Not long after Yellowstone Park was officially created, a small group of campers were killed by Nez Perce Indians on the run from US troops1. More recently, the last time I was in the area, a ranger was killed by a Grizzly Bear (so was his horse) on the edge of the park. A quick glance at my sister's newspaper archives (Lightning Fingers Liz a.k.a. Caldera Girl has been running newspapers in the region for nearly forty years) shows a distinctive pattern of danger in the Caldera, mainly in relation to the lack of turning lanes on highways with poor visibility and other traffic related hazards.
So, no, the Yellowstone Caldera is not especially safe, what with cars, humans, and griz everywhere. Oh, and every now and then somebody falls into a geyser. But you are probably here because you are interested in a different question: Is the Yellowstone Caldera, the volcanic feature, not the natural and cultural landscape, dangerous? In other words, is one of the largest volcanoes to exist on the earth ever gonna blow? Like this?
(Photograph from UFO Digest)
Over the last decade the caldera has shown interesting and sustained activity, with a large number of small earthquakes and a steady rising of the crust. In all, the surface of many parts of the caldera have risen as much as a foot vertically, which is considered to be a lot.
Over the last couple of years, however, the rise of the surface of the semi-dormant super volcano has slowed considerably. It is now thought that an episode of increased activity of magma 7 plus kilometers beneath the earth occurred and is mainly over.
Geologists infer the three dimensional structure of the stuff under our feet (rock, magma, water, etc.) in part by observing energy as it moves through the earth's crust. For example, a geologist might set off a series of explosive charges and measure the timing (and other details) of the shock waves coming from those charges to sensors. This sonar-like approach allows the mapping of underground three dimensional structure. Deep earthquakes resulting from either faults or from the movement of magma are natural experiments that geologists can use to map subterranean structure, so when the numerous extra earthquakes started to occur in the Yellowstone area several years ago, geologists were able to develop a much more detailed three dimensional concept of what the rock and magma looks like underneath the griz and human infested surface of this part of Montana, Idaho and Wyoming.
A recent paper by Chang, Smith, Farrel and Puskas summarizes the last several years of activity:
... measurements of Yellowstone ground deformation from 2006 to June 2010 reveal deceleration of the recent uplift of the Yellowstone caldera following an unprecedented period of uplift that began in 2004. In 2006-2008 uplift rates decreased from 7 to 5 cm/yr and 4 to 2 cm/yr in the northern and southwest caldera, respectively, and in 2009 rates further reduced to 2 cm/yr and 0.5 cm/yr in the same areas. Elastic-dislocation modeling of the deformation data robustly indicates an expanding sill at â¼7-10 km depth near the top of a seismically imaged, crystallizing magma reservoir, with a 60% decrease in the volumetric expansion rate between 2006 and 2009. Reduction of hydrothermal-volcanic recharge from beneath the northeast caldera and seismic moment release of the 2008 and 2010 large earthquake swarms are plausible mechanisms for decelerating the caldera uplift and may have influenced the change in recent caldera motion from uplift to subsidence.2
Don't ever ask a geologist to write up the end of year holiday letter. What does this mean? Two things. First, look at this graph from the University of Utah:
This plot shows the up-down movement of the LKWY GPS station at the north end of Yellowstone Lake. After moving downward about 50 mm (2 in.) between 1997 and 2004, this area moved 90 mm (3.5 in.) upward from mid-2004 to mid-2006. The most recent data shows that as of October 2007 the total uplift at LKWY had reached 140 mm (5.5 in.). Source
Notice that the crust moves up and down all the time, but during the mid 2000's mostly went up. Now, look at this graph also from the University of Utah:
The orange shapes in this image represent the magma chamber -- a chamber of molten and partly molten rock -- beneath the giant volcanic crater known as the Yellowstone caldera, Photo Credit: Wu-Lung Chang. Source
The blob on the top of the box is the outline of the Yellowstone Caldera. The giant orange three dimensional blob down inside the box is the inferred magma chamber beneath the caldera. Now, here we must have a small digression to explain something that people often get wrong. What you see here is a fairly typical arrangement causing volcanic activity (but on a relatively large scale). It is not the case that volcanoes typically come from the earth's magma through the crust and into the surface. Rather, within the crust there are numerous magma chambers some of which come, in turn, from sub-crust magma, others formed within the crust as 'potent geological forces' melt the crust in place. The earth's crust is tens of kilometers thick, but this magma chamber is less than 10 kilometers in depth.
