Inside USGS, No. 4, Robert B. Smith

Inside USGS, No. 4, Robert B. Smith


Interviewer:
Describe your area of interest in Yellowstone. Bob Smith:
My area of interest follows my background. I’ve had degrees, a PhD in geophysics and
degrees in geology and I studied mathematics and computer science. So, my areas of interest
in Yellowstone have been focused using earthquake studies, seismology, I’m a seismologist
but they move into the areas of deformation using global positioning system, they move
into the areas of understanding the dynamics and the chemistry of the system. And I integrate
these together to solve a single problem. That is I never just use seismology to attack
the problem. I rely very much on the geologic history that’s been well documented in Yellowstone.
I rely on the geochemistry that other people have done. Because we have to understand the
one big basic thing is heat. It’s a very high heat flow area because heat’s coming
off of a young and active magma reservoir. That heat leads to earthquakes. The heat leads
to deformation. The heat leads to of course heating the ground that creates the geysers,
fumaroles and hot springs. And so this is roughly six gigawatts a year that come out
of the earth from Yellowstone. Enough to electrify a modern city. That is kind of the basic,
primeval that drives and is responsible for the other components. Interviewer:
What excites you about working on Yellowstone topics? Bob Smith:
I’ve gone back now for fifty something years and I’ll be honest every year we’re discovering
something new. Either the caldera’s going up or it’s going down. We’ve had big earthquakes
we’ve had interactions of earthquakes with geysers and things. And it’s always looking,
always finding out that you’re seeing processes that are active today. Many geologists in
their careers work on rocks that are millions and millions of years old. I like work on
Yellowstone because what’s happening it’s real time, it’s today. So, it’s real time
geology and that’s what makes it exciting for me. Is to look at the processes we can
from studying Yellowstone and then apply those processes to other places in the earth where
there’s volcanoes and there’s big faults and earthquakes. But, Yellowstone truly is
a window into the earths processes. It’s really an active geologic laboratory and the
laboratory is alive. Interviewer:
How did you get hooked on earth science? Bob Smith:
I was off studying mathematics or physics at the time at Utah State University. But
as I got more and more into these topics I got more and more interested in in earth sciences.
And then in 1959 we had the occurrence of the magnitude 7.5 Hebgen Lake earthquake just
on the west side of Yellowstone. And we went up immediately as students and faculty and
I had relatives there to see this giant earthquake. Well it turns out it killed 28 people. It’s
the biggest normal faulting earthquake that’s occurred in historic times in the basin and
range. At the time I’d been changing the seismogram records at the university to help
pay for my little scholarship. And when I saw that earthquake I said wow that’s what
I want to study and that coupled back with my experience in Yellowstone, trying to understand
how all that heat was being manifest I said to myself, did the Hebgen Lake earthquake
have anything to do with this Yellowstone Volcano? And that really turned me into taking
a degree in geology a bachelors degree with studies in math and computers at Utah State.
And that moved me on into geophysics following my master’s degree and that’s where I’ve
been ever since. Interviewer:
When did you begin studying seismology in the park? Bob Smith:
Following my military career I came back with my PhD. Then I went back and started thinking
about Yellowstone again. Nothing had been done there in the way of geophysics. So, I
started installing portable seismographs all around the park different places for different
periods of time for about 2 to 3 years and then we mapped out the seismicity. We mapped
out the active faults. We mapped out the relationships between the earthquakes and the volcanic features
that were in Bob Christiansen’s work. And then that then turned this into “Let’s
get a permanent network”. Well the USGS installed a permanent network in ’73 they
gave it up in 1980 and said to me “Bob you take over the Yellowstone network, you have
the drive and the Interest”. I said “I’ll take it over if I can grow it to my own dimensions
and reliability. Yellowstone operations are not California operations. It costs a lot
more to have reliable equipment. And they agreed to pay for it. We expanded the Yellowstone
network in the 80’s and then in the late 80’s GPS started to come in and so we started
doing portable GPS studies and integrating the two right here. University of Utah is
the base of operations for all of the Yellowstone earthquake volcano or deformation monitoring.
