Yellowstone Melting Road and Seismic Swarms — Reality Check
© 2014 by Linda Moulton Howe
“Underground gas pressure can build up and these little swarms
are kind of Nature's pressure release valve. The pressure gets a little too high,
the earthquakes pop off — sometimes for just a day, which was the case
in these July 5 - 14, 2014, (off and on) swarms.”
– Jake Lowenstern, Ph.D., USGS, Yellowstone Volcano Observatory
Yellowstone map of historic caldera-forming catastrophic events
2.1 million years ago, 1.3 million years ago and 640,000 years ago.
Graphic © 2000 by Robert Smith and Lee Siegel, Windows into the Earth.
The Yellowstone Caldera measures 34 miles by 45 miles in area, the residue of three
catastrophic caldera-forming magma explosions in which the third one 640,000 years ago
disgorged enough white molten rock to cover the entire state of Texas five feet deep.
July 17, 2014 Menlo Park, California - On Thursday, July 10, 2014, Associated Press headlined, “Yellowstone Road Melts — Sites Closed.” A photograph with the breaking news shows a seriously melted asphalt road called Firehole Lake Drive that loops around some Yellowstone geysers, including Old Faithful.
Google pointer marks Firehole Lake Drive that loops around some Yellowstone
geysers and has been melting since early July 2014, from geothermal heat.
Firehole Lake Drive in Yellowstone National Park has been melting since early July 2014
from geothermal heat. Image July 14, 2014, courtesy National Parks Service.
Road melting in the park happens periodically as magma moves around under the ancient volcanic caldera. Recently on the internet, there have been dramatic postings that “gas levels are higher than ever at the Yellowstone Supervolcano and a rise in the ground under Yellowstone lake.” Websites have warned that gases such as hydrogen sulphide and sulphur dioxide are rising — indicating that very soon the Yellowstone volcano will erupt. But scientists say that is not true.
Yellowstone Eruptions in History
— The last big volcanic eruption was 70,000 years ago. That was lava coming out of the center of the caldera similar to the island of Hawaii's periodic volcanic eruptions.
— The last big caldera explosion was 640,000 years ago. The difference between a volcanic eruption and caldera blowing up is size and power. The volcanic eruptions with lava flow are confined to a smaller area inside the caldera that is 34 miles by 45 miles in size.
But the caldera-forming explosions were catastrophic — literally pouring enough molten magma from inside the Earth to cover the entire state of Texas 5 feet deep. That kind of destructive force has happened only three times:
— the first was 2.1 million years ago;
— the second was 1.3 million years ago;
— the third and last time was 640,000 years ago.
Geologists average that timeline out to a major caldera-forming event every 730,000 years. So if Mother Nature's clock kept up a regular cycle in the mantle's eruptions, Yellowstone should be safe for another 70,000 to 90,000 years from now.
One geophysicist who spends his life studying Yellowstone gas chemistries, geysers, melting roads, seismic swarms and up and down rise of park land is Jake Lowenstern, Ph.D., Research Geologist for the U. S. Geological Survey and Scientist-In-Charge at the Yellowstone Volcano Observatory based in Menlo Park, California. This week I asked him why there are these repeating catastrophic caldera blasts in Yellowstone and whether he expects any dramatic eruptions in the park during this 21st Century.
Jake Lowenstern, Ph.D., Research Geologist, U. S. Geological Survey, and Scientist-In-Charge, Yellowstone Volcano Observatory, Menlo Park, California: “Yellowstone is an interesting place. The entire hotspot system has been active for about 16 million years. There are a whole chain of volcanoes that are stretching from northern Nevada all the way to the present day Yellowstone. Each one of these volcanoes over the last 16 million years has had its own lifetime where it started up. It had several large eruptions and then eventually it died and cooled and got buried by lavas to form a flat plain.
Yellowstone is the most recent. It's been active for the past couple of million years. It's probably moving on its way out. It's a question now of whether a new one (volcanic system) will start to the northeast of Yellowstone. Then, of course, is the question: Is Yellowstone still active? Is there a potential to have new eruptions at Yellowstone? Could there be another of these giant eruptions at Yellowstone? Those are all questions that we have opinions on, but nobody can answer.
IF IT WERE ON THE SAME CYCLE AS BEFORE — 2.1 AND 1.3 MILLION YEARS AGO AND 640,000 — IT WOULD BE ANOTHER WHAT (LENGTH OF TIME) BEFORE IT WOULD BLOW UP AGAIN?
Oh, I think if you do the math, it comes out to more like 730,000 year cycles, so that means we have another 70,000 to 90,000 years to wait before we would have one of the big eruptions. But there's no clock down there. It doesn't quite work like that. There have been numerous large eruptions since the last caldera-forming eruption that could have decreased the likelihood of a new eruption now. And it's possible we'll never get another big one at Yellowstone, but certainly somewhere on Earth, we'll have another super eruption at some point in the future.
