Lost in the fog of a cosmic storm Floating on
whimsical wavelengths is the norm Dancing through
the stars, chasing spectrums of light Mars on
Mars. Say that ten times fast. It's time for
Whimsical Wavelengths. Today is looking at volcanic
eruptions on a neighboring planet. That being
Mars. Looking into the rock record is always
like detective work. Collecting measurements
and clues to slowly piece together the past.
Doing that on another planet is even harder.
No one is there to pick up samples or walk the
outcrops. The first word that started this episode.
Mars. M -A -A -R -S. So no, not the planet. Mars,
we have them here on Earth. They're formed by
violent interactions between rising magma and
subsurface water or ice. Okay, like a lot of
things, the name sort of hides a few terms. If
I would expand it a little bit, the full phrase
for this type of volcanism would be Frito -Magmatic
Mar Diatreme Volcano. Yeah, a mouthful. Let's
break that down a little bit. The first word
is phrytomagmatic. Phryto is a prefix coming
from Greek pertaining to water. Magmatic? Well,
that's magma. Hot, liquid rock under the ground.
So this first word indicates steam explosions,
which include magma. If you're looking into this
on your own, you'll probably see the term phreatic.
This is still a steam explosion where the heat
is still due to magma beneath the ground, but
no magma was included in the eruption. Yellowstone's
geysers and the occasional bigger explosions
from that same system fall into this class. Marr
is a description of the geometry as well, or
the deposits left behind. because they leave
a broad, relatively shallow depression that cuts
into the country rock. So that's just the rock
that was already there. Often below the original,
pre -eruptive surface. So they'll show up as
kind of like holes, or depressions. These features
get shorthanded into Mars, in both the literature
and in common speech among us volcanologists.
Finally, diatremes. They're the broken pipe or
carrot -like shape left behind by the rising
material that erupted. From Kilauea to Messiah
to the Cascades, we've covered plenty of volcanic
styles on this show, but this one is new to Whimsical
Wavelengths. We'll get into so much more in a
moment, when our guest arrives. But I feel it's
important to iterate on one thing. Finding them
doesn't just record an eruption. Remember, you
need groundwater, so they record part of the
environmental conditions at the time they occurred,
if you could find evidence of them on. Mars,
the red planet, you could infer environmental
conditions on a distant planet when that eruption
occurred. Constraining past environmental conditions
on Mars, that would be huge. If Mars, M -A -A
-R -S, really existed on Mars, it means the god
of war might have had to share the stage with
the god of fire. Mythologically... word to discuss
mar volcanoes and the hunt for them on mars and
what we can do with them all right so please
welcome to whimsical wavelengths professor at
the university of missouri kansas city dr allison
grettinger hi there and you know what we we met
way back in 2007 i think it was um i think we
might be getting old at messiah volcano where
both of us were volunteering with dr guillaume
marie You also, like me, volunteered at the Hawaiian
Volcano Observatory as well. How did all those
things come together? Was it like a high school
straight into volcanology or like from a little
tiny kid like wanting to poke lava with a stick?
Or was there like a meandering path? I might
not have been that ambitious when I was little.
I definitely wanted to be covered in mud as often
as possible. But I was lucky enough to meet somebody
that told me geology was a thing. And how do
I get there was chemistry and geology in high
school. Didn't have geology. So when I finally
took my first geology course, it was sort of
a trust this process and dove right in. In college,
it worked out. And my professor eventually told
me that I could study volcanoes like that. I
needed permission, apparently. I thought that
was made up. I wasn't being in movies. And he's
like, no, you don't want to just do petrology.
I don't want to just study crystals and things
that I can't touch directly. He's like, go play
with volcanoes. Wait, he actually said that?