That’s an important feature that Bob Christiansen’s always said. And it’s true. So, we had all
this data coming in together and then we began to evolve, modernize as more and more digital
equipment came in as bigger and better computers would come in bigger and better data bases
would come in. And so, that came up through the 80’s I had funding from the NSF to start
the GPS, NSF funding start the seismic, got USGS funding. We upgraded the seismic network.
The Park Service has always been very very helpful with us providing us all kinds of
logistical support. Interviewer:
How is new technology helping to conduct earth science? Bob Smith:
Well certainly when I first began studying in Yellowstone the instrumentation, for example
the seismographs were very crude they were recording on paper , smoked paper drums or
on inked drums, we had no GPS, the actual sensors were very low magnification would
only detect relatively moderate to large earthquakes. Well it’s because of computational methodologies
the whole area of seismic monitoring has evolved greatly so that in currently we now have seismographs
that are now capable of magnifying ground motion even from as small as a magnitude zero
earthquake to a magnitude 8 earthquake and remain on scale. Space technology came in
the mid-80’s. We have GPS so we’re using GPS to actually measure a point on the ground
and if we measure with time it represents ground motion and so it’s just like a seismograph.
And so these new technologies primarily GPS and high quality broad band seismology that
we receive funding by the way from the USGS to upgrade to the newest system. We now have
in Yellowstone a network of 39 seismographs putting out a hundred channels of real time
data and about 25 GPS systems putting about 60 or 70 channels of real time data. All of
the data are recorded digitally that means they have high fidelity they’re very reliable
but they’re in real time. That means they get to my laboratory here at the University
of Utah the same time that it gets anywhere on the web. So, anybody can have access to
our data any time they want. Interviewer:
Describe your collaboration with Bob Christiansen Bob Smith:
Bob and I worked together for years, very closely I would spin off geophysical findings,
he would spin off geological findings and how they fit was uncanny amazing. I mean he’d
talk about the volcanic history of a flow and I’d say well here’s the gravity signature
of that flow that tells us how deep it is. Or the seismic data here tells you something
about a fault that’s there that you’ve got on your map. So, I worked really close
with Bob Christiansen and his thoughts pervaded my basic interpretations. So, I think, his
mapping, his ideas of the caldera formation. My ideas of the processes of the magma chamber
how they were formed. How big earthquakes occur and map out the faults that are related
to the magma chamber really fit together. I worked to a certain degree with Bob Fournier
because I was bringing my information to bear on hydrothermal systems, geysers, hot springs
etcetera. So, I got to know Bob very well and so I worked with Bob for several years.
And I still am in touch with he and Bob Christiansen. And it’s always been very rewarding to put
all of our ideas together, you get a better solution, you get a broader solution to a
problem in the case of Yellowstone. When we bring the volcanologists together with the
geophysicists we one can constrain the other data. The earthquake information can constrain
the size of a magma body. The size of the magma body tells the volcanologist how much
magma there is that could be exploded. It tells the geochemist what percent volume of
melt to solid rock in the case of a partial melt. These things are done by people working
together and collaborating and talking to one another routinely and that’s the part
that I would say in the last part of my career that’s been so fun. Because I get, I learn
new things all the time and so productive. Interviewer:
How did road surveys help clarify the story? Bob Smith:
I knew from the earthquake data, Yellowstone was really active. And yet you continue measuring
earthquakes and I said to myself, what we ought to do is measure the ground motion well
back in the 70’s the only way your could do that was with leveling that is engineering
spirit leveling. And so we formed a team that was funded by the USGS and a leveling team
came from the USGS topographic division came out and we began leveling. Now before that
I went to the Washington archives and got the old benchmark descriptions when they built
the roads in 1923 and we were, we were going to the same bench mark the same roads, we
were half way across Hayden Valley and as you go along you calculate you know you’re
walking so you can calculate what the elevation was in 23 and what it is today. And we got
further and further and we kept getting further and further in the numbers. I finally got
half way and I said to M. David Cummings, the surveyor, we’ve got a big problem. We
need to go back and resurvey this whole thing because we’re off two feet. He says ‘I’m
not off two feet”. “I might be off one or two millimeters but not two feet”. We
finished the survey, came back to the university, I spent an entire year and a PhD thesis trying
to take these data and prove they were wrong. They weren’t wrong. We had measured 750
mm of uplift, almost one full meter between 1923 and 1976 in the middle of the caldera.
