There's always a lot of shaking, rattling, and occasional rolling going on in Yellowstone National Park. Keeping track of it is the Yellowstone Volcano Observatory, one of five such observatories under the purview of the U.S. Geological Survey. It keeps real-time tabs on volcanic, hydrothermal and earthquake activity in the Yellowstone Plateau volcanic field.  

Traveler’s Lynn Riddick speaks with the scientist-in-charge of the observatory, Michael Poland, Ph.D. From his home in Vancouver, Washington, Poland gives us a glimpse into the latest monitoring systems in Yellowstone National Park and the park’s recent geologic activity. 

Transcript:

SPEAKERS

Lynn Riddick, Dr. Michael Poland

Lynn Riddick  00:00

Created in 2001, the Yellowstone Volcano Observatory is a unique virtual partnership. It's composed of scientists from nine different federal and state agencies, as well as university-based researchers with extensive knowledge and experience in volcanology and geology. Member agencies monitor, measure, analyze and report data collected from the vast outdoor laboratory that is the Yellowstone plateau. And their work increases our understanding of the forces that feed this immense hydrothermal system and whether hazardous activity might be at hand.

I'm Lynn Riddick, speaking with Dr. Mike Poland, who is a research geophysicist and the scientist-in-charge of the Yellowstone Volcano Observatory. Hi, Mike, welcome to the Traveler.

Dr. Michael Poland  00:47

Thanks. Hi, how are you doing?

Lynn Riddick  00:48

I'm doing good. So I want to talk about the Yellowstone Volcano Observatory, though YVO for short, it's a consortium of state, federal, and academic institutions. Tell me who some of these players are and what the YVO was tasked with.

Dr. Michael Poland  01:05

Sure. So YVO started in 2001 as a joint venture between the U.S. Geological Survey, Yellowstone National Park, and the University of Utah. University of Utah does a lot of the seismic monitoring in the region, and then of course the national park has a huge interest in all of the thermal features and curating those and also studying them, and then the Geologic Survey was doing a lot of the geologic mapping and, and studying past eruptive activity.

And it was expanded in 2012-2013 timeframe to include the state geologic surveys in Wyoming, Idaho and Montana, as well as the University of Wyoming and also a group called UNAVCO, which operates deformation-monitoring stations throughout the US, basically looking at how the ground moves. And then I'm really happy to announce actually that we just expanded it once more, just weeks ago here in 2020. We added Montana State University, which does a lot of research into the geology of Yellowstone and also how these thermal bacteria in a lot of the hot springs survive and what they might mean for the origin of life. So it's now a nine-member institution. 

Lynn Riddick  02:15

A lot of expertise there. Do you know how many total people are involved then in these nine organizations?

Dr. Michael Poland  02:21

Oh, geez, I'm not sure I could count it. Typically, when we have meetings, there are somewhere between, you know, say 30-40 people that are kind of the regulars. But there are an awful lot more people at each institution that may not be regular attendees at our virtual meetings and telecoms, and so forth, but they contribute to the science either by maintaining instruments locating earthquakes, or by some of the research they do. So it's, it's probably when you look at all the people that contribute well over 100 folks that contribute to YVO in some way.

Lynn Riddick  02:53

Now, are each of these YPO entities responsible for monitoring different things and do they collaborate on monitoring this same type of data. 

Dr. Michael Poland  03:02

Well, the answer to both questions is yes. The University of Utah, for example, has the responsibility for locating earthquakes in the Yellowstone region. And UNAVCO, which is this group, it's an academic nonprofit in Boulder, Colorado, has the responsibility for maintaining the GPS stations that we use for monitoring ground deformation. 

But we all talk, we all use the data together. So it's not like Utah is the only group that uses the seismic data or UNAVCO is the only group that uses the deformation data, we all sort of look at the data together to try to understand monitoring-wise, you know, what's happening. If there's an earthquake swarm, what it might be related to, and then we also do research together. So you'll often see scientists from the USGS collaborating with people from the University of Utah, University of Wyoming, Wyoming state survey, whatever to better understand how Yellowstone works.

Lynn Riddick  03:55

Now, there are five total volcano observatories in the US. They Include California, Cascades, Alaska, and Hawaii. And of course, Yellowstone. You've worked for Cascades and Hawaii and now Yellowstone. What are some of the major differences among these vast areas of volcanic activity?

Dr. Michael Poland  04:14

Well, each observatory sort of has its own style. One of the things that makes YVO different is that we don't have a physical facility. There's no building that says Yellowstone Volcano Observatory, whereas there is a building for CALVO, CVO, HVO and AVO. And YVO is also institutionally broader. We have these nine institutions that make up the observatory, whereas the collaborations are more limited in the other observatories.

For example, CVO works with the University of Washington, and AVO works with the state survey in Alaska and the University of Alaska. So there are partnerships, but I think YVO takes it to an extreme in terms of the broadness of the partnerships, and the fact that we're sort of a virtual observatory. 

And there's also the style of activity we monitor. HVO, I was I was based at HVO for 10 years. And there was this emphasis that, you know, Kilauea at the time was erupting constantly and Mauna Loa, there's always a threat of eruption. Really keeping track of what was happening and trying to do the science at the same time you were monitoring ongoing eruptive activity. 

And in the Cascades, you know, eruptive activity sort of happens, you know, kind of creep up on you quickly. The 2004 to 2008 eruption of Mount St. Helens only had a week's worth of warning before it really started to go. So there's a vigilance aspect. And we have a lot of that at Yellowstone, which is sort of neat. We have the vigilance aspects, of course, we're looking for all kinds of activity that might be happening in the Yellowstone region. But there's also that dynamic nature of Yellowstone where things are always changing.

