scheduling things that way for us
Nice thud at about 11:03. Double slip?
EATA: How close is this epicenter to Excelsior?
Last edited by jj_0001; 2010-Jan-28 at 07:15 PM.
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Quake count as of this morning (28th) is 1497.
Looks like the background quakes have picked the pace back up again as well.
Was the heavy hauler stuff the stuff we see yesterday circa 9:30?
Yep! Its making it hard to pick out harmonic tremors though, as the webicorders don-t have the resolution needed to distingush from short HT's and hauler activity.
Nice thud at about 11:03. Double slip?
Looks like a quadruple burst... I've seen that signature before, but it's not restricted to volcanic areas. I'm not sure the underlying cause of the multiple bursts like that. Maybe one of the forums geologists can chime in on it.
EATA: How close is this epicenter to Excelsior?
Excelsior Gyser i assume you mean? It's right smack in the midst of the swarm area.
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It just looks wrong, compared to anything else, it has an envelope that looks like "coming and then going", which really does look like something really heavy driving down the road.
Heh, yeah, it was double the first time I looked.
Nice thud at about 11:03. Double slip?
Looks like a quadruple burst...
If it's a slip, just some more rock breaking is my guess. And I see no reason to assume it's not a slip.
I've seen that signature before, but it's not restricted to volcanic areas. I'm not sure the underlying cause of the multiple bursts like that. Maybe one of the forums geologists can chime in on it.
Also, it's kind annoying that the one seismograph is off line. Looking just at the relative magnitudes of the various rumbles would be ineresting, even if I can't figure out how to get good time-delay numbers.
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No update on the quake counts today.
The activity breifly subsided for about 4 hours today, and then started back up. Swarms do that occasionally so it really doesn't mean much, other then it happened.
However I have finnaly found /one/ indication that there have been some measured changes to hydrothermal systems occuring at the same time as this swarm.
From Dr. Erik Klemetti's blog
This is also not surprising, swarms often cause breif changes to hydrothemal venting (increases or decreases) which usualy resume thier normal patterens after the swarm is over.4. Finally, although we have accessory anecdotal evidence of changes in the hydrothermal/magmatic system (e.g., Old Faithful isn't so faithful, the long-lived bulging under Yellowstone Lake, etc.), these correlations do not automatically lead to causation.
...
Just because we might see signs of change in the active systems roughly correlated with an earthquake swarm doesn't mean that they must be related. However, it is a good idea to continue look for changes that could end up pointing towards a magmatic causation ... with enough evidence.
I can't find iny information more though, not even what hydrothermal systems these have seen changes at yet.
Order of Kilopi
From the 28th update:There have been 1,497 located earthquakes in the swarm of magnitude 0.4 to 3.8 up to 9AM January 28, 2010. This includes 12 events of magnitude larger than 3, with 111 events of magnitude 2 to 3, and 1,374 events of magnitude less than 2. There have been multiple personal reports of ground shaking from observers inside the Park and in surrounding areas for some of the larger events (for felt reports, please visit http://earthquake.usgs.gov/eqcenter/dyfi/). Earthquake swarms are relatively common in Yellowstone....
...Yellowstone Volcano Observatory scientists still consider that the swarm events are likely the result of slip on pre-existing faults and are not thought to be caused by underground movement of magma. Currently there is no indication of premonitory volcanic or hydrothermal activity, but ongoing observations and analyses will continue to evaluate these different sources.
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So what do you guys think?
Anything to be worried about?
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Nope.
The only thing I worry about with regard to Yellowstone is when can I get back there for a vacation and can I get a room in one of the lodges.
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Haha, thats nice to hearNope.
The only thing I worry about with regard to Yellowstone is when can I get back there for a vacation and can I get a room in one of the lodges.
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Nope. Just be standard earhtquates still appearing unrelated to anything like magma or steam moving underground. As I metnioned earlier it is likely a swarm of EQ's generated by the general uplift at the Yellowstone region.