You didn't actually ask? He was just like, clearly
you like volcanoes. Go. go right because i was
asking about grad programs in igneous petrology
which would have been behind the microscope um
you know some field work maybe but he's like
no that's not right for you no so it's somebody
who was you know a faculty member who listened
really well and i will always be grateful for
that because then i was brave enough to run off
to new zealand for a master's which was wild
but that was partially because i had bad test
scores and new zealand didn't care about my test
scores and so when i didn't get some perfect
shiny position in the us i ran off to new zealand
and they happily trained me up from where i was
to the next level and to get to nicaragua i was
just on a mailing list and again it took a bit
of a leap of faith that like come meet us in
nicaragua um and and it worked out and i now
still talk to you and i talked to some of the
other folks who went with us and I just got to
see Guillaume last summer, which was awesome.
Awesome. So humans are such a big part of our
journey. Like it's, you can't have a perfect
path. Life of course intervenes, but it's the
humans who can help you see what you don't see
or to, to trust you and take you to the next
level or say here, go hike through that gas plume
with a battery on your back and dig some holes.
And see if you like it. And to be fair to all
those listening, that is almost exactly what
we did at Messiah Volcano. I don't remember the
battery so much, but I do remember the wire,
the tools, the electrodes, and the gas plume.
We had a magnetometer for a day. That's why we
had a battery. Yeah, there was a magnetometer
for a day. It was a lot of really dusty, sweaty
work because at that time in Nicaragua, it was
the dry season. And every time you dig, there
was like this puff of both soil and ash that
kind of wafted out over you, which stuck to your
sweat. And so you had a number of different colors
by the time you got home due to SPF dirt, as
I like to call it. It was effective against UV.
We're here to talk about Mars. And I'm pronouncing
that right. It's M -A -A -R. But it's still Mars.
You can blame the Germans because the type locality,
or at least the first location, was in Germany.
And so that was the name given and it stuck.
Well, I'm all for whatever name as long as it
stays consistent. Maybe one of these days I'll
get into with diatremes, which we will also be
talking about, but dimeriferous diatremes. They
have all kinds of weird terminology that doesn't
exist anywhere else in volcanology. Which drives
me crazy. But I'm already convinced as to the
reason why we need to study Mars. I'm biased.
All things volcanic or basically all science,
really. But for the listener, what makes sense
that why are these like important to study broadly?
Yeah, so the whole reason I'm interested in Mars
is they look unassuming because we frequently
discover them as these shallow sloped. rises
with a little lake in the middle and they're
frequently completely covered in farmland or
pastoral grasses and it looks non -threatening.
However, the eruptions that formed them that
made that hole in the ground were explosive and
if we are overlooking them we're missing out
on a pretty significant hazard. Now they aren't
the most frequent of volcanic activity, but it's
one of those high risk scenarios that if it does
happen, it's a big enough problem that we do
need to understand where they are, how often
they occur, what else could happen besides the
MAR, what other types of eruptive activity, and
how to better prepare in the future. All of that
comes from just staring at what already happened.
Okay, so how... How big are we really talking
about if they're a hazard? You know, we're not
talking about yellow stones, geysers throwing
some rocks in the air. We're talking about something
much more significant than that, aren't we? Right.
You could potentially have an eruption that's
as small as the geyser scale where rocks are
thrown a few hundred feet or tens of meters.
But more likely, we're going to deal with particles
going. one to two kilometers from vent and if
there are pyroclastic flows they're measured
anywhere between nine and some studies suggest
maybe 15 kilometers from the source now one of
the other problems is that source the point where
you're like okay that's the where the bad stuff
comes from and we're going to measure a buffer
zone around that that moves during the eruptions
and that's something i've spent a lot of time
looking at and they can move several kilometers
within it which means your hazard zone is moving
And there's also the possibility, if it has a
tall plume, some of the few historic eruptions
of these we've seen can have quite tall ash plumes
that would then affect air traffic and then blow
ash and dust downstream. Now, it's not going
to be the biggest, scariest eruption, but they're
frequently in locations where you don't have
the smoking gun, as it were. You can point over
and say, that big cone, that's the problem. They
tend to be in distributed volcanic fields wherein
we have a bunch of little cones and we don't
quite know where the next one will be. And so
preparation is even harder. So your threat zone
might be smaller once you know where it is, but
half of it is not knowing where it is within
a several hundred square kilometer area. Suddenly
it makes the whole problem larger, even if the
individual eruption if conveniently located,
might only affect a few people, but if inconveniently
located, is really bad. Okay, we're going to
get off topic already, and I love it. So that's
not exactly where I thought this was going to
go. I got two questions. First one's probably
quick and easy. Like, how big of an eruption
could we be talking about here? Like, are we
talking Mount St. Helens size? Like, that's what,
one cubic kilometer in 1980? Are we talking something
half that size? Base it off of Mount St. Helens
scale instead of the metric. So one cubic kilometer
worth of melt is probably the biggest that we
would expect for these types of eruptions. And
most of them are smaller. So we're probably talking
one step down on that volcanic explosivity index
to, you know, I guess it would be a four on the
VEI scale. So volume wise, individual eruptions.
