What's Driving All The Shaking At Yellowstone National Park?

What's driving the recent rumbling in Yellowstone's geologic underpinnings? Photo of Great Fountain Geyser by Jeremy Sullivan.

It's no secret that Yellowstone National Park is volcanic in nature. Still, scientists are raising their eyebrows over a recent swarm of earthquakes that have been shaking the park's underpinnings.

Since December 26 the park has been hit by more than 250 earthquakes that, while not overpowering, have been in the range of a 4.0 magnitude, according to the Yellowstone Volcano Observatory.

The largest of the earthquakes was a magnitude 3.9 (revised from magnitude 3.8) at 10:15 pm MST on Dec. 27. The sequence has included nine events of magnitude 3 to 3.9 and approximately 24 of magnitude 2 to 3 at the time of this release. A total of more than 250 events large enough to be located have occurred in this swarm. Reliable depths of the larger events are up to a few miles. Visitors and National Park Service employees in the Yellowstone Lake area reported feeling the largest of these earthquakes.

While Yellowstone experiences anywhere between 1,000 and 2,000 earthquakes of varying magnitudes each year, the recent swarm -- centered beneath Yellowstone Lake some 3 to 6 miles south-southeast of Fishing Bridge -- is impressive in that its been unleashed in a handful of days.

"This ... earthquake sequence is the most intense in this area for some years and is centered on the east side of the Yellowstone caldera," reports the observatory staff. "Scientists cannot identify any causative fault or other feature without further analysis. Seismologists continue to monitor and analyze the data and will issue new information if the situation warrants it."

For readers adept at reading seismograph reports, you can check out this site, and this site. More on-line data can be found here.

Earth scientists aren't sure what to make out of this burst of activity. At the University of Utah, where Dr. Robert Smith teaches geophysics and also monitors Yellowstone's seismic activity, the professor says it's impossible to say at this point whether the swarm is a precursor to some larger volcanic event.

If you recall, it was just about four years ago that a made-for-TV docudrama about this geologic wonder created some serious buzz about whether Yellowstone, and anyone visiting within a few hundred miles, was going to be blown to smithereens at any moment.

Well, that was four years ago, and while Yellowstone's geologic plumbing has uttered some burps -- minor earthquakes are normal, the Norris Geyser Basin grew a bit hotter than normal in 2003, as did the Artist Paint Pots area did this past May, the caldera is pushing up at a somewhat faster-than-normal rate -- the park is still there.


The Yellowstone Caldera's "three supereruptions occurred 2.1 million, 1.3 million and 640,000 years ago", but "Over 20 large craters have been produced [by hydrothermal (steam) explosions] in the past 14,000 years since the glaciers retreated from Yellowstone, resulting in such features as Mary Bay, Turbid Lake and Indian Pond.".

Few will fail to notice that 800,000 years lapsed between the 1st and 2nd supereruptions, that 660,000 years separated the 2nd & 3rd events, and that it has now been 640,000 years since the last ... continent-scale devastation. While uncertainties of a few thousand years put the possibility of a 4th supereruption beyond our immediate personal concern, it is geologically due 'at any time'.

In terms of the National Parks Traveler website and Parks-aficionados in general, the significance of any sort of sustained or 'patterned' activity within the Caldera-complex is that it will quickly arouse 'national-interest' attention. In addition to a large increase in surface research projects which will entail vehicular and airborne support year-round, it is easy to imagine that more or less extensive exploratory drilling into the formations could be indicated & undertaken.

There are obviously gigawatts of steam energy beneath Yellowstone, and it has been suggested that this energy be tapped, commercially. If rising hydrothermal pressures (which raise security-fears) could be relieved by installing geothermal electrical generating plants, then that may become a recommendation.

Occasional sessions of burping & gurgling under Yellowstone will generate only passing spates of media-reports, but ongoing, 'patterned', or dramatic/scary events will lead to a Cold War-style scientific confrontation at the Caldera (and Park), maybe a little or lots of investigative drilling, and possibly even commercialization of the underground steam.

There are a lot of apocalyptic blog posts appearing at this news, and my newspaper (link below my name) has had an incredible spike in unique visitors since this story broke. I haven't had this many since the peak of tourist and fire season.

Pretty amazing -- a lot of the blog posts are extremely amusing to me, and so I've posted a lot of them.

Jim Macdonald
The Magic of Yellowstone
Yellowstone Newspaper
Jim's Eclectic World


Thanks for pointing to your newspaper. There definitely are some bizarre posts out there in cyberspace. I particularly liked the one titled, "We are all going to die..."

I wonder if there's going to be a run on DVDs of Supervolcano?

Well, Kurt, that part at least is true. We ARE all going to die. I THINK it was Thornton Wilder (I could be wrong) who has (roughly translated) on his tombstone: "I realize everybody has to die. I just didn't think I was going to be one of them..." And I wonder how long it will be before that television special runs again. Maybe tonight? You KNOW they're going to capitalize on this big one. But on the more serious side...I don't want Jellystone to blow up.

Kurt admires the line:

"We are all going to die..."

Hey, wait a minute! Isn't that anthropogenic global warming?!

Death by run-away CO2 greenhousing ... "To hell with the dilithium crystals, gimme all you got, Scotty! - we're heading over the TIPPING POINT!!!"

Yeah, I think it was something like that. ;-)

Lynn Berk quotes Wilder (?):

"I realize everybody has to die. I just didn't think I was going to be one of them..."

Yeah - what he said!

And don't forget, we should all live so obnoxiously long as to one day lament; "If I'd known I was going to live for so incredibly long, I'd have started earlier & worked harder on more of those health-recommendations I knew about all along!" ;-)

It's all Bush's fault!

To consider the new year as we are all prone to do, I've written my two cents on this doom and Yellowstone stuff (and there's many more posts on the newspaper on this on all sides of the doom continuum).

Anyhow, for anyone interested, check out my brand new essay: Yellowstone doom: Imagine better this new year - and by "better" the surprise of the essay isn't that I ask that we imagine better things than doom but rather that we do a better job of imagining. What seems to be quite imaginative yearnings for the Apocalypse to come (or fear of the same) really has been dull and quite predictable.

I at least hope what I've written is very unlike anything I've read so far online.

Jim Macdonald
The Magic of Yellowstone
Yellowstone Newspaper
Jim's Eclectic World