I go there pretty frequently and it's never the same experience twice. Not only because of the seasons, but because geysers may be entering different phases of activity, or you may see you know, thermal features change, shape or change their characteristics. And that's something I really enjoy about the job is the fact that it's always changing. There's always something to sort of learn about.

Lynn Riddick  06:16

What are the broad categories of measurement and monitoring that you do?

Dr. Michael Poland  06:21

Well, the backbone of any monitoring system at any volcano worldwide is really seismic monitoring. As magma moves beneath the surface, it breaks rock and that gives you earthquakes. And there are subtler types of earthquakes as well, different frequencies we can see that might be related to magma moving or fluids, like gas and water moving in the subsurface. So seismic monitoring is really the backbone and it's really quite good at Yellowstone.

The University of Utah has been doing this for decades. And they've got a very comprehensive net of seismometers that are quite advanced. They're modern digital instruments that are capable of recording quite small signals. But geodetic data - this is deformation data - is equally important. And the advent of GPS, say a few decades ago, really made it possible to monitor deformation in a continuous way.

So there are a couple of dozen continuous GPS stations in the Yellowstone region. I think there's about 15 of them located in the park. And they're constantly reporting back on how the ground is moving, whether it's moving up or down. And in Yellowstone that changes, the ground is always going either up or down. And it changes from year to year.

And then outside of that, monitoring geyser activity monitoring the gases that are released, the chemistry of the gases, the chemistry of the water, that's something that doesn't really happen on a continuous basis, but is often done by campaigns where we will go and collect water, collect gases from different thermal areas, and then take them back to the lab and analyze them. And we have some continuous sensors to in the lakes and streams and rivers that drain the Yellowstone area. So the monitoring is pretty comprehensive. And Yellowstone actually is among the best-monitored volcanoes anywhere in the world.

Lynn Riddick  08:08

That's interesting. And I wanted to ask you a little bit more about the GPS and the radar that you use in the monitoring. How do they work exactly?

Dr. Michael Poland  08:17

Well, it's all based on satellite technology. The GPS method uses an antenna that typically is cemented in place. And that antenna is receiving signals from orbiting satellites. And it uses those signals to calculate its position. Just like your phone or the GPS you might have in your car. But we use a slightly different form of the signal that allows us to get millimeter level accuracy. 

So we're seeing tiny, tiny changes in how the ground moves. And typically we see that the ground moves up and down at a rate of a couple of centimeters a year, maybe an inch a year or so. So we're able to resolve that thanks to GPS. But we're only getting the measurements where we have GPS equipment positioned on the ground. 

The neat technique of this radar technology, which we call INSAR for short, stands for interferometric synthetic aperture radar. That's like having a deformation camera in space. We use a couple of radar images, acquired at two different times of the same place on Earth, to detect how the ground has moved from time one to time two. It doesn't work in really heavily vegetated areas or where there's a lot of snow and ice. So in Yellowstone is not so useful during winter months. But during the summer months, it works actually quite well. And we can see how the entire park moves between the time of these two radar acquisitions without even actually being there. And that's really revolutionized the way we can see deformation in Yellowstone and many other volcanoes worldwide.

Lynn Riddick  09:49

That's really amazing.

Dr. Michael Poland  09:51

Yeah, the technology is, I mean, it's staggering to think that you know, just 20 years ago, this didn't really exist as a monitoring tool and now, we're doing this very routinely. And more and more satellites are going up all the time. It makes me think sometimes I wonder what 20 years from now we'll be talking about in terms of these, these kind of major advances. I can't even imagine what we might be able to detect 20 years from now, that isn't even really a thought right now.

Lynn Riddick  10:20

Yeah, that would be interesting to see for sure. You mentioned 15 different GPS monitoring stations in the park. Where are they located? And I was curious to know if visitors can see these stations, and if so, are there educational programs to explain to visitors with they are?

Dr. Michael Poland  10:38

Well, we try to keep them sort of out of sight. It's Yellowstone, it's a place that really, you don't want to have too much of an impact. You don't want to have monitoring equipment sitting right on top of Old Faithful, you know. We're stewards of the land and of the traditions and the culture and the natural resources. So we try not to impact the landscape that much. 

So generally, these are located in side roads, service areas, things like that, which are sort of off limits to the public, but are still kind of developed areas. So we're not putting them in, in places that are really sensitive. There's a few spots where, of course, we need information from areas that might be, you know, rather far from any developed area. So we do have to put instruments out there, but we try to minimize the footprint and minimize the impact.

But there is a pretty good visitor display at the Canyon Visitor Center. It includes some GPS equipment, and also some of these radar images that show the ground moving up and down. And so if visitors are really interested in seeing what one of these setups might look like, then I'd encourage them to check out the Canyon Visitor Center, and there they can they can see some of the equipment that we use.

Lynn Riddick  11:51

When you talk about uplift and subsidence, what exactly is uplifted and is there a typical size of an uplift area in Yellowstone? What areas have the most activity?

Dr. Michael Poland  12:03

Well, it can be quite broad. So the caldera uplift, it basically spans the caldera. So we're talking, you know, dozens of kilometers across. The Norris uplift anomaly tends to be a bit more focused. And it's gotten a little more focused with time, which suggests that there are different depths that are active. And so what we saw in the late 1990s, early 2000s, was something that was pretty deep, many kilometers, many miles deep. And that suggested to us that there was a magmatic intrusion. And that happens from time to time in various places in the parks.

The magma was injected, deep beneath the Norris area. The more localized signals that we've seen in the 2010 timeframe, the 2010s, that the decade we just finished, seemed to indicate shallower sources of deformation. And we attribute that to gases and water that might have come off of the magma that was injected back in the ‘90s. And it gradually migrated up towards the surface. 