That’s when we discovered Yellowstone had this very very high uplift rate. And it’s
because we were being very careful we were scrutinizing the data we worked very hard
to prove it was wrong. And we couldn’t. Interviewer:
And now you use GPS? Bob Smith:
Now we use GPS. And we have 25 permanent GPS stations that we run in Yellowstone plus we
go back into areas of Yellowstone another 30 points are measured annually, we call them
annual measurements to fill in, get more detail. But the GPS is now giving us full pictures
of the whole caldera. And we’re supplementing that now with INSAR that is satellite radar
information, actually it takes a picture of the whole caldera and you have a pass every
two weeks. And then the sentinel satellite is just going to come on board next month
for Yellowstone. We’re going to be able to get a picture once every two weeks. The
problem with the INSAR satellite is it measures the top of the ground if there’s snow it
measures the top of the snow so it doesn’t work in winter. And that’s where the GPS
is continuous. And our GPS receivers are now so accurate they measure the height change
within millimeters and the distance change within millimeters per year. That’s the
width of your it’s an amazing technology. But, they all have to be worked together.
But, like I said INSAR, GPS, earthquake data they have to be interpreted together. One
constrains the other. Interviewer:
Describe how you work with the new generation of scientists like Jake Lowenstern. Bob Smith:
He and other people of this next generation are going to be using new techniques I’m
sure built upon what we’ve done. And there will be another generation after that. Because
science develops new things and that’s always guaranteed. Interviewer:
How does plate tectonics relate to Yellowstone? Bob Smith:
One of the basics of Plate Tectonics are plumes, one of the four, you know subduction zones,
extension, strike slip and plumes. Well that’s what’s happened at Yellowstone. So, I made
up some conceptual models for Yellowstone in 1969 on how a plume could come up and well
magma up and give us the heat that we’re seeing at Yellowstone as a hot spot. So, I
published that paper, gave the oral version, ’69. Published it in ’70, first started
to publish in ’71, ’72, ’73, ’74 so we had it all down then. We didn’t have
the new tomography, we didn’t have the new GPS, these were conceptual models, they were
based on earthquake distribution topography and geology. So, plate tectonics had a profound
effect and that’s when I named it the Yellowstone Hot Spot and that it was a mantle plume. I
didn’t say it was a deep mantle plume I said it was a magma plume. Now we know it’s
a relat…it’s an upper mantle plume, goes down to about mid-mantle. Interviewer:
How does Yellowstone volcanism compare to Hawaii? Bob Smith:
The difference between Hawaii and Yellowstone is the following. The crustal structure of
oceanic plates are much thinner and they’re much younger so the magma’s that come up
from the mantle have a much shorter distance to burn through and create the volcanoes.
