Sometimes I think that people have an unhealthy obsession with Yellowstone Caldera. Sure, it is big, powerful and the stuff that disaster movies are made, but in terms of a volcanic system that poses a high threat to life/property in the U.S. on a daily basis, it is relatively low. I know what you are thinking (well, some of you):* "How can you say that? Look at how big the past eruptions were*?" Yes, indeed, the previous eruption from the modern Yellowstone Caldera were indeed big, some of the biggest we have identified on the continents (it is still no Fish Canyon Tuff), so I'll give you that. However, looking at the recent volcanic history of Yellowstone, you'd see that these big "doomsday" eruptions are only a very small piece of its activity, so even if tomorrow the caldera began to show signs of imminent eruption, there is a very good chance that it would be a relatively minor eruption - possibly on the scale of the 2008 and onward Chaiten eruption in Chile.
So, why is it that when a fairly innocuous paper comes out, everyone gets all riled up? National Geographichad a piece about a December 2010 article in Geophysical Research Letters by Chang and others called "An extraordinary episode of Yellowstone caldera uplift, 2004-2010, from GPS and InSAR observations". Alright, I can see why it might catch a reporter's attention: "extraordinary episode" combined with "caldera uplift" all in the recent past (2004-2010) seems juicy. Well, dissecting the article it seems that the key findings are (a) a large area of the Yellowstone caldera has been rising since 2004 (b) from 2004-06, the surface was rising 7-5 cm/yr; from 2006-08, rising 4-2 cm/yr and from 2008-2010, rising 2-0.5 cm/yr and (c) the source of this uplift was likely a sill intruding at 7-10 km depth (see figure below). The Yellowstone Volcano Observatory press release about the paper is pretty subdued, which isn't surprising considering that if research like this makes it to publication, then the data in it is "old news" to the scientific community. Whenever you read about a "shocking" new research paper, remember, that data is likely a year or more old and has been vetted by many people in the research community - not exactly breaking events.
Now, should we expect this at an active caldera? Yes! Does this mean that the caldera is going to erupt soon? Maybe! Will it destroy us all? Probably not!
However, much like much news on the internet, information gets run through a massive game of telephone. This news about Yellowstone morphed into more 2012-style doomsday news. Some fine examples:
Tuscon Citizen: Fairly reasonable look at Yellowstone Caldera until you get to the bottom, where the National Park Service assessment of the activity at Yellowstone as being fairly low with no signs of a "catastrophic eruption is imminent" is juxtaposed with the findings in the Chang et al. paper. This is exactly what you shouldn't do as there is no indication in the paper that its findings are in conflict with the idea that a catastrophic is not around the corner.
Daily Mail: The headline alone takes it to another level: "Is the world's largest super-volcano about to erupt for the first time in 600,000 years, wiping out two-thirds of the U.S.?" I can't remember who said this, but if the title of your article can be answered with "no", then maybe you need to rethink the title, or the article in general. Sadly, it gets worse as the potential eruption at Yellowstone is described as "spewing lava far into the sky" and the U.S. will become uninhabitable by "toxic air", then goes on to say that a new "supereruption" could be coming in the "near future". There is much less information about Yellowstone in the article and very little from the original GRL article - heck, it isn't even mentioned. I'm not even sure what the "scorched earth" image is halfway through the article. And other media websites that have picked up this piece have morphed the title to "Largest volcano 'to erupt after 600,000 years, wipe out 2/3 of U.S." Ugh. (This spoof does a good job describing the Daily Mail's coverage)