And the reason we think it's gas and water is because just how dynamic it was. So in 2013, we started seeing uplift rates of many centimeters per year. In fact, they were the fastest uplift rates or subsidence rates we'd ever seen at Yellowstone. And then in March of 2014, there was a magnitude 4.9, I believe, earthquake in the Norris area. And the next day, the ground started to subside. So it was as almost if there was fluid accumulating behind, almost like a valve of some sort. And then that earthquake was the valve breaking, and the fluid was able to drain, and the ground subsided at the same rate that had risen in the months before.

So there's a lot of dynamic activity happening at Norris that we believe is related to water that's moving around in the subsurface. And, you know, Norris is one of the most active geyser basins in the park. So it's not really a surprise that there will be a lot of water moving around in the subsurface.

Lynn Riddick  13:53

I want to talk about earthquakes in a little bit here, but first, can you describe the volcano explosivity index and what rating do scientists give the initial three volcano events at Yellowstone?

Dr. Michael Poland  14:08

Yeah, sure. So VEI - volcano explosivity index - is sort of the Richter scale for eruptions. Each VEI number is 10 times bigger or smaller than the one before or after. So a VEI five is 10 times bigger than a VEI four, so it's a logarithmic scale.

So a VEI zero eruption basically is not explosive. You can actually have negative numbers just like you can have negative earthquake magnitudes. This just means it's an extremely small, explosive event like a bubble bursting. Mount St. Helens 1980, which is an eruption that most people are familiar with, was a VEI Five. Pinatubo 1991,was pushing at a VEI six. That's one of the largest eruptions of the 20th century.

The two really big Yellowstone explosions of the past 2 million years, there's one 2.1 million years ago and one 631,000 years ago, those were VEI eight. So they were, you know, hundred times or 1,000 times bigger than the 1980 Mount St. Helens eruption. And it's, it's calculated based on the volume that comes out in these eruptions. So basically 1,000 times more volume came out during these big Yellowstone eruptions, then came out of Mount St. Helens in 1980. And there was a third large Yellowstone explosion that occurred about 1.3 million years ago, that was a VEI seven. So Yellowstone has this history of very large explosive eruptions, and they sort of tipped the scale at this highest level of the explosivity index.

Lynn Riddick  15:47

And when you say the volume released, are you referring to ash and lava and rock or?

Dr. Michael Poland  15:54

Yeah, sort of all of the above, in these big explosions, there's not a whole lot of lava that comes out. It's really all ash. Really close to the source that ash compacts very quickly, it sort of fuses and welds itself into very dense rock.

So the ash deposits that are in and around Yellowstone are absolutely solid rock. But then there's an ash layer that extends out quite far you can find many states away from Yellowstone that also contributes. So you sort of add all of that up in order to find just how much came out of the volcano and that helps you define what the VEI of a certain eruption was.

Lynn Riddick  16:32

Now I understand all park entrances to Yellowstone are now open, although there are still closures with lodging and visitor facilities. What if any fieldwork had to be halted when the park was closed? Did you lose any data and if so, is that something you can catch up with?

Dr. Michael Poland  16:48

Well, we certainly lost some time. You know, we have a very good relationship with the park. They're of course members of the Volcano Observatory, and we're always working with the park to make sure that our field operations sort of jibe with their operations, and we're trying to stay out of their way and make sure we're doing a responsible job with the monitoring, while also being responsible stewards of America's first national park.

And so typically we have a field campaign that's usually in early May, late April, right as the snow's starting to melt, where we'll install some temporary GPS stations to kind of ‘densify’ the monitoring network and do maintenance on some of the stations that might have gone down over the winter, because those the winters in Yellowstone are pretty unforgiving. And we always lose some equipment here and there. 

And then we talked with a park and they asked that we you know, sort of hold back a little bit until the park was open a bit more, and there was nothing that was critical. You know, they definitely agreed that if there was any seismic station that was critical that went down, that we would get in there and repair it. But that wasn't necessary. Fortunately, the seismic network in the GPS network came through looking great after the winter.

So instead we started work in very late May and early June. We got in and we repaired some of the temperature-monitoring equipment in the Norris area that measures geyser activity there. Some of the batteries had died there. And we also deployed these GPS stations, these temporary stations that we put out every summer. So we lost a few weeks of data. But that's not a, it won't really compromise us too much. And in fact, we were a lot more efficient because there was a lot less snow in late May than there usually is.

Lynn Riddick  18:32

Volcanic activity, hydrothermal features, and earthquakes are very much connected in Yellowstone, as you know. Do you think it's safe to say that earthquake activity is much lesser known by the general public?

Dr. Michael Poland  18:46

I think that is safe. You know, the Yellowstone has this reputation thanks to various documentaries and docu-drama movies and so forth, that it's this big volcano. That, it's kind of the boogeyman. It's gonna kill us all. Which is pretty undeserved because most of the magma chamber beneath Yellowstone is solid right now. There's no sign at all that there's any kind of eruption much less than explosive eruption sort of on the horizon.

Earthquakes are a different story. Yellowstone sits in a really active part of Western North America. There are magnitude 7 earthquakes that happen there frequently in terms of geologic time. The most recent was in 1959. And it resulted in the deaths of over two-dozen people when part of the Madison Canyon, a mountain in the Madison Canyon, collapsed and created Quake Lake, a lake that you can still go visit today.

So the earthquake hazard in the Yellowstone region is pretty high, as it is through much of the Western US and I think we've had an example of this over this past summer where we've seen earthquakes in Idaho, there was a magnitude 6.5, and then there was a magnitude 5.7 I believe near Salt Lake City. The Western US is an incredibly dynamic and incredibly active place, and Yellowstone is no exception. And really on human timescales, we're likely to see earthquake activity far sooner than we're going to see any volcanic activity.