not that intimidating. We call them small volume
volcanoes as one of the many designators when
we're sort of lumping in, say, a scoriac cone
or a mar, or we also have a handful of sort of
in -between features where if the mar is this
excavating volcano and a scoriac cone is a small
volume constructive eruption, there's some in
-betweens that we can get into if you want, but
we can also just leave on the side for now. Think
of it as a continuum. Yeah. It's like this in
every science. The deeper you get, the more messy
it gets, I think. But I wanted to get into something
messy as an aside because you mentioned distributed
volcanic fields. Now, the vast majority of listeners
are going to be familiar with the Cascades. They
have these locuses or concentrated points of...
stratovolcanoes they're all concentrated there
is a section in the cascades which is not so
concentrated and that's around south sister in
the bend area i can't remember off the top of
my head what that field is called and around
newberry there uh well there's the boring volcanic
field which is bend and then there's the cluster
south of newberry there's also some to the north
they're kind of scattered behind the arc if you
think of the main chain of volcanoes as the arc
then behind that you tend to get little clusters
and there's hundreds of them and sometimes they're
in well -known groups like near newberry and
sometimes it's one or two little little dudes
hanging out by themselves and so when they're
next to the cascades like that um they kind of
get lumped in in some of the maps we make or
when we're doing hazards But there are also distributed
volcanic fields that are further from an obvious
tectonic boundary. So in Utah, in Nevada, in
Arizona, California, we've got some of these
distributed fields is kind of the term we're
leaning towards right now, where the majority
of activity is one of these small volume vents
of a range of different eruptive styles. And
they're scattered around and there can be several
hundred. over a broad region or you can get into
colorado where there's like three and they still
need to somehow be compared to something so that's
why we use this term right but the more long
-lived ones not necessarily the cascades i think
there's lots in mexico and new mexico as well
like what creates like these long lived with
process wise like creating these distributed
volcanic fields Yeah, so we need two things.
We need a system for generating magma, and then
we need pathways to the surface. So frequently,
these are occurring in areas of extension where
the crust is being pulled apart, and we have
slight depressurization of the mantle beneath
it, which then there's faults and fractures created
by that extension, which tend to dictate the
position of where these volcanoes might be above
them. and so behind some volcanic arcs we get
that extension sometimes there's larger tectonic
processes like the basin and range in new mexico
a lot of the distributed volcanic features are
associated with the rio grande rift which is
a slightly more concentrated zone of extension
we could leave north america and there's examples
in south america there's in the philippines You
can basically find them on most continents. France
has some older ones. There's examples in Spain
that are also older, but related mostly to extension,
though that extension could be connected to subduction
or it could be other tectonic processes. The
challenge to remember with earth and plate tectonics
is that they're all happening at the same time.
bit of earth has had a long volcanic history
so they could be really old fractures that are
being leveraged they could be reactivated due
to some new tension related to a different tectonic
process and that's where we find these is sort
of complicated adjacent tectonic provinces that
usually are more extensional than not okay so
for those who need a refresher course you can
go back into the whimsical wavelengths Episode
library and there we've talked about how we generate
magma lots of times So let me just rephrase this
and hopefully I've got everything we can summarize
and then move towards the paper, which is on
Mars And I meant the planet not the volcano.
