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About our certain doom from the Yellowstone supervolcano

11 January 2009

Earth was a benign mother during the 20th century, so that we forgot that changes in the physical world are among the most powerful drivers shaping history.  Now we seem to have gone to the other extreme, seeing every change in the physical world as a harbinger of doom.

Here are some antidotes to the nonsense circulating about the Yellowstone supervolcano, from the always reliable USGS.  Odd how so much dreck is circulated on the Internet, when there are these well-written and authoritative reports so easily available.

  1. Steam Explosions, Earthquakes, and Volcanic Eruptions – What’s in Yellowstone’s Future?“, USGS Fact Sheet, 2005 — The best briefing I on the subject I have found; excellent graphics.
  2. Preliminary Assessment of Volcanic and Hydrothermal Hazards in Yellowstone National Park and Vicinity“, USGS report, 2007
  3. Yellowstone Lake Earthquake Swarm Summary as of 8 January 2009“, USGS

Excerpt from #3:

The recent swarm is well above typical activity at Yellowstone. Nevertheless it is not unprecedented during the last 40 years of monitoring. Earthquake swarms within the Yellowstone caldera are typical, with magnitudes occasionally ranging above 4.0. The 1985 swarm on the northwest rim of the caldera lasted for three months, with earthquakes up to M4.9 and over 3000 total events recorded.

Excerpt from #2, page 28:

Although the probability of a large caldera-forming eruption at Yellowstone is exceedingly small, it is exceedingly difficult to make a defensible quantitative estimate of that probability. As there have been three such eruptions in about the past 2,100,000 years, there are only two intereruptive periods from which to gauge any additional possible interval between the third and a potential fourth such event.

  • The first interval, between the Huckleberry Ridge (2.059±0.004 Ma) and Mesa Falls (1.285±0.004 Ma) caldera-forming events, was 774,000±5700 years.
  • The second interval, between the Mesa Falls and Lava Creek (0.639±0.002 Ma) events, was 646,000±4400 years.

A statement, widely repeated in popular media, regards such eruptions as occurring at Yellowstone “every 600,000 years” with the latest eruption having been “600,000 years ago”. This is commonly taken to imply that another such eruption is “overdue”. Such a statement is statistically indefensible on the basis of the extrapolation of two intervals. (Even the simple arithmetic average of the two intervals is 710,000 years, not 600,000 years).

From the line of reasoning outlined here, the probability of a fourth large caldera-forming event at Yellowstone can be considered to be less than 1 in a million, below the threshold of hazards interest unless future premonitory phenomena, probably more severe than those recorded historically in caldera systems around the world (Newhall and Dzurisin, 1988), were to be recognized.

Premonitory indications of an impending major caldera-forming eruption at Yellowstone would include intense swarm seismicity, perhaps localized near the site of an impending outbreak, but initial indications might not be greatly different from those for a smaller eruption.

A magma body large enough to sustain a major caldera-forming eruption would, however, be expected eventually to respond as a whole. By the time seismicity and ground fracturing spread to encompass a larger area, equivalent to a potential caldera and perhaps to outline a ring-fracture system, major eruption might already be well underway.

Based upon the geologic record of the Lava Creek eruption, magma rising to shallow levels almost certainly would produce significant uplift of both a locus of possible outbreak and also a larger area of shallow rising magma. Quite possibly ground fracturing would accompany intrusion to shallow crustal levels and might even begin to outline a ring-fracture system (compare to figure 6). Magmatic gases venting to the atmosphere before any ash or lava were to erupt, including CO2, various sulfur species (but especially SO2), and halogens, might well be more evident and more copious from such a large shallow magma body as it ascends into the brittle upper-crustal zone than would be expected for a smaller body that might lead to a single central-vent rhyolitic eruption.

Although many of the specific premonitory events for such an eruption might resemble precursors to a smaller rhyolitic eruption, the magnitudes would be expected to be correspondingly greater, there might be geophysical activity over an areally large source, and the course of events would be expected to be more complex and of longer duration than for a smaller eruption.

 

Afterword

If you are new to this site, please glance at the archives below.  You may find answers to your questions in these.

Please share your comments by posting below.  Per the FM site’s Comment Policy, please make them brief (250 words max), civil, and relevant to this post.  Or email me at fabmaximus at hotmail dot com (note the spam-protected spelling).

For more information from the FM site

To read other articles about these things, see the FM reference page on the right side menu bar.  Of esp relevance to this topic:

The key post in the series about shockwaves — low probability, high impact events:

Other posts about shockwaves:

  1. Spreading the news: the end is nigh!, 8 May 2008
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4 Comments leave one →
  1. Mongo permalink
    11 January 2009 2:53 am

    I think people like being scared by stories like this. Looking through history you can see a pattern of religions using stories of the punishments sinners would suffer after death and now, with religion losing influence, more scientific tales like this take their place. This is just another case of people believing what they want to believe rather than what is true.