Lynn Riddick  20:11

Interesting. Now, I understand Yellowstone averages 1,500 to 2,000 earthquake events a year, and May 2020 seems to have been a very active earthquake month with 288. What is the size of the typical earthquake here?

Dr. Michael Poland  20:28

Well, the earthquakes typically you don't feel. They're a magnitude 1 or 2, less than 1. So they’re very small. There are occasionally felt events in the magnitude 3 or 4 range, there's typically a few a year. And occasionally you'll have a swarm of events that's large enough to have several felt earthquakes. A good example of that was in the latter part of 2017. Between June and September of 2017 we had a swarm of earthquakes that included 2,400 located events, and there were a few of that were in the magnitude 4 and 3 range that were felt. 

And that was only the second largest swarm. The biggest swarm was back in 1985. There were more events that went through a longer period of time. And this is sort of typical of Yellowstone. It's a very ‘swarmy’ place. We see earthquake swarms all the time, typically every month has at least a few earthquake swarms and May had four, one of which was right at the end of the month. And I think there were about 100 events in that late-May swarm. That's sort of typical for Yellowstone. That's kind of how it works. But the vast majority of these are not felt.

Lynn Riddick  21:34

Have you ever felt any of these larger ones yourself?

Dr. Michael Poland  21:38

Not at Yellowstone. I've never been there when there's been a quake that was large enough to feel. I was actually in Yellowstone when this magnitude 3.1 hit. That was part of the late-May swarm in 2020. And I didn't feel that. Of course, I was staying up in the northern part of the park and that was happening in the Norris area. So, I wasn't that far away. I was 20 miles or so but didn't feel thing. I mean I felt earthquakes many other places but haven't at Yellowstone at this point.

Lynn Riddick  22:06

I'm talking today with Dr. Michael Poland of the Yellowstone Volcano Observatory. We're going to take a short break but we'll be right back.

I'm Lynn Riddick, back again with Dr. Michael Poland who is scientist-in-charge of the Yellowstone Volcano Observatory. What got you interested in studying volcanoes? Tell me about your background and how you got such a cool job.

Dr. Michael Poland  22:34

It is a cool job. I guess I have to attribute it to Mount St. Helens. I was a kid when St. Helens erupted in the 1980s, and I remember watching the news and just being fascinated by it, by this you know, the, the scale of what happened in 1980 was just unprecedented. And through school, I remember getting the Scholastic Book readers. You know, people in my generation might remember those, where you could order books and there were always volcano books about Mount St. Helens.

And I grew up in Northern California. So my dad and I would go camping at places like Mount Lassen and Mount Shasta. So it was sort of always in the background. And when I got to college and decided I'd take a geology class just for kicks, it really took hold. And I got lucky I had great mentors, great professors, great guides throughout my education that encouraged me to keep exploring, and that took me to really interesting places.

And eventually, I was lucky enough to get a job first with the Cascades Volcano Observatory in the early 2000s. And I got to experience the start of the Mount St. Helens’ eruption from 2004 - 2008. I was there for the first several months of that eruption. And it was inspiring because I was working alongside people that had been there in the 1980s. And to see the way they worked, I found it made a deep impact on me to, a deep impression on me into how scientists work in a team during these crises to try to understand what's going on and communicate that information to the public.

And then I moved to Hawaii in 2005, and I was on the staff of the Hawaiian Volcano Observatory for 10 years. And there, I dealt with a number of eruptive crises. And I got to put some of what I learned at Mount St. Helens into practice. It was a wonderful scientific opportunity, because you're right there on the volcano. You can walk right up to the activity and design experiments and test ideas. It's just a wonderland.

And I felt like my job mattered because some of the eruptions there did threaten populated areas. And I really felt like the things that I did had real meaning to people that lived on the volcano. I participated remotely and I also went back a couple of times in the 2018 eruption, which of course was devastating to the area. That was heartbreaking to see as somebody that lived there. Seven-hundred homes were destroyed in 2018 by that big lava flow, and it changed the volcano just forever. But that's part of what Kilauea is. It's dynamic.

But by then I had moved back to the Cascades Observatory where I was working again on places like Mount St. Helens. And then in 2017, I was able to take the position with the Yellowstone Observatory, which I just feel very lucky to have. It's brought me the opportunity to work with all kinds of great scientists from so many different institutions in a place that's, I mean, it's Yellowstone, right? And you don't have to work very hard to be interested in that.

And it's, it's this ever-changing place that is very cool to study and explore. There's always something new there, there's always something new to be learned. So I feel really fortunate to work with the folks I do into that have had those experiences and to have it all leading me to be able to work at Yellowstone has been wonderful.

Lynn Riddick  25:58

Now is there a volcano that you find especially fascinating?

Dr. Michael Poland  26:02

Whoo. Well, I have sort of my favorite volcano that I like to hang out in. When I'm not hanging out in Yellowstone. I love this volcano in Northern California that not many people will have heard of named Medicine Lake. There's a national monument right on the flank of it, Lava Beds National Monument with amazing caves to explore. It's stunning.

But Medicine Lake itself, it's not a pointy volcano like a lot of the Cascades. It's a broader volcano. But it has obsidian flows and cinder cones and lava tubes. It has a small caldera at the top with a small lake in it. It has all kinds of places that you can explore. It's a fantastic amazing place and not that many people know about it. So it's relatively calm. It's in the northeastern corner of California.