As to the current status, quake count up to 1660 as of today, and the swarm still appears to be slowing down.
The swarm has it's own webpage now. http://volcanoes.usgs.gov/yvo/public...10/10swarm.php
Check out the RSAM plot about middle of that web page, for a graph of the quakes aplitudes over time.
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Out of curiosity, if the volcano started going into a state that it was going to erupt what kind of signs would we see. Would we some sort of rising cone like Anak Krakatau over years, or would there simply be an explosion ripping the ground open one day.
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Well, a (*&()load of long-period, low-level earthquakes would be a hint that there was magma movement. That, coupled with very rapid uplift (or drop) in parts of the caldera, a lot of small regular quakes as the crust adjusted, etc, would be a none to subtle hint.
Of course, hydrothermal movement would create some of the same symptoms, and is much more likely, but could probably be distinguished over time by the speed of movement of whatever is moving.
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Besides what jj said, there would be some other indicators.
Likely it would start with an EQ swarm much like we are seeing, however, instead of slowing down though it would gradually intensify, and get shallowed in depth. When the harmonic tremors started showing up, lasting minutes to hours (the low-level earthquakes JJ mentioned) that would indicate either hydrothermal or magmatic movement. Next there would be gas emissions (C02 and HSu2) that reach some significant amounts. About at the same time as the gas emissions started, there would be changes in some of the hydrothermal vents. Water temperature increases, increased frequency of geyser activity, changes in acidity and chemicals of the hydrothermal vents. In the case of magmatic buildup, there would be uplift or possibly swelling of an existing feature above the area. In the case of just hydrothermal activity, that would cumulate in what is known as an explosive geyser (these are rarely large).
The swarms would and the harmonic tremors would continue to intensify, gas emissions increase, and the ground begin to deform significantly.
This -could- all come to naught though, if the shallowness of the movement doest reach within the upper 2km of the surface. If it does reach that shallow of a depth, the magma usually would begin to pool and build up more for some time (weeks to years) until at some point the magma can force it's way up-wards, though the now stressed out and fracturing surface above it. At this point signs of Chugging (thing of boiling on a scale thats immense) start up, and gas vents open up on the surface.
If there is enough pressure in the newly formed magma pool, it will eventually erupt, following signals of the magma getting closer to the surface. If not, the gas vents would eventually release enough pressure and vent enough heat that the new magma pool begins to slowly solidify.
Last edited by dgavin; 2010-Feb-03 at 09:07 PM. Reason: Spelling/Grammar
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As of today, Quake count up to 1719 quakes. There was a six hour increase in quake activity yesterday which then settled back down to to current levels.
It also appears that the swarm has changed depth. Starting at the time of six hour increase yesterday, and continuing into today, the depth of the quakes has rather spontaneosly changed from 12-8km depth, to 8-5km depth. There has also been 2 quakes less then 1km quakes with this new burst of activity.
This is most likely a just secondary swarm at a different depth. There was no indication of a gradualy lessenng of depth indicating magma or hydrothermal motion. Still appears to be either a slip fault related, or uplift related swarm.
There is another burst of increased activity going on right now, but at this time no depth readings from it.
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Update:
As of yet the EQ list summary hasn't been updated since late yesterday (2nd).
Additionally a small series of low amplitude tremors, have been picked up by most seismographs in the region, apparent for the other side of the caldera from the swarm, the most notable being at 14:02 which was picked up on seismograph station in western Yellowstone, Tetons and into Idaho. The YSB station seems to be the closest to all these tremor events.
You'll notice I did not say harmonic tremors, these all were only about 2 minutes in duration, there was only about 7 of them, and while the amplitude signature does not appear as a normal EQ would, they also don't seem to be long duration harmonic/volcanic tremors. Without higher resolution data then the webicorders display I'm not able to identify what they are exactly.