Anyway, look at the red "wedge" thingie sticking in the orange blob. This is approximately the location of fresh magma that has intruded from some other source into the chamber, expanding it, since mid-year 2004. That is the event that happened in the first decade of the 21st century which got everybody all excited about the Yellowstone Super volcano.
In the future, this magma chamber could cause some real serious volcanic eruptions, but here's the thing: Volcanic sources usually have a lifespan, and quite often, it is a lifespan linked to large scale movements of the crust over the much deeper mantle. This is much more obvious when looking at certain oceanic island chains, forming a string of volcanic islands on oceanic crust (which is much thinner than the continental crust). A "hot spot" in the magma will sit relatively in one location while the crust moves over it. Magma chambers will form over the hot spot, and spew out one or two volcanoes, then that part of the crust crust will move move off the hot spot and over time cool, with the volcano eventually becoming dormant. The Hawaiian islands are an excellent example of this phenomenon:
The smallest islands off to one side of the arc of volcanoes are dormant and, indeed, eroding back into the ocean. The largest islands are more active.
Something like this can also happen on land. Look at this:
You can see an arc-shaped sequence of highly volcanic areas that may have picked up their own local magma chambers from a hot spot in the mantle. Over time, any area of the crust affected by a mantle plume should move away from that source of heat and even if it remains a hot spot for some time it should eventually cool down. It is quite possible that the Yellowstone Caldera is a dormant caldera, in the sense that it will not explode violently in the future as it did three times in the past. This does not rule out smaller volcanic eruptions, however. And, at the scales we are speaking of here, a "smaller" volcanic eruption could be the size of Mt. Saint Helen's 1980 blast.
On the other hand, the magma chamber below Yellowstone is large, and recently was re-estimated to be even larger than previously thought by about 20 percent. The information that allowed the new size estimate is a result of the placement of additional senors as part of volcanic research and monitoring ...
... as well as the swarm of data that comes with a swarm of earthquakes, as mentioned above.
This recent research has resulted in the following three dimensional model of the magma underneath Yellowstone:
Compare this to the three dimensional model above. They are totally different scales, the first looking only about ten kilometers deep, the second looking tens of kilometers deep. This huge amount of magma along with the fact that the mass of magma is growing a little now and then (as evidenced by the intrusion of new magma during the last decade) suggests that maybe the Yellowstone Calder has not really moved off of any hot spot and still has a good chance of "blowing." (An interesting discussion of whether or not the caldera is underlain by the kind of "plume" that might feed a major blow up can be found here.)
Also, look at this map showing the relationship between the Yellowstone Caldera (B) and the location of the so-called Yellowstone Volcano Observatory (A) where the geologists watching the caldera live and work:
That's pretty far away!3
If you ask geologists today whether or not they think there will be an "eruption" in the Yellowstone Caldera, they say that yes, there will be, but the chance of it being a major super-volcanic eruption is very low. But, they say that this chance is small in relation to a given human lifetime, not that it is small in relation to a volcanic system's lifetime. In other words, geologists seriously entertain the idea that the caldera will "blow" again at some time in the future, in a super-mega-eruption of some kind. The most likely kind of eruption to happen in this area is a steam-based eruption that is caused by water super-heated by the same volcanic heat that causes the hot springs and geysers of the region. Such eruptions can form craters up to a kilometer or so wide and have been fairly common in the area. Less likely are the more typical volcanoes like Mt. St Helens (or much smaller or even a bit bigger) spewing out some combination of lava, gas, rock, and stuff. But the full-blown blowout of a caldera style eruption, very rare on Earth these days and quite catastrophic, is a possibility. The best summary of these kinds of activities is probably this one.
So, to return to the question at hand: "Is the yellowstone caldera safe?" The answer is complex:
1) Wear a seat belt when driving around in the region;
2) Don't feed the bears and make sure you understand bear safety; and
3) Somebody is going to get blasted by some kind of volcano in the area some day, but even if you live there the chances are it won't be you.