There's even a lot of history in the area, Native American history and more recent history that is really interesting to learn about. So, I love being in Medicine Lake, and that's where I did some of my very first research because Medicine Lake is sinking. It's sinking at a rate of about a centimeter per year. And it has been for at least decades, probably for millennia. And so some of my first research was trying to understand why is Medicine Lake sinking? And it's not a, there's not a straightforward answer to that.

So I've always been attracted to this sort of question of one, we can measure this and it's amazing we can measure that this big volcano is sinking by about a centimeter a year, and then we can go explore what might the causes of this of the sinking be so I'm, I always like going back to Medicine Lake for personal, professional, and just fun reasons.

Lynn Riddick  27:42

The Yellowstone Volcano Observatory categorizes volcanic activity threat levels as high, moderate and low slash very low. We are now in a low slash very low stage. Now what thresholds have to be met before the threat levels are increased?

Dr. Michael Poland  28:00

Well, the threat levels are based on not current activity, but on the potential for some current activity. So the USGS, starting in 2005, and then revising it again in 2018, looked at all of the volcanoes in the US and assigned a threat level that's based on eruptive history, basically the size of the eruptions, the areas that they impacted, and so forth. And also the threat posed to people. How many people live nearby, how many airplanes fly over that might be affected by ash plumes, and the like?

And that classification resulted in kind of identifying the volcanoes that were the most threatening to people based on the impact they would have and their frequency and style of eruption and the No. 1 most threatening volcano on that list was Kilauea in Hawaii. And of course, it did destroy 700 homes in 2018.

Most of the volcanoes on the list were these pointy strata volcanoes like Mount St. Helens, Mount Rainier, Mount Redoubt in Alaska, and Yellowstone ended up No. 21 on the list. And that's because it does have this, even though it hasn't erupted in 70,000 years, and that was a lava flow. And the last huge explosion was 631,000 years ago. It can obviously impact a very large area. And there is a very large seasonal population. There's 4 million people that visit Yellowstone every year.

So the potential to impact people is high, even from a lava flow that would be relatively easy to get out of the way of but it certainly could have impacts. We also have a classification scheme for each volcano on basically its activity levels. And you could easily think of it as being sort of green, yellow, orange and red. And as volcanoes progress in their activity, they will climb that scale to where a red volcano is having a hazardous eruption. An orange volcano might be having an eruption that's not particularly hazardous; yellow might be some unrest, and green means the volcano’s at background. Yellowstone has always been at the green level. That's not to say it's not active. It just means that its background has never really been exceeded, and the background of Yellowstone is ground’s always moving, geysers are erupting, there's always lots of earthquakes. So background of Yellowstone happens to be, you know, pretty active.

Lynn Riddick  30:23

I understand a report just released by a team of scientists from the University of Leister, the British Geological Survey, and the University of California Santa Cruz suggests that two additional eruptions occurred long before the three major eruptions that we associate with Yellowstone going back 2.1 million years. The study also suggested that Steamboat Geyser has been in significant decline for some time. What are your thoughts on these findings? And is this an intriguing area for further investigation?

Dr. Michael Poland  30:54

Well, one of the things I think is very cool about that study is these scientists went to these ash layers that are preserved in Idaho. And there's actually, they're all over the place in Idaho because the Yellowstone system sort of traversed that area as the North American tectonic plate moved over this relatively stationary hotspot, a bit like, you know, moving the plate over a blowtorch. 

And so there's this trail of volcanic activity is preserved in Idaho, and you can see ash beds everywhere. But they're hard to correlate, you know? Does the ash bed on one side of the valley match the ash bed on the other? It's very difficult thing to figure out. And this, this team of scientists from various institutions, used a number of different methods to correlate the ash beds from several eruptions that were thought to be separate. 

And so, smaller ones, and they found that actually, no, these weren't a number of smaller eruptions. It was two very large eruptions that happened eight, nine million years ago. And so that increased the number of very large eruptions that had been generated by the Yellowstone system.

But the other interesting implication of that is not necessarily related to Steamboat, but in relation to Yellowstone on the whole. It suggests that the time period between really huge explosions is actually lengthening. So way back when and you know, 10 million years ago, there were huge explosions happening every few hundred thousand years. Well, now we've got hundreds of thousands to millions of years between really huge explosions. And so they're suggesting that perhaps the entire Yellowstone system might be sort of petering out, might be on the decline.

And there's a number of reasons why that might be. Perhaps the plume, the hotspot that's supplying all of the heat that's melting all this rock might just be sort of losing steam. The other possibility is that the Yellowstone system is starting to get under some very thick crust, so that as the North American continent moves over this this hotspot, it's mostly been in thin crust of Nevada and Oregon, Idaho and now western Wyoming. But as you're moving into central Wyoming, the crust thickens significantly.

And you get into an area that's not as tectonically active, not as thin because of all this faulting. And it might be that Yellowstone just can't burn through the thick continental crust it's going to come into contact with, so maybe it's on the decline because it's sort of getting covered up. But it's, it's fascinating work. And I'm really impressed that the authors managed to so meticulously correlate all of these different ash beds to come up with a better, basically map of what Yellowstone has done in the past. I think that shows great potential for this kind of study to be done on other eruptions, not only of Yellowstone, but elsewhere in the world,

Lynn Riddick  33:43

The American Recovery and Reinvestment Act of 2009, the so-called stimulus bill, gave the five volcano observatories and additional $12.2 million to upgrade monitoring systems. What was missing in the monitoring and research systems prior to this funding and what gaps remain regarding what you would still like to do?

Dr. Michael Poland  34:04

Well, there were a lot of pieces of equipment that we just couldn't get ahold of, because they were rather expensive. And it's, it's difficult when you're in the government position to save money. There are ways to sort of bank money to buy bigger pieces of equipment down the road, but it's difficult to do. So one of the things that we're able to do with this, the stimulus funding, was to buy expensive pieces of equipment that normally would have been kind of out of reach.