Internet Yellowstone Warnings -
Always Need Science Reality Checks
Many web warnings are about “Extinction Events.”
Geologists and geophysicists don't know
if the Yellowstone caldera ended its catastrophic magma building 640,000 years ago or not.
But most scientists do not expect a big caldera-forming explosion at Yellowstone Park
in the 21st Century — and perhaps not for another 70,000 to 90,000 years.
WHAT ABOUT ALL OF THE WEB STORIES AND THE TWEETS AND THE EMAILS ON A REGULAR AND PERIODIC BASIS FROM ALL KINDS OF PEOPLE — SOME WHO LIVE IN THE WYOMING REGION AND THERE ARE ALWAYS REPORTS THAT THE SULPHUR READING IS THIS AND RUMBLINGS ARE HAPPENING THERE. IT IS AS IF THERE IS A CONSTANT BUBBLING OF WARNING ABOUT YELLOWSTONE PARK.
Well, some of it is based on fact and some of it is based on fiction (laughs), so you have to be careful when you evaluate what you're looking at. Certainly the last few years we've had plenty of activity at Yellowstone. We've had a number of earthquake swarms. We had one earlier this year and we even had one this past weekend (July 5-6, 2014). It was east of the lower geyser basin getting towards Mary Lake. There were, I think, on the order of 50 small earthquakes. The largest was somewhere in the neighborhood of 2.5 to 3 magnitude. Most of the other events were much smaller. I'm not aware that anybody felt any of the events.
Why So Many Seismic Swarms in Yellowstone?
July 17, 2014, seismic swarm list of small magnitude earthquakes
between July 11 and 15, at Yellowstone Park, Wyoming.
Source: Yellowstone Volcano Observatory - Monitoring.
WHEN THE SWARMS HAPPEN AND KEEP PERSISTING, WHAT DOES THAT MEAN TO YOU? WHAT IS CAUSING THEM?
Well, we generally think there are fluids — including the waters and carbon dioxide — that are moving around. They are coming off of the deep magma and they are rising and we tend to think of pressurization occurring. So, the rocks are tight. They don't always allow the fluids to get out. Underground gas pressure can build up and these little swarms are kind of Nature's pressure release valve. The pressure gets a little too high, the earthquakes pop off — sometimes for just a day, which was the case in these July 5 - 14, 2014, (off and on) swarms. We've also had a long-term swarm going on north of the caldera. It was quite active for most of the early part of the year. It lasted literally months of a few earthquakes per day.
Then we had a big earthquake of magnitude 4.8, and that kind of seemed to top things off. After that period of time, the swarm trickled off. There's still been some events in that area, but it's been much less active. So, it's basically pressure release.
640,000 Years Ago:
“Catastrophic Eruption” of Yellowstone Caldera
WHAT EXACTLY HAPPENED 640,000 YEARS AGO?
There was a large build up of magma beneath the crust, maybe three or four miles down beneath the surface of the Earth. It was filled with white molten rhyolitic magma, so meaning that it was mostly molten rock and it erupted. It erupted catastrophically over a fairly short period of time — perhaps days and probably no more than a year or so. In that time, about a thousand cubic kilometers of material came out of Yellowstone. That amount of material you could envision is enough to bury the state of Texas about 5 feet deep. If you just put everything that erupted just on the state of Texas, that's how deep it would be.
So, it's a huge amount of material and most of it ended up on Yellowstone. Some of it ended up in the area surrounding Yellowstone and some of it goes a distance in the air. You can find Yellowstone ash in the Gulf of Mexico from the deposits coming down the Mississippi River.
So, it was a big event and those kinds of eruptions have happened in Yellowstone. They've happened in the last 100,000 years in New Zealand and Indonesia.
What Would Happen in Yellowstone Park
Before and After Caldera Explosion?
WHAT WOULD YOU BE LOOKING FOR NOW IN THE 21ST CENTURY THAT WOULD SAY TO YOU: YELLOWSTONE IS GETTING READY TO DO SOMETHING BIGGER THAN SWARMS OR JUST RISING IN A BULGE?
Well, we'd want to see a whole lot of uplift and we'd want to see it everywhere at Yellowstone. We do see uplift in general, but it tends to be relatively modest amounts of uplift — meaning that the ground is moving up. The largest recent episode was about 25 centimeters, or about 10 inches of uplift over a broad region of the caldera, which is a huge area. But to actually make the caldera to erupt, we would probably need a whole lot more than that and much faster movement. At the same time, we would expect to see swarms of earthquakes all over the caldera, not just in individual places.
SO, SHAKING THE WHOLE CALDERA.
Yeah, that is what we believe would be required to get magma actually out of the ground.
And then the final thing that we would expect is that we would combine both of those things with hydrothermal explosions. So, we've got boiling ground water everywhere at Yellowstone. As soon as you start to send magma, which is 800 degrees Centigrade, 1500 degrees Fahrenheit — if you send that up towards the surface and you hit groundwater and the groundwater is already boiling, you're going to get massive steam explosions.