1Chittenden, Hiram Martin. 1985. Yellowstone National Park,: Historical & descriptive
2Chang, W., Smith, R., Farrell, J., & Puskas, C. (2010). An extraordinary episode of Yellowstone caldera uplift, 2004-2010, from GPS and InSAR observations Geophysical Research Letters, 37 (23) DOI: 10.1029/2010GL045451
3I'm joking, of course. The geologists are not really scared. That's just where their home institution is. Right?
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Great article. I remember when someone first realized it was a HUGE caldera....hmmm, why are those mountains missing? LOL. I once got into an argument with the tour guide on Haleakala who told us that it was the world's largest volcano. I told him (politely, of course) that he wasn't even close! I was not his favorite on that tour! :)
It's good to see that anthropologists are masters of all science. Shall I send out the memo to geologists informing them that their services are no longer needed?
Please do inform us when other disciplines become obsolete, we wouldn't want to step on anthropologist's toes, now would we?
In 1959 a 7.5 magnitude quake struck just outside the northwest boundary of the park. This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake; immediately downstream, the sediment from the landslide dammed the river and created a new lake, known as Earthquake Lake. Twenty-eight people were killed, and property damage was extensive in the immediate region.
"I once got into an argument with the tour guide on Haleakala who told us that it was the world's largest volcano."
Largest volcanic mountain. They do have a large pile of rock. Yellowstone kind of scattered its rock around.
arkham: Snark label or not, I find your comment annoying. I have 30 years of experience and several advanced degrees in what is usually termed these days "paleoanthropology." You might be thinking of "cultural antrhopologists" ... which is a common mistake ... who would do better discussing the cultural reactions to eruptions or something. My training is very much rooted in geology.
Having said that it is true that the subsets of geology that I'm "expert" in only somewhat overlap with the study of volcanoes (I've only worked on a half dozen sites or so that are directly involved with volcanic activity). But still, this is not original research I'm presenting in a peer reviewed journal. Jeesh.
Blair: Yes, I've visited that site. Those buried were campers, IIRC, and are still there. I should have mentioned that as an example of untoward incidents, thanks for mentioning it!
Regarding large mountains and volcanoes, there's always this: http://tinyurl.com/7pls2t
Great info, Greg! Those of us who live in the caldera prefer to encourage the idea that it could blow at any moment. That way, if we have annoying house guests, we can make them view the supervolcano film and watch them squirm and decide to move on to Mount Rushmore.
Regarding the 28 people... Although the quake happened during the tourist season, there weren't that many people in the area at the time, I am told. Otherwise the death count would have been higher.
To your list of safety tips please add: "Do not stand near buildings with pitched roofs on a sunny day, November - May."
hey hey Booboo bear.
lets go get us a picinic basket .
Greg, thanks for the insight into that paper.You are aware I hope that the first image is a graph in the shape of a hockey stick which of course makes it invalid?
Sorry, I just had to make a dig at members of the denial-o-sphere when I saw the shape.
Winters are long in MinnySoda methinks, if GaryB has a hockey stick shape embedded in his Weltanschauung.
Excellent post. I knew almost all of the background info, but none of the current research, and am pleased as punch to get the update.
But I have a question about this statement:
Was there ever a period of time when this type of eruption wasn't rare? My understanding (but I am not a geologist) is that they've always been rare, at least on a human time scale. Is there evidence they've actually diminished in frequency? (Not arguing--genuinely curious.)
James, excellent question. That the question comes up is not entirely random: It is something I was thinking about when I chose those words. In the end, I don't know but I have some speculation. When I wrote that I was thinking that they are in fact rare these days, so this is correct, and it may in fact be the case that they were once less rare.
They might have been less rare in recent times for the simple reason that the Earth's crust is thicker now than it has been in the past. That does not really translate into fewer eruptions: Perhaps "supervolcanoes" were less common, then became more common because a thicker crust makes numerious small volcanoes less likely. Or, major basaltic outflows may have been more common rather than large explosive volcanoes.
If you take all known supervolcanoes, there are not too many. If you plot them along side the next category of volcano size, all volcanoes seem clustered in the last six million years or so, and very few before that. Yet volcanic sediments and basalts don't seem to culuster that way. Thus, we are simply not seeing early volcanoes because they are hard to find. Seems strange, but actually it makes sense.