So I guess first thing we need is some kind of
Feature that allows more magma to come towards
the surface usually extensional usually as part
of some other system often to do with back arc
basins so you could be getting a number of different
sources as to why you have an increase in magma
there. It's distributed so it's not coming out
as a locus and I think there's one part we missed
is that you need to have some kind of shallow
groundwater to have the interaction. Yeah we
hadn't actually hit the part about why we have
excavation with these is that it does need to
interact with groundwater or ground ice and that
water can be in your traditional aquifer. in
some nice stratigraphic unit water hanging out
between sand grains or in faults can be also
associated with things like permafrost or if
you have a swampy environment you can also create
this kind of feature so the idea here is that
you interact with enough water that it all flashes
to steam and that steam needs to expand and then
it expands so fast that it causes failure of
the rock This is the fun part where I can say
yes and. So steam we know is powerful. We've
made engines based on this steam expansion, right?
It does a lot of work. But one of the fun things
we've gotten to learn by taking molten magma
and trying to blow it up is magma plus water
does not automatically make explosion. If you've
ever watched some of those fun videos from Hawaii
where lava is going directly into the ocean.
We also had videos of this from La Palma in Tenerife,
the Canary Islands in 2021. It doesn't blow up
all the time. It kind of waits. It's intermittent.
So what's different? So it's not strictly...
only steam expansion. The steam's definitely
contributing, but there is a heat transfer process
that is faster than even steam expansion, which
is kind of mind -boggling when you first encounter
it. But this transfer of heat away from the lava
into water. Water is the most efficient coolant
we are aware of on this planet. It's one of those
reminders that like Earth is wild because we
have all this liquid water, which doesn't behave
like all other materials, right? Like when you
freeze it, it becomes uh less dense which is
unlike most other materials and when in its liquid
form it is it's this really effective coolant
so it sucks the heat out of the lava fast enough
to shock it and that shock then releases mechanical
energy so it's a thermal mechanical shock that
results in the production of shock waves which
breaks more things which lets more water in which
leads to more shocks which also produces the
steam so this combined leads to a faster explosion
than you can produce in other magmatic systems.
And there's like a sweet spot with water pressure,
I gather, like depth inside the earth or depth
underneath the ocean. Yeah, so the heat transfer
happens when you have liquid water in touch with
the magma directly. But as anybody who's ever
thrown a little bit of water onto a frying pan
has seen that that formation of vapor or steam
occurs rapidly and then actually insulates the
water from the pants. So then you have this little
dancing water droplet or the Leidenfrost effect.
That water vapor actually is why most magma water
contact is kind of meh. And maybe some steam
is produced, but if it's not trapped or anything
else, it's not necessarily dangerous. And this
is one of the reasons that these eruptions are
so interesting to me is understanding both the
physics of it and the consequences. And so when
the vapor film's not there, it should be more
explosive. So you could think at those great
pressures, shouldn't it be, if there's no vapor
forming, shouldn't it be explosive all the time?
Also not necessarily. So there's still something
we're working on, the conditions that are ideal
for this rapid heat transfer and the balance
of energy release from the different aspects
of it. But experimentally, we sort of played
around with water temperature, salinity. all
of that does act as a knob on how explosive this
is and how much of that magma temperature that
heat available in the budget gets turned into
explosive energy and the answer is it's not very
efficient it's just really dramatic for the amount
and the speed at which it happens so the depth
beneath the ocean is going to affect that the
availability of water in the system but it's
not some perfect ratio so we had some sort of
starting models and we're like this sounds reasonable
but of course as you said earlier as we dig into
it it gets messier and messier and how do we
turn this into usable science right that can
that can help us be safer that can help us to
plan for it or you know inspire some weird new
steam engine of the future Speaking of steam
engines on Mars, I guess these sorts of things
are really important to recognize in the rock
record because it tells you something about the
environment, right? Absolutely. It's a great
way to reconstruct other aspects of it besides
just the magma. Okay, so one last stop before
we get to the paper. Mar locations, volcanic
locations all around the Earth, there's a database,
a shape database to help you kind of like find
them. do you also train this on AI as well to
be able to search the earth for these types of
shapes? That's a great next step. So I call it
the marvelous database because it's Mar volcano
location and shape. And one of the things we
had to figure out is like, are all Mars similar?