I suspect though that the lack of updates to the EQ list, the noted changes one geologist indicated at still unidentified hydrothermal vents/geysers/, and the now odd tremors at another region in the caldera, has USGS busy trying to determine what relation they have, if any.
At this point, two out of the 7 indicators of volcanic activity have been confirmed, with a possible 3rd added today with the tremors around YSB.
At this point I'm willing to step on a limb and say there may be about a 0.1% chance of some sort of eventual activity (hydrothermal or magmatic) at Yellowstone.
This is nothing to get excited over, my personal feeling is the YSB events are unrelated to the swarms. And even if something eventually was to happen, it could simply be something akin to a new geyser opening up, or an old one reactivating.
There just isn't enough data, nor enough indicators to say what is happening at this point, and if the 2/possibly 3 indicators are related events or not.
If the EQ list doesn't pick up by noon tomorrow, I'll email someone at CVO and see if I can find out whats up with that at-least. The Yellowstone geologists may just all be out doing field work at Yellowstone so no one is available to review and update the lists.
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What the heck was that thing at circa 13:20 today, give or take? It seems like it's more widespread, lasted about 5 minutes. Hydrothermal explosion? Or just weird quake?
ETA: It seems to show up earliest at the westernmost sites near Hegben, unless I'm misreading things?
And, maybe a slide or something near the same time at the eastern side? I am guessing there are two events on the YSB trace overlapping?
YMV looks more like traffic.
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That large event was a 5.9 Mag quake just offshore of Fotuna CA, on the Juan de Fuca plate.
Google map of Epicenter
*edit to add*
When you see the wave form taking on the slow oscillation patterns to-wards the end of an event like you saw on the Yellowstone seismographs, that is the indication of a distant earth quake, strong enough that it caused the planet/or parts of it to "Ring Like a Bell".
If it had been a quake in Yellowstone followed by a Harmonic Tremor, the tremor waves forms would be more compressed than those. Tremor wave forms are actually very similar to wind in forest waves forms, and traffic wave forms on the weibicorders. If you have access to the direct feeds (i used to but don't anymore) you can distinguish between those three types a lot easier.
Last edited by dgavin; 2010-Feb-05 at 02:44 AM.
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Aha, and we see some local resonances, or lack thereof at one of the sites.
How come one can not access the direct waveforms? I dare say I could accomplish a harmonic analysis, to say the least.
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I am not sure why, but almost all of the Western US Seismographs are not viewable using the IRIS VASE viewer or the GEE Project viewer. Its a bit iritating to have the webicorders, but not be able to zoom in onto the wave forms when better resolution needed.
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Update as of this morning, Feb 5th:
Quake count is now up to 1771 quakes. Activity of the swarm began slowing again on the 4th, likewise is was all at the 12-8km depth again. The Feb2nd/3rd events at the 8-5km depth may have been a secondary swarm.
Activity today is almost non existent, with only 9 events so far, and all under magnitude 0.2.
The tremors around the YSB seismograph station at other side of the caldera have also seemed to have slowed down to almost nothing.
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Well two days and all has been quiet on the seismographs. The swarm may be over with.
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Update as of Feb 8th: The swarm activity is still very slow. Quake count now up to 1799 quakes.
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The swarm has slowed down even more. At this point i'm going to say that it is likely done.
The tremors at the other end of the caldera at YSB station have continued, but at a much less frequent rate.
I still have no further information on the geothermal changes that one Dr. mentioned on his blog. So it's looking like all three type of events are must likely unrelated, and coincidental in thier timing.
I'll keep monitoring things and try to get a final quake count posted soon.
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Total quake count for the swarm was 1,805 as of the 8th.
It's be very quiet, up until today, where there was a short burst of earthquakes. Plus a signal of slow flault slipage. It looks a lot like a tremor, but only lasts a few minutes. It quieted down afterwards again. Todays events I think will add 20-22 quakes to the total count.
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