But if you 'log' the time scale on such a chart, the 10 or so supervolcanoes of Yellowstone size become more evenly distributed through time but with an apparent cluster between 1 and 6 million. However, that is probably the same artifact. And, 'logging' is not necessarily the appropriate transformation ... just an approximation.
So, in the end, it is correct to say that "these days" they are rare, because they are. The implication that they were more common in the past is not necessarily accurate.
That volcanism would have a patterned history, overall, with some periods having more than others, is certainly true. If this pertains to supervolcanoes, however, is not to my knowledge demonstrated.
But yes, they were almost certainly always rare on a human time scale. Even if they were more common, they would still be unlikely events.
George@9, you're thinking of Jellystone.
Greg, interesting article, and I'm glad to see it. I do have to comment, though, on your gratuitous slam, "Don't ever ask a geologist to write up the end of year holiday letter."
I know that you know that the text you've quoted is not intended for the general public, but for the professionals, for whom it is eminently readable, meaningful, and information rich. I know that you're kidding. But this is the kind of anti-science and anti-intellectual comment that is partly responsible for the attitudes we see today that harm scientific education and acceptance of science among the general public today. I hope you can avoid it in the future, as it really isn't helpful.
I think that this is my first comment on your blog. My apologies for it being critical, as most of the time I've enjoyed your posts.
GvlGeologist: You make a valid point, and I appreciate your making it, but I don't actually agree. I do not believe that abstracts on peer reviewed articles need to be incomprehensible. They are almost always written as this particular one was, and they simply don't need to be. My comment is not anti-science. It is anti-bad writing, and it is meant to highlight the very thing you point out: That scientists have the belief (and practice) of an inner technical language that is only partly true. Abstracts attached to otherwise well written articles are often damaged by this philoslphy and they don't need to be.
In one quick pass I can make a half dozen improvements in this abstract that make it much more readable:
We measured the relative rise of the surface in the Yellowstone caldera from 2006 to June 2010. The rate of rise had increased beginning in 2004 but decreased during our study, from 2006-2008, from 7 to 5 cm/yr in the northern part of the caldera and 4 to 2 cm/year in the southwest caldera. In 2009 rates reduced even more (2 cm/yr and 0.5 cm/yr in those areas, respectively). Elastic-dislocation modeling of these data indicates an expanding sill about 7 to 10 km deep, near the top of a crystallizing magma reservoir detected through seismic imaging. Reduction of hydrothermal-volcanic recharge from beneath the northeast caldera and seismic moment release by the 2008 and 2010 large earthquake swarms plausibly explain our observations and may have influenced the change in recent caldera motion from uplift to subsidence.
My slam wasn't gratuitous. It was activist! I'm sure with a small bit of work you can make my rewrite even better.
GL @ 13:
To elaborate further, volcanic explosivity is mostly a function of magma volatile content and magma viscosity (which is itself a function of the magma silica content). The early Earth was mostly oceanic crust (low volatile, low silica basalt) which would have limited the possibility of large explosive eruptions.
As the continental masses grew (high volatile, high silica, roughly granite composition), the basaltic magmas had to burn their way through, creating melts of higher volatile content and higher viscosity by assimilation, mixing or heat transfer. These would be more likely to create large explosions when the mamas approached the surface.
And for the record, I took your comment as a wry criticism of the specific writing rather than a general comment about the field.
But, we are watching...so keep your nose clean, kid.
Maybe I'm being overly sensitive about my fellow geologists, but you didn't say, "this particular abstract could be better written". You made a blanket statement about a class of people. Do you really think that geologists, as a group are incapable of writing clearly? That is what you said. Do you really think that geologists, as a group cannot write a funny, casually worded newsletter? (I should note that I write a newsletter every year, and it is not worded in anything like the technical writing that I do or have done in the past.) That is what you said. Do you really think that geologists, as a group write more poorly than other scientists or other technical writers? That is what you implied. Do you really think that geological abstracts are typically more poorly written than you see in typical biological, chemical, or physics abstracts?
Look, I know that I'm taking this far more seriously than you intended. You made a throw-away line. But the line did not need to be in the OP at all. At worst, you could have said something like, "Stripped of the technical jargon, the abstract means...", and gone on with your explanation. But you chose to make a blanket statement about scientists in terms that mocked them. That is not helpful, and as I said before, "...this is the kind of anti-science and anti-intellectual comment that is partly responsible for the attitudes we see today that harm scientific education and acceptance of science among the general public today." I really do hope that we can avoid statements like these in a science blog.