And an example that I used is gravity equipment. We tend to think of gravity as a constant, right? We learned this in high school that gravitational acceleration is 9.8 meters per second squared, almost forgot that. And it doesn't vary. It's constant everywhere. And it's not quite true. It actually does vary, and it depends on what's beneath you. So if there is magma intruding beneath you, the gravity will actually increase.

And do using the stimulus funding, I was in Hawaii at the time, we were able to purchase some gravity measuring equipment that we used at Kilauea and we were able to see gravity increases that suggested magma was accumulating, and the measurements we got there were more sensitive than any other technique. And so it's sort of opened a whole new level of monitoring that we wouldn't have had access to before.

We were also able to get more GPS equipment, more seismic equipment, and do upgrades. One of the things that we hear a lot of is sort of infrastructure upgrades are needed across the country, and the volcano monitoring systems are no different. After Mount St. Helens erupted in 1980, we invested quite a lot of time and effort in deploying monitoring stations throughout the region, Yellowstone, the Cascades and California, Alaska. But back in 1980, digital radio telemetry, digital instrumentation was not the norm. And so a lot of our monitoring stations were suffering from frankly being old.

So having this influx of funding allowed us to modernize, we went to digital telemetry, we moved to digital stations so that the seismic data didn't have to be digitized by this complex array of computers once it got back to the lab. When I was in the Hawaiian Volcano Observatory, we had an entire room that was nothing but computers that were taking analog seismic signals, and digitizing them so that we can then use modern computers to analyze the data. And after 2009, and all the upgrades, that entire room went away, because suddenly we didn't need all these computers that were basically charged with digitizing seismic signals.

So it was really about modernization, and advancing to a next level of monitoring so we could employ new technologies, employ new equipment, and also deploy new equipment like GPS receivers in places that we didn't have them before. 

Lynn Riddick  36:52

What's on the top of your must have list?

Dr. Michael Poland  36:56

Well, I really think that we should have more gas monitoring. Gas monitoring Yellowstone is really hard because anyone that's been to Yellowstone can tell you, you can't sort of go around the corner without coming across the thermal area. 

Most volcanoes, the gas comes out the top, you know, at Kilauea the gas comes out of wherever the eruption is, or from the summit area so you can really focus your monitoring. Same thing at Mount St. Helens or Mount Rainier or wherever the gas is coming out of the top of the volcano for the most part.

Where is the top of the volcano at Yellowstone? There isn't one. There's gas coming out of the entire park, just about. And so it's really hard to monitor gases at Yellowstone, you would have to have continuous stations, which are still kind of a new technological development. Continuous gas monitoring has not been around that long. You would need to have them all over the place. And that's just not logistically viable. It's not financially viable.

So there's a whole lot of problems with that. So I'd really like to know more about how gas is coming out of Yellowstone varies over time on a much more systematic way. We're measuring earthquake activity and ground deformation and river systems on a minute-by-minute basis, second by second in some cases. We're not measuring gases that way. 

So it's difficult to know whether there's a change in gas emissions when there's an earthquake swarm, or whether the style of degassing changes when the ground goes up vs. going down. So that's something I'd like to do more of, and there are some tantalizing ways that we might explore this with some continuous equipment that is becoming a little bit more cost effective.

But also with aerial surveys, aerial surveys, thanks to unoccupied aerial vehicles, are becoming easier to do. So it might be that one day, we can do gas monitoring just by putting drones up and measuring gases. So I think the future is pretty exciting for that sort of thing. And it's something I think we desperately need at Yellowstone.

Lynn Riddick  38:55

Mike, when you tell people what you do for a living, what's a common response?

Dr. Michael Poland  39:00

I often get the Vulcan salute. It's funny if I want to engage people in conversation, I'll say I'm a volcanologist. And usually then there's a question about,’ Oh, well, you know, what about Krakatoa erupted or I heard Mount St. Helens is having activity’ or inevitably there's sort of a question about Yellowstone because most people have heard that there's a huge volcano under Yellowstone that will one day kill us all.

If I don't want to talk to people, I'll tell them I'm a geologist and that seems to be almost a conversation ender. ‘Oh, rocks. That's, that's exciting.’ It is, it is to me but I, I really enjoy chatting with people about volcanoes. 

I love being in the park in Yellowstone. I love it when people stop me when they see me at the side of the road taking a gravity measurement. I'm in my, you know, orange safety vest that says USGS on it, and they ask me what I'm doing. And I really enjoy talking to people about the activity at Yellowstone, the kind of measurements we collect, the things that we learn. It's not something to be afraid of by any means. And I think most people get that. It's utterly fascinating. And, and I love sharing that sort of information with people that drop by when I'm working in the park.

Lynn Riddick  40:11

Now, what you alluded to about misconceptions, you know, Yellowstone is due for a big eruption. And it's funny because I heard it just yesterday, myself when I was telling a friend, I was working on this podcast. Is this a myth we're ever going to shake?

Dr. Michael Poland  40:26

Ahhh. I don't think so, try as we might. It's just too attractive a myth. You know, we hear oftentimes, oh, well, Yellowstone's overdue. Well, no, it's not. That's not the way volcanoes work. And even if it was, the math doesn't add up for it to be overdue.

Just like Yellowstone is going to explode. Well, most people don't realize that the most common form of activity in Yellowstone is a lava flow. There have been dozens of lava flows since the last huge Yellowstone explosion, and even the last one of those happened 70,000 years ago. 70,000 years ago. Mount St. Helens didn't even exist as a mountain. And that was the last time any magma made it to the surface at Yellowstone.