And so we just started looking for the prettiest
ones around the planet. And I think we have a
pretty decent catalog at this point. There's
about 435 and all continents are included. We,
No, there's more, but geology loves to rewrite
the history that it's leaving behind, so some
are missing. And I continue to have students
helping me with this. We're still doing it manually
because while circle recognition, pattern recognition
is actually a great application of machine learning,
we need a proper training data set. And 430 is
a little on the low side for a solid model. So
I need to also have good databases of what I
don't want. as a way to rectify the the absence
of sufficient quantity of the variability we
could find in the original data set at least
this is what i've been told by my colleagues
when they're like you should do machine learning
and i said here's my data set and they go we
need more so we're doing it the old way or the
old -fashioned way which is hunting for them
using people's papers that have said you know
we know this is mars somebody's been there and
checked it hunting through google earth and then
trying to back that up so that we know that features
what we think it is because fascinatingly earth's
really good at making circular lakes there's
other ways to do it glaciers melting permafrost
meteorite impacts um anthropogenic things we
we like circles it's human so they're out there
too And so this is the challenge also once we
leave Earth is there's other circles out there.
And how do we tell them apart? So we need these
sort of anchor points of confidence. And that's
what Marvelous was hoping to be. And in future
versions, I'm trying to add in some of that continua
I told you about where like, they're not all
exactly the same. And the fun thing is, while
they're circles, they're not just simple circles.
Sometimes they look like Mickey Mouse or a peanut.
It's compound structures. And that's when I got
really excited about looking for it elsewhere.
Are we ready to go to Mars? Have you thought
of trying to do machine learning in a slightly
different way? Instead of only building a giant
database, using that database of what you have
and overlying it with other layers like heat
flow? So the machine learning can make the...
inference or tying things like heat flow or structure
to the circles themselves and only where it finds
the same pattern that it can pull it up. Right.
Having multiple tie points. We haven't found
the right companion data set. It could be multiple.
I mean, we use lots in mineral prospectivity.
Yeah. So I think, I think that is a next step
and it's a combination of finding the right data
sets, finding the right partner and getting them
to trial it. And it's been the folks who were
keen had an existing workflow. They wanted to
throw me in and that's where it's not going to
work yet. so what i keep doing is trying to look
for other patterns in it so that's that's the
other benefit of marvelous is in addition to
its location and its shape we're keeping track
of age we're keeping track of composition we're
keeping back of um regional context you know
are we and i tried things like latitude longitude
elevation and we're sort of iterating and We
keep going back to fill in more of these data
sets as things get published or people send them
to me. And that way we can look for additional
patterns besides just where they are to evaluate
if there's something else useful hidden in it.
So I tried tectonic setting. I tried what we
really need is more age and more compositions.
And I think that might be where we find this
companion data set that you were talking about
that we could use as a separate check. Heat flows
hard on these because there's no magma source
anymore. They're done. Right, if it's old. And
they're all such small volume that their thermal
signature would be quite little. I was more thinking
heat flow is like a regional scale. So if you're
looking for something that is potentially active
in the Holocene, then you're going to have an
increased heat flow of the whole area. For instance,
the Cascade Arc has a high heat flow, right?
So that way when you're telling to search the
whole world, it's not like going to Kansas and
going, well, there's a circle there. You're like,
well. It has no heat flow, so it won't exist
type thing. But we do have some fun diatremes
there that are not Mars. They're... Kimberlites?
Yeah, but non -diamondiferous. Yeah. Yeah. Anyway,
we're off topic. It's okay. That's the whole
point. That's why I have a skeleton of a blueprint.