I won't complain about this any more. I'm not personally offended by your comment (well, maybe a little ;^)). Here, it's no big deal. But I had to point this out. Among the general public, this kind of comment is far too prevalent, and it really isn't helpful. How many times have you heard or read about creationists or climate denialists complain about elitism among scientists or complain that they have no common sense. This just feeds that attitude.
Scientists as a group in concert with editors of scientific journals, pretty much produce crap when it comes to abstracts on their papers.
That particular abstract is fairly typical, and I've been guilty of it myself.
This became especially obvious to me (though I had noticed it before and brought it up in public lectures etc.) when I noticed that half or more of the summaries in the new PLoS journals, meant to be for public consumption but written by the authors, were 90 identical to the abstracts and both were unusable. In some fields, "executive summaries" have become popular because the abstracts are unusable. Then, compare any set of abstracts to the press releases that go along with the paper: If the abstract was readable by an intelligent informed person (a science writer) perhaps the press releases wouldn't be so abysmally unrelated to the papers in so many cases.
This is all about making science more accessible, more justifiable to the public, more usable, not denigrating it.
OK, I'm going to comment, not complain.
I see your point, and largely agree with it, especially now that you are saying scientists in general, not just geologists. Part of the problem, I think, is institutional inertia. My advisor for my master's wrote very formally and was pretty wordy, and I picked up that habit from him. If I wrote an abstract or paper in less formal terms, I probably would have been instructed that it wasn't appropriate. Students in general will use what they read as models for what they write, and if they see wordy, obtuse writing as typical of the research papers in their field, then that's how they will write.
This isn't just in the sciences either. I will always remember when I was a freshman, I took an English class titled (I think) "Writing Well" at the same time as a social science class which shall remain nameless. At the same time that I was learning to write well, I was reading some terrible social science papers, full of incomprehensible jargon and other hallmarks of bad writing. I had to write a term paper for both classes. The paper I wrote for the social science class was in the typical style for the field, and was (as far as I was concerned) poorly written. For my English paper, I turned in that paper, and a re-write based on what we had learned through the semester.
I got an A on both.
Another problem is that some papers are simply going to be very technical, and in order to have a fairly short abstract, will have to be jargon-rich and difficult even for the "intelligent informed person" who is not a specialist in the field to understand. It depends on what audience you're writing for. If you're writing for Scientific American, you can be more folksy. But if you're writing for (as a couple of examples of specialist journals in the geosciences) Geochimica Cosmochimica Acta or Paleoceanography, both of which I've published in, it's unlikely that even educated laypeople will be reading them very often, and you can then use the formal terminology characteristic of the field. Are they poorly written? I guess it depends on who's reading them. Their intended audience may find them very readable. But their intended audience may have years of experience in the field as well.
It would be an interesting experiment to have part of the peer review process be that papers must also be run by someone with an English background as well as a science background, just to see if they can figure out what the abstract is saying.
I still think the crack about geologists could have been... written better. :-D
OK, I'll consider revising.
I think you are absolutely correct that this is passed on through institutional (or institutionalized) inertia.
For what it's worth, as only an amateur scientist, I thought the "holiday letter" snark was hilarious. I've tried to wade through these abstracts many a time and went away with my head spinning.
Very nice summary, I think! Two points:
- Volcano enthusiasts will want enjoy Erik Klemetti's 'eruptions' blog over at BigThink. He's written about he media hype around Yellowstone as well.
- Greg, as a fellow scientist (astronomy) I agree with your points about good science writing. It's possible to be accurate and authoritative without being stilted!
- It would suck if it wasn't safe.
Therefore, it is safe.
Isn't that how the dialog goes these days?
Or: Obama says its safe. Therefore teabaggers scream that it is not safe. Or visa versa.
Everything is safe until its not.
Thank you for writing something about this that doesn't say, WE ARE ALL GOING TO DIE! The Yellowstone hot spot is all around fascinating. Something I wish other discussions or papers would talk about more when they talk about the Yellowstone hot spot is its relation with the Snake River Flood Basalts and the active basin and range style faults that cut through the current caldera rim (IE Eagle Bay). Understanding the lava chamber is important, but there are many complex things going on here that are mostly being ignored. Also... don't ride and/or pet the bison.