So I think it's, it's an attractive myth. And it generates headlines and it's something you click on right. I mean, I do the same thing when I see headlines, you know, ‘Yellowstone this or that,’ I click on it because it's interesting. It's captivating. 

But the thing I think is important to understand is that it for Yellowstone, we don't need the hype. Yellowstone is amazing. You can't go there and not be impressed by the geyser activity and the wildlife and the scenic and wild nature of the place. It's spectacular enough on its own. It doesn't need to be made any more spectacular. And that goes for the science too.

The ground in Yellowstone goes up and down by centimeters every year and it changes all the time. Norris was going up and then it was going down and it's going up. That's amazing. And I think that's, that's plenty interesting on its own. It doesn't mean sort of the false pretense of, ‘Oh, yes, and that means it's going to erupt,’ which, you know, it's most likely not.

Lynn Riddick  42:12

Another misconception is that the magma chamber is growing. What can you tell us about the magma reservoir?

Dr. Michael Poland  42:19

Well, the magma reservoir beneath Yellowstone is huge. It has to be big in order to feed the massive eruptions that have occurred there. One of the things we can do to investigate the magma chamber is to look at seismic waves that have passed through the reservoir.

So you've sort of set up seismometers all over Yellowstone, and there may be as an earthquake that happens somewhere else on Earth, Kamchatka, Vanuatu, wherever. And the seismic waves are recorded in Yellowstone, but they have to pass through the Yellowstone magma chamber before making it to the surface. And by looking at earthquakes that happen around the world, pretty good sized ones, and also the pattern of recordings you see in Yellowstone, you can sort of map out the characteristics of the magma chamber.

And what seismologists from the University of Utah found is that there's actually two magma bodies. The first is about three to 15 miles deep or so and extends down to that lower level. And then below that, there's another one that goes, you know, 15 to 30 or 40 miles deep, but they're both mostly solid, they're hot, they're maybe even a little bit mushy in places, but the amount of melt in that upper one is only something like 5 to 15%, and then lower ones about 2 to 5%.

And this is known because the speed of the seismic waves passing through that zone of partial melt is going to be controlled by the temperature. If it's very hot than the waves slow down and if it’s cooler, then the waves speed up. So there's a lot known about the magma system from these seismic experiments, and there's actually a new experiment that hopefully will happen this summer well, where there will be some local earthquakes that are generated.

There's some, a truck that can basically vibrate the ground at frequencies that humans really can't feel, but that are really excellent for imaging the subsurface. And so this, this truck is going to be moving around the area, sort of vibrating the ground at these very low frequencies, bouncing seismic waves off the top of the magma chamber. And that should give us sort of a map of what the top of the magma chamber looks like. It's going to be unprecedented if it if it all comes together.

Lynn Riddick  44:34

And you hope that that's going to happen this summer.

Dr. Michael Poland  44:37

Yeah, so the plan had been to do it this summer. And I think the plan still is to do that this summer. But obviously, everyone's plans have changed around the world. So I'm sort of cautiously optimistic. I think we need to understand that there's a bigger picture here than just, you know, our little Yellowstone experiments.

Lynn Riddick  44:58

Well, since monitoring began in the ‘70s, what are the most revealing trends about volcanic disturbance in Yellowstone? And how do they compare with Yellowstone lore?

Dr. Michael Poland  45:09

Well, I think the lore of Yellowstone is, if we're thinking about history, is quite neat, because going back to some of the expeditions of the 1860s and 1870s, there were stories of early explorers experiencing earthquakes in Yellowstone. It was known to be a really active place back then.

So what we're seeing now with this well-instrumented ability to see all of these small earthquakes, sort of verifies the accounts of these early explorers, that the kinds of things that they were experiencing just camping on the north shore of Yellowstone Lake in 1870, well, we see what that was, what caused that, it was the earthquake activity that we see today.

So I really feel like the monitoring that we've been able to do has opened the doors, and one of the neat things about science in general, is that even when you answer a question, how many earthquakes are there in Yellowstone, for example, it tends to open the door to two more questions, at least, that you didn't even know were out there.

Okay, so why are there so many earthquakes in Yellowstone? Well, it turns out, there's all kinds of faults in the Yellowstone area. And there's lots of water moving around in the subsurface and that opens the door to even more questions. And so the level of monitoring we have at Yellowstone, the comprehensive nature of the seismic monitoring and the ground deformation monitoring, the explorations we've done with these thermal areas, just opens the door to explorations that you couldn't do in other places, because you just didn't know it much as much. You didn't know the questions to ask in some places, and then Yellowstone, we're starting to ask questions that are really detailed, that are really built on these decades of monitoring and science that have happened and that's, that's exciting when you're really starting to dig down in a place like that, it's an exciting time to, to try to understand even more about these systems, how they work and what they might do in the future.

Lynn Riddick  47:08

Your observatory offers a weekly column called the Yellowstone Caldera Chronicles, you also offer a volcano notification service that people can subscribe to, and even customize their information to the five particular volcano observatories. Any idea of how many subscribers you have? And would you say there's a growing interest in volcanology?

Dr. Michael Poland  47:30

You know, offhand, I don't know how many subscribers there are. I hope that that's growing because the notification service, it was meant to be a parallel to the earthquake notification service where you can get notification of strong earthquakes that happened anywhere in the US or the world or certain regions.

And we wanted to supply something similar, where anytime there is an update about any volcano in the US, you can subscribe to get that automatically by email, whether it's monthly updates for Yellowstone or the change in the alert level at a volcano in Alaska, or all of the above that's, that's something you can do.