  2. Robert Petersen permalink
    12 January 2009 12:52 am

    First of all: There are many other super-volcanoes around the world. Yellowstone is just one of them and most likely not even the worst.

    Second: The human race is apparently threatened by countless of threats like nuclear war, terrorism, comets and asteroids from outer space, the Millenium Bug, alien invasion from outer space etc. I can hardly keep track of all the threats and yet…we are still here. I feel like Yossarian in “Catch 22″ lamenting all the persons who were trying to kill him in the middle of WW2: “There were too many dangers for Yossarian to keep track of. There was Hitler, Mussolini and Tojo, and they were all out to kill him. There was Lieutenant Scheisskopf with his fanatism for parades and there was the bloated colonel with his big fat moustache and his fanatism for retribution, and they wanted to kill him, too. There was Appleby, Havermeyer, Black and Korn. There was Nurse Cramer and Nurse Duckett, who he was almost certain wanted him dead, and there was the Texan and the C.I.D. man about whom he had no doubt. There were bartenders, bricklayers and bus conductors all over the world who wanted him dead, landlords and tenants, traitors and patriots, lynchers, leeches, and lackeys, and they were all out to bump him off…”
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    Fabius Maximus replies: So what’s your point? Ignore them? Or, perhaps we should imitate Wendy, and believe in faries. It cured Tinkerbell.

    Or we might follow my recommendation in “We are so vulnerable to so many things. What is the best response?” (30 December 2008). Research, thought, do the best we can.

  3. Robert Petersen permalink
    12 January 2009 3:09 am

    I agree that research is a step in the right direction, but I don’t think it constitutes the solution.

    Take for example terrorism. Since 911 research in terrorism has become an industry and each year countless of books (many well-intended and well-written) are published on the subject. Since the very definition of terrorism is unclear (as far as I know there are more than a hundred definitions of what a “terrorist” is) that industry can survive for a long time. Especially because political leaders are willing to shovel huge amounts of money into that industry. As a Ph.D.-student without a scholarship studying civil-military relations I am keenly aware of were the flow of money is going.

    My point is that at some point a leader – it could be the president of the United States – should make a decision. It will be more or less subjective and chances are that he or she might be wrong. President Bush was briefed back in August 2001 on the threat of a possible terrorist strike against the United States. He listened to the briefing delivered by a guy from the CIA and at the of the briefing he rose up, told him “all right – now you have covered your ass” and then left the room to go out fishing. Everybody can see how wrong he was. But on the other hand: If one of us were the president of the United States back in August 2001 would we have reacted differently? I am honestly not sure that I would have thought that the idea of a Bin Laden-strike inside the United States was anything else than the usual “high impact, low probability”-threats we hear about all the time.
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    Fabius Maximus replies: What is the question, to which you discuss “research” as the solution? I do not see the context of your reply.

    On the other hand, you implicitly raise a powerful point — one that applies to terrorism as well as climate science. Are we doing research in a useful fashion? The academic model — thousands of independent, small-scale projects — produces astonishingly little hard results when studying complex phenomena.

    I have said the following many times, in different words for different contexts — but I believe it is vital for America’s success in the 21st century, due to the multi-disciplinary and complex nature of our challenges (source):


    One reason for our difficulty grappling with 4GW is the lack of organized study. We could learn much from a matrix of all insurgencies over along period (e.g., since 1900), described in a standardized fashion, analyzed for trends. This has been done by several analysts on the equivalent of “scratch pads” (see IWCKI for details), but not with by a properly funded multi-disciplinary team (esp. to borrow or build computer models).

    We are spending trillions to fight a long war without marshaling or analyaing the available data. Hundreds of billions for the F-22, but only pennies for historical research. It is a very expensive way to wage war.

  4. dosco permalink
    12 January 2009 4:56 pm

    I have mixed feelings about “studying 4GW.”

    On the one hand, study is a good thing in order to develop more understanding.

    On the other hand, there is the military-industrial machine that will do what it wants, when it wants, and to hell with the research.

    I was an officer in the USAF in the 90s. To promote to Major, one had to complete the compulsory Professional Military Education *and* complete a Master’s Degree. Funny thing was that I couldn’t see much impact (e.g. improvement in effectivenesss) from all of this education (of course, I was a low ranking 0-3, so what did I really know?). One irony was the “shock and awe” campaign at the outset of OIF … I harkened back to my ROTC education and discussions we had about the theories of Trenchard and Douhet, and how WW2 dispelled the notion that strategic bombing could “break an enemy’s will to fight.” And “shock and awe” was going to break the will of the Iraquis — yeah, right.
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    Fabius Maximus replies: Thank you for sharing your experience. Martin van Creveld shares your opinion of modern military education. You might find of interest his brilliant 1990 book “The Training of Officiers — from military professionalism to irrelevance” (110 pages).

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