That graph of up-down movement of the Yellowstone caldera looks suspiciously like a hockey stick. They must have tried to "hide the decline" in there somewhere.
I urge caution in interpreting something so obviously made by eruption mongers.
I apologize Dr. Laden, my snark was not directed at you. I know that I phrased my statement badly. My intent was to denigrate the idea that those of other specialties cannot have an informed opinion outside of their own specific field of study, an idea that has popped up lately in the blogosphere, not to belittle your presentation of a paper with which you have no affiliation.
Arkham: No problem. I did take your comment as a suggestion for me to shut up by a reader who wishes to impose poorly thought out rules of who should be allowed to say what, and what qualifications others have. But I see now that you were presenting a parody of that sort of thing, and we are fully in agreement on this. No apology necessary, we are clearly on the same page.
Note: The apologetic post above under a yahoomess tag was mine.
After reading your response to me and the assumptions contained within, I withdraw my (what was once a) sincere post. Assume much Dr. Laden? Of course I am only aware of one branch of anthropology, being the idiot that I must be for disagreeing with you. Jeesh. Here I was trying to be nice by apologizing. I'm glad I actually read the thread after replying out of guilt. You, sir, are kind of a dick, not to mention being a bit of a twit.
People: Arkham's mention of a Yahowhatever tag refers to a badly behaved bit of code or something in his comment which was removed (did you see the bare HTML bleeding out of the "posted by" box? I made it go away so that's why that part of his post makes no sense.
Arkham, you made a poorly worded and obnoxious post which you suddenly thought better of, and threw in the "snark"label as an afterthought. My reaction to you telling me to shut up and to not speak without your approval was mild. Then, you apologized for having been unclear, then you call me out for having not understood your unclearness, even though I've acknowledged that we are on the same page and I misunderstood your post.
So, your next apology will be forthcoming, I assume.
Or am I assuming too much?
Muy interesante y al menos nos ha quitado en gran parte un susto de encima, tal como nos lo habÃa presentado un programa de televisiÃ³n de amplia audiencia no hace mucho. Saludos:
wat can I say.... Wild Wild West has already Reached the Peak of Knowledge and Education......
Silly question, by why cant the Yellowstone caldera be drilled and the excess pressure releived in a controled manner instead of allowing to build up?
Good question. The ability to drill a hole is roughly inverse to what you get out of it. Near surface steam pressure pockets or mud under pressure can be drilled into (dangerously) and pressure release (but it won't really be controlled (it will be very messy ... see this: http://tinyurl.com/yll3knx). A hole deep enough to penetrate a deeper and more meaningful (as in caldera-eruption size and depth) would take years to drill, would be at the edge of our ability to do so, and once the bore reached the magma the rock around the hole and all the deeper parts of the drilling equipment would melt and the hole re-seal.
Thanks for the reply, but a follow up. Didnt the Soviets drill a super deep bore back inthe 70's? Is the difference here the Soviets didnt hit magma but a bore into the Yellowstone caldera would and this would cause the problems you described?
is this something that is a scientific imposibility or just one that is beyond our ability to engineer it?
Additionally is your point that the likelyhood of this erupting within the next 100 years or so, so small that its not worth worrying about?
I think the USSR did drill a deep hole, the Kola Bore. The target depth was 15K, but they only reached something like 12K meters. Had they been drilling from the bottom of the ocean, they would be tickling the bottom of the earth's crust, but on the continent the crust is closer to 50K. The soviet project was thwarted by heat, and I'd assume that their findings shape the current thinking on drilling into hot spots.
A bore hole the depth of the Kola bore would easily reach the Yellowstone magma chamber, but it would also encounter heat sooner.
I can't honestly say that this is a scientific impossibility. Indeed, maybe we should be trying to do this just for the energy! But from an engineering perspective it would be a nightmare.
Which is probably why we should actually do it.
I think it's going to blow. One big earth quake and BOOM, that thing is going to pop. I've been worried about Mt. Fuji too. Especially with this recent earth quake. I'm surprised it didn't go right along with it. Just a matter of time. It's coming soon.
A bore hole the depth of the Kola bore would easily reach the Yellowstone magma chamber, but it would also encounter heat sooner.