So, you combine the steam explosions with the earthquakes and intense uplift — then we're worried. (laughs) And it's something that we would not be shy about talking about. We have our alert level system. We put out information statements all the time. If anything got worrying, we would certainly be working with all the landowneres there to make sure that people were safe.
HOW WOULD YOU DO THAT? HOW WOULD YOU MOVE PEOPLE IN THE STATES OF MONTANA AND WYOMING AND THAT SURROUNDING REGION?
The first thing is that we don't know what kind of eruption we would have. You wouldn't be moving people away from those states unless you were sure that there was going to be a caldera-forming eruption because the last forty eruptions at Yellowstone have been lava flows that are very local in nature and you'd only be worried about closing individual roads and closing hotels.
You wouldn't really be in the situation of moving state's full of people unless you really were sure that something huge was going to happen. That's a national program. That's not something the USGS (U. S. Geological Survey) does. We provide the volcano warnings; we're not emergency responders.
WHO NOW IS AT THE TOP OF THE PECKING ORDER IN THOSE KIND OF DECISIONS? IS IT HOMELAND SECURITY? OR THE DEPT. OF DEFENCE? OR WHO?
Well, probably all of the above. Normally, you have an incident command and the incident commands are for forest fires or other incidents. It would probably depend on the scale. Normally, the park service or the forest service, because they are the land owners, they would be the ones who are in charge. If it got large enough, then it might be some other organization such as Homeland Security or the Department of Defense.
Would Yellowstone Caldera Blast
Cause A “Nuclear Winter”?
IF YOU HAD ALL OF THE CHARACTERISTICS THAT WOULD BE BEHIND A CALDERA-FORMING EXPLOSION IN YELLOWSTONE, WHAT IS THE WORST CASE?
The worst case would be like something that happened in the previous times, the 640,000 eruption; or the 2.1 million years eruption. Those were very large eruptions, similar to the Toba eruption that happened 74,000 years ago in Indonesia.
[ Editor's Note: Wikipedia - The Toba supereruption was a supervolcanic eruption that occurred some time between 69,000 and 77,000 years ago at the site of present-day Lake Toba (Sumatra, Indonesia). It is one of the Earth's largest known eruptions. The Toba catastrophe hypothesis holds that this event caused a global volcanic winter of 6–10 years and possibly a 1,000-year-long cooling episode.]
They put out a lot of ash and they are major disasters. They are the kind of thing that is going to affect our ability as a civilization to survive. They are big events and they do happen on a geological timescale. But they don't happen on a general lifetime scale the way that we normally think.
IF THAT OCCURRED, WOULD THE PROVINCES OF CANADA TO THE NORTH — AS WELL AS HALF A DOZEN STATES OR SO — WOULD THEY BE DECIMATED?
Anything within 500 miles of Yellowstone would certainly be highly impacted.
WITHIN 500 MILES. AND BEYOND, THE WHOLE PLANET COULD BE PLUNGED INTO THE DARK SKIES OF THE DUST AND THEN PLANTS DON'T GROW AFTER AWHILE.
There are climate effects from even small volcanic eruptions, so certainly one of that scale, you would expect some climate effects. Transportation is highly affected, right? You can't fly planes through ash. So, yeah! It's something that would have profound effects.
IS THERE ANYTHING ABOUT THE GAS RELEASES THAT YOU STUDY IN YELLOWSTONE THAT WOULD GIVE YOU A SUDDEN RED FLAG WARNING THAT SOMETHING ELSE MIGHT BE OCCURRING?
When we look at the helium isotopes, if we saw large changes over time, we would certainly be interested. We have not, but we look for those things. If we saw an area really heating up and losing its water markedly and you started seeing higher temperature gases coming out of the ground — like sulphur dioxide, which we see in volcanoes, but we don't see it in geothermal areas like Yellowstone. Sure, there's lots of things we can do in terms of gas chemistry to monitor the system.
Yellowstone is a little tricky to monitor like a normal volcano just because it's so big and so diverse. It's hard to set up a monitoring program that will be very effective without being just exhorbitantly expensive.
WHAT IS YOUR OWN THOUGHT ABOUT WHETHER OR NOT — LET'S SAY IN THE 21ST CENTURY— THERE'S GOING TO BE ANY LARGE ERUPTION OUT OF YELLOWSTONE?
I think it's extremely unlikely. I don't expect Yellowstone to erupt in the 21st Century. It has not erupted for 70,000 years. I think there will be more swarms. There's going to be more uplift. There's going to be more activity. There could be hypothermal explosions. We've had a lot more of those in the last 10,000 years — more than we've had volcanic eruptions. There's a lot to watch at Yellowstone, but I don't expect it to erupt (this century) — not a volcanic eruption.”