Moreover the continental crust is much thicker much older and contains much larger components
of silicic rocks. Old old rocks from evidence of billions of year old rocks so when you
heat those up you not only bring up basalts from the mantle the mantle in turn burns the
lower crust, mid crust was a lot of silicic material you get rhyolites. So, in the case
of Yellowstone the rocks that come out are rhyolitic. And they are the first, they are
the flows that we see in the Yellowstone Snake River Plane. They’re followed by the primary
basalts after the plate is moved over the hot spot but the difference being one is a
ocean plate of pure basalt one is a continental plate, big thick and cold that mixes in the
magma adds in the silicic component that creates the rhyolites, the granites we see at the
surface. Interviewer:
How does the University of Utah work with Yellowstone National Park? Bob Smith:
The park interacts with us because all of the data we have here we send back to them
in real time. So, they have access to all of our seismic data, our GPS data just as
fast as we have it. The park doesn’t have professional seismologists or geodesists so
what they rely principally upon us for is a level, is interpretation of the data. So
what they call upon us is what does this mean. What does this swarm of earthquakes mean,
where is it. And so we provide the basic data, the meta data and then, for the park, and
then provide interpretational data and maps and create images for them of our data that
they use for their own teaching and for their emergency management. So, the big, the very
important issue in Yellowstone is public safety and the Yellowstone Volcano Observatory is
set up to provide data for public safety and management of hazard issues. Interviewer:
Talk about the more recent lava flows in Yellowstone National Park. Bob Smith:
There’s been about fifty or sixty post caldera flows dominantly of rhyolite there was some
basalts, these are flows that come out not necessarily explosively or catastrophically
they may cover only two or three or four square miles they are only a few hundred meters thick
at most and they generally don’t leave the park. They don’t leave the actual caldera
or the volcanic plateau. So, these are not deemed to be a national threat but these are
the types of features that have followed the super eruption of 640 thousand years ago.
Well the youngest of these is 70,000 years at the south end of Yellowstone, it’s called
the Pitchstone Plateau flow and it is right at the very south edge and it’s a high piece
of topography around the caldera rim and that’s the youngest and we’ve seen nothing since
then. Interviewer:
Any epiphanies related to Yellowstone National Park? Bob Smith:
The occurrence of the Hebgen Lake Earthquake was an epiphany, the discovery of this gigantic
uplift of the caldera to 1985 followed by an ’86 earthquake swarm. Wow that was something
that really got us tuned in. And then the caldera went down, in 2010 it went back up
again. We had an accelerated uplift from 2004 to 2010 called it accelerated uplift it was
going up at, it went up 25 centimeters, a quarter of a meter. While you don’t see
it in your footsteps you know that those are rates that are higher then geologic rates,
or higher than, faster than San Andreas Fault is loading. Now this last week, we just discovered
now, very carefully, that the caldera is now returning back to uplift and it’s going
up at 40 cm’s a year. So, we view this caldera as this living breathing thing and I argue
that all these little earthquake swarms that we have are really just relief valves so if
we have a lot of swarms that tells us fluids are squirting out of the magma body and if
we keep having swarms and squirting out we’re fine if we stop that process this magma body
is going to inflate and we could have an eruption. So, keeping track closely of the GPS, measure
ground deformation with the seismic activity in the swarms is helping us to understand
the state of the system in terms of its capability and whether it’s an immanent threat or not.
And I’ve had epiphanies my whole damn career up there. Interviewer:
How else is this information shared? Bob Smith:
I had an NSF sponsored workshop on Yellowstone and we had teachers K through 12. These people
saw all the data. They took the data away to use as teaching. So, what I do with my
teaching and all the information I get my books my talks I give all my figures away
to teachers to National Park Service Rangers. We give everything we have to the park service
interpreters who meet millions of people a year so I view it as a multiplying factor.
By doing this and providing it I can multiply my thought, by thousands, by giving this information
out. And I see it come back years later all over the web of the idea and the map that
I made that I gave to somebody and then give it to somebody else so it got passed around
and used. So, to me that’s what distribution of information is about. And that’s what
education bases itself on. Interviewer:
How has public interest in Yellowstone changed? Bob Smith:
It was 2004 when the public became aware of Yellowstone globally that’s when the BBC
produced the super volcano and we were consultants. And that documentary was actually correct.
They just took a very rare feature and made it assume it was immanently going occur. Well
that brought alive the fact that Yellowstone is a geologic park. Before that they didn’t
think of it. They thought it was an elk park and fish park and geyser park. Now people
understand it’s a geologic park and now people are understanding not only that it
has magma chamber it has a plume and it’s a major element of plate tectonics. It’s
truly a living breathing shaking caldera. And this all comes back to the idea what are
the processes. What are the physics of the motions. What are the chemistry of the fluids.
How do they work together? END

Author: Kennedi Daugherty

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