And I'm moving... Thermal inertia. Thermal inertia
is the fun one. And planetary scale, it's actually
easier to do thermal inertia on Mars than it
is on Earth. Huh. There's just a lot of... What?
Okay, well, we're switching to Mars, and I'll
come back to that in just a second, because the
paper at the heart of this episode is identification
of candidate Martian Mars in the area of Coles
and Nephentis Amethys. I pronounced it wrong.
That's okay. With the extension to Mars as a
proxy for groundwater and ice depths. So Mars,
the red planet. And I think we've already stated
why we want to look on Mars. I mean, we want
to find water. We want to find what happened
to Mars over time. But thermal inertia, what
is that in context of a planetary scale? Yeah,
so we can look at the daytime thermal emissivity
of a planet. That is the long wave infrared wavelengths.
So imagine like those old coil stoves. I know
some folks still have them, right? That heat
energy come off it. You're actually seeing it
glow red. That's the emissivity. And so we can
measure that in the day and we can measure that
at night. And so as the sun's hitting a planetary
surface, rocks warm up, soil warms up, the whole
surface will. And depending on the material properties
is how long it's going to keep that heat or how
rapidly it's going to change. And so dense materials
take longer to heat and loose materials, soils,
dust, et cetera, are going to change temperature
more rapidly. So if we're looking for volcanic
deposits, we would expect them to be loose materials.
If we're looking for lava flows, we're expecting
them to be dense. So they should have different
thermal inertia, which is basically comparing
that day -night pair. So what's fun now with
all the satellites we have living at Mars collecting
data, we have a pretty decent... planetary scale
thermal inertia data set. And so that can be
useful for looking at changes in basically material
properties across the planet. On Earth, we have
lots of moisture in the soil and plants and things
like that that make thermal inertia a little
messier. Still can be used, but it's not as easy
for a whole planet wide comparison. But there
is some problems on Mars because there's lots
of dust moving around on the surface. So it's
you know, still a geologic environment and still
messy in all the ways to make our brains work
harder. That's awesome. Okay, so back to Mars.
We have volcanoes and we've had water on Mars.
This is what we infer from the data that we have.
So those two things are similar to Earth. But
what about that volcanic activity in and of itself?
Is that volcanic activity similar to Earth? And
what does gravity have? to do with it all i mean
are there any other things that are different
with respect to martian volcanoes and the processes
that will affect a mar type eruption um such
as gravity like would it change its shape because
if shape is how you're identifying them what's
out there that's going to change how you look
at them okay so i won't answer all the questions
you just opened because some are rabbit holes
let's stay focused i'm going to try yeah sorry
sometimes i'm my own worst enemy um Well, and
also as I can't turn professor off, I always
have a need to make sure there's a root understanding.
But let's let's stick with Mars on Mars. And
can I really play this game of I know what they
look like on Earth. So this is what they should
look like on Mars, right? That's the that's a
great question. When we're thinking about it.
Our ideas of magmatic compositions for Mars,
we're expecting them to be still similar. Silicate
melts probably pretty mafic based on some control
data we have from meteorites, from satellite
remote sensing that indicates we should expect
some nice runny silicate melts like on Earth.
So for the majority of Mars, which have that
composition, that's not a problem. As the magma
rises and encounters groundwater or Ground ice
might be the case on Mars, and it explodes. It's
then going to be lifting rock above it. And so
your question was, does gravity matter? Yes,
but what's it going to do? So we have a good
idea of ballistic particle, like take yourself
back to physics, right? When you're just like,
if I throw a rock from here, it's going to fly
in a parabolic arc, and gravity is one of those
major controls for how far away it can go. So
that should influence it somewhat. But the challenge
I was trying to point out earlier from a hazard
perspective is that it also moves. So if you
have a point source and you see how far away
things go, you can back calculate that source
location. But if that source location likes to
move around, you know, sideways, vertically,
you know, left, right, east, west, north, south,
all the options are possible. When you look at
that deposit, you start going, well, is it actually
bigger or smaller than on Earth? Generally, most
things Martian are bigger. So that's a good go
to. So my search parameters, I was like, I'm
just going to look bigger than I expect on Earth.