Caldera Chronicles is something that I do feel there has been an increase in attention for. And I'm very pleased with that. When I was in Hawaii, we did a weekly series called Volcano Watch. And this was published in the local newspapers, carried online. And every scientist at the Hawaiian Volcano Observatory had the responsibility a few times a year to write, basically, an essay about some aspect of Hawaiian volcanoes, might be history, might be recent activity, might be the research, whatever.

I really liked that as a tool for showing people you know, here's what's going on, and here's some of the neat things that are that we're doing. We're learning. And so we brought that to Yellowstone as a means of sharing some of the cool things that are happening in Yellowstone, whether it's recent activity, or we've used it to talk about current earthquake swarms or defuse rumors that we've seen.

For example, why are there earthquakes happening in Idaho? And will they affect Yellowstone? That's something we can directly address. And we've also used the column to discuss new research and discuss history. Some of the history is amazing. And there are people that have really studied the history of some of the geyser basins and how people have interacted with geysers from when Yellowstone was sort of a very young national park. And that history I find really compelling. I find history interesting, but it's not surprising since I study the history of the Earth. 

So I've really enjoyed some of the interactions I've had with people. It's fun to see folks read those articles, and then ask questions. And that's something we try to encourage, especially on some of our social media feeds where people on Facebook or Twitter can read Caldera Chronicles and then say, ‘Oh, I have a question about something I observed, or I didn't understand this aspect of what I read’ or something like that. It's a fun way to engage people. And I love it when people ask questions because it shows that they're interested.

Lynn Riddick  50:05

Now based on one of the columns that you wrote this past October, it sounds like you'd like to retire the use of the phrase super volcanoes and instead use the more accurate caldera systems. Can you explain that?

Dr. Michael Poland  50:18

Yeah, I... I don't really like even saying the S word, so I will try to avoid saying it here. But I think that that term, it was popularized by this BBC docu-drama sort of movie 15 or 20 years ago. And it's meant to describe a volcano that has had one of these VEI 8 eruptions, one of these really huge explosions. 

I think it's really a misleading term, because that implies, to many people that that's the only way the volcano behaves. It only has these huge explosions. And that's not true. Of course, Yellowstone has many eruptions that were lava flows, and not huge explosions. I also think it's a misapplied; there are many volcanoes that have had large explosions. But they don't qualify for that super eruption categorization. And so I think it's misleading, it's misapplied.

I think it just sounds kind of silly, frankly. Whereas if you use a term like caldera system, we're talking about systems that have had large eruptions, and then they've had the ground collapse under them. So the Italian volcano Campi Flegrei, which is near Naples, that's never had a super eruption. It's had some very big explosions. But people tend to think of it as being one of these kinds of systems. And it's, it's very similar in Yellowstone, except in scale. 

So I think if we can get rid of that silly term, we'd all be a lot better off, because then we’d be not being as trite, I suppose, when we talk about the volcano. But I understand. Many of my colleagues have said, ‘Oh, yeah, we agree, you know, but, but let's face it, it's not going anywhere.’ And I admit it's, It's an uphill battle, but it's one I'm willing to fight.

Lynn Riddick  52:04

What are your final thoughts on what is happening at the YVO?

Dr. Michael Poland  52:06

You know, we did just expand to include Montana State University in the consortium. It's the newest member of YVO. And I'm really pleased about that, because Montana State is, it's the closest university to Yellowstone. They're sitting right there in Bozeman, right on the northern edge of the national park. They've been working in the Yellowstone area for a long time. They've added some expertise recently that's focused on mapping the extent of the really large explosions.

So I'm excited that there's going to be some new research into looking at the big eruptions. One of the things that they're starting to find, some of these Montana State researchers in collaboration with others, there's a professor from New Zealand who's actually been looking at Yellowstone explosions for many years. They found that they are a lot more complex than just single big explosions. And we tend to think of ‘Oh, yes, well, there was the big eruption that 2.1 million years ago, 631,000, whatever, as being big kablooeys,’ and it threw up everything all at once.

If you really drill into the deposits, you can actually identify separate events within these deposits. So for example, the big explosion 2.1 million years ago that for quite a while had been thought to be the one of the largest of the Yellowstone system eruptions, possibly eclipsed now by these ones that we've just identified in Idaho, there are actually three layers. And if you look in detail at the layers, it suggests that there might have been some pretty significant time between each of these layers being deposited in some cases, perhaps decades.

So some of these big eruptions, big explosions that we thought were single events, might actually be two or three events that could have been separated by weeks, months, years, even decades. And I think that really changes our perception of what these events actually look like. You can imagine on a human timescale, if you had an explosion that happened today, and when that happened 80 years from now, you wouldn't think of that as a single eruption, you would think of that as two completely separate eruptions, you know, there wouldn't be that many people that were alive for both of them.

And in Yellowstone, that seems to be what happened, but the geologic record has been so compacted over time that they sort of looked like they might be single events. And we're starting to tease out more of this story. This is an example of that, diving in and really identifying the questions you should be asking. The more we learn, the more we realize we need to learn.

And, and that to me is really exciting, the idea that we could dive in to these, these ash layers, and look at where they're exposed all throughout the region, and understand that they weren't single events. These were complex eruptions that might have had multiple phases with decades between them. And that's a fascinating tale of the eruptive history of Yellowstone that I hope we're able to put together with the help of these, these researchers from Montana State and elsewhere in the coming years.

Lynn Riddick  55:06

Well, Mike, I want to thank you for taking time to speak with me. The topic of Yellowstone volcanoes is always fascinating and your passion is contagious, for sure. And I look forward to more of your reports.

Dr. Michael Poland  55:16

Well, thanks very much for having me. I always love talking Yellowstone.