And also atmospheric pressure is different. So
that's going to affect things like drag, which
is again going to influence whether you're going
to produce big poofy columns of ash rising that
could collapse. Are we going to have more things
just going up and right back down? It's going
to affect some of those physics that would affect
the distribution of material around it and how
steep a wall you can keep in your hole in the
ground. So the answer is yes. But unlike with
scoriacones, where we're mainly just piling up
debris around a point source, it's harder to
just adjust the model. So it comes back to let's
look for them and see what we find, knowing that
we're going to have to look a little bit broader
than what we see on Earth. And the main tie point,
why I felt confident that I could do this, goes
back to that Mars aren't just circles. We have
circles, but it's something like 13 % or less.
of the database were simple circles. And so that
leaves us the majority, which are compound structures.
And of those structures, when you can see that
it's intersecting circles, like a little mouse
character with a copyright on it that I don't
know if we can name. Yeah, we can. The original
has entered the common license. Public domain.
Okay. So if you have a Mickey Mouse shape, or
if you have a snowman, where you have these overlapping
circles and you can recognize those discrete
circles, that is a unique shape. Other holes
in the ground on Mars, especially impact craters,
which are all over the place, they tend to be
more elliptical to circular. The vast majority
are circular. Funky shapes do exist, and a lot
of the funky shapes we find tend to be volcanic.
We're going to look in a specific size range,
slightly augmented for Mars. We're going to look
for them being distributed. So not all on some
larger edifice, but sort of spread around and
ideally with other volcanic things with them.
So I found we started in Arenicolis because somebody
else said, I see these cute little cones that
could be scoriac cones. Maybe they have a little
bit of magma water interaction to make them have
bigger summit craters. And nearby, I saw these
really big, holes, some of which looked like
compound circular structures. And I said, OK,
how many can we find? And we were inclusive at
the beginning. And then we made this checklist
of what is an inclusive criteria versus something
that's going to exclude it. And so I had to get
to know impact craters better, especially when
you have an impact. The debris that flies from
that can also make impacts. And those are messier
than the first one that's flying at the really
high velocities. The secondary craters, what
they're called, are a little bit more irregular,
but they tend to all radiate away from some point
source. They tend to be really asymmetrical where
a lot of the debris is on one side and not the
other. And so we could use that sort of contextual
information to check off what was a good candidate
from something that was probably something else.
Did I actually answer the question? I don't know.
Yeah. almost answered the next question too okay
first off how many did you find so we started
in the order of like 70 holes in the ground we're
like we have holes and then we we narrowed it
down and so there's 12 that i think are meeting
the criteria and what's exciting about that is
So far, there isn't a better explanation for
them. Now, I'm one of the few people who've stared
at them closely and somebody else could very
easily come in and look at them and spot something
I missed. But that's the fun of science, right?
It's like I get to make this list and say, all
right, here you go, guys. Go check them harder.
Let's see what else it could be. And I also have
people who are like, okay, based on your rules,
I'm going to go check my holes in the ground
in a different part of the planet. And we'll
see if this system works elsewhere. And it's
kind of fun. To wait and see, oh, I wonder what's
going to happen. And the longer people go, well,
seems reasonable. You kind of go, really? I thought
I was on a planet. I'm nowhere near that. But
we can try that. And it's a great opportunity
for testing my models about Earth. It's a great
opportunity for us to think about how well we
understand those other processes that I was excluding.
And even that little bit of going outside of
what we know to like maybe. still helps us learn
and is part of this whole scientific endeavor.
Okay, well, taking this full circle, how does
this now change your thoughts when applying,
looking for this stuff on Earth? So we've had
some questions about the role of ice versus water.
And I wanted to do some experiments, and we've
sort of goofed around with lava and ice. I'm
saying... Wait, wait, wait. You goofed around
with lava and ice. I never thought I'd hear that
as a phrase. The reason I'm using such a flippant
term is it's sort of the preliminary tests to
see what's feasible before I get into some really
rigorous. We're going to test all these variables
because I've worked with molten lava between
60 milliliters and 60 liters in. dry and wet
conditions and we had some pretty good constraints
on how it's going to handle so that we could
design the experiments and then iterate through
it. So we were looking at the roles of like porosity
and permeability. So how the water's in the material
that's hosting it and whether it can move through
it so that we could understand steam formation
and how this moves around. And we're like, all
right, so when we do ice, how should we do this?
And I made what I call sediment popsicles. and
just froze sediment and water together and to
control how much we had i said let's go ahead
and just saturate the sediment right so there's
just as much water as can fit between those particles
and then we freeze it and i was thinking oh when
we did plain ice experiments where it was lava
plus water the what the ice melts we have to
capture the water so we could calculate the thermal
budget how much energy was put into melting the
ice and so we spent an hour or two to try and
slope the whole surface to catch the water in
a bucket and then there was no melt water because
with the particular sand we were using the permeability
is really low so the steam sort of forms and
stays in the sand and then eventually leaks out
so we're not there's no water pouring out of
this system oh okay so that's what I mean by
goofing because we have to do some of this initial
testing to be like well what are we gonna measure
when we want to be able to say something systematic
about this. So we haven't done nearly as many
as I'd like to start calling it a true experiment
yet. But in that process and in the process of
looking at Mars, thinking about, well, what's
the difference when it's solid and needs to be
melted? Because ice is not as good a coolant
due to it being solid and water having the right
heat capacity. to be able to transfer energy
so effectively. So we still have to melt it to
get the fun interactions or the dynamic interactions
that produce these explosions and could excavate
the ground. So that step matters. It's forcing
us to then go look at Earth and we're like, well,
where did we have ground ice? We know it's happened
on Earth. There's the biggest in the world actually
are six kilometers across in the Seward Peninsula
of Alaska. And are they big because they're permafrost
or are they big because of other things? And
is it permafrost during the eruption or is it
permafrost melting afterwards? And of course,
this being out in the rural Seward Peninsula,
this is like helicopter work and bears and there's
all these massive lakes and it's boggy and it's...
You're not getting there quickly. So there hasn't
been as much work on them. So then I started
going, well, are they in the rock record? So
now I'm going back to Marvelous and I'm looking
for how many occurred in older permafrost that
maybe isn't permafrost right now and we can go
work on it without damaging it or being at risk
of bears. Is there enough methane in the permafrost
there? Just randomly came to my mind. Right.
What does methane have to do with the story?
I don't know. For listeners, there is the ability
to store a lot of methane in permafrost. In fact,
they have methane explosions in some areas of
Russia that they have craters for that are not
volcanic. Which make fun holes in the ground.
They do. What makes them different? They tend
to not throw out as much stuff so they don't
have as big a crater rims. But I had to go through
that exercise. So like I want to be a volcanologist,
right? I care about. But think of all the things
in just this conversation we've had to get to
to solve this problem, which is why I love it,
because I'm forced to learn about periglacial
environments, which is, you know, near glacial
environments, permafrost, methane explosion holes.
And and then thinking about. What would these
other compounds do? And if we want to go even
more complicated, on Mars, they have CO2 ice.
So if we're dealing with CO2, how well does that
work? I haven't goofed with CO2 ice and lava
yet, but I will someday in my career. Or somebody
else will, and they'll show it to me, right?
So I could wait for somebody else to do this.
There's only so much time one human can do, and
so it has to be this collaborative... Collaborative...
effort to get all of the fields we need the physics
the geology the atmospheric science the planetary
science the organic chemists the you know right
like we have to have friends and we also have
to chip away at this big problem so that's why
i like experiments that's why i like planetary
because it feels very tangible about how you're
pushing knowledge or testing something. And sometimes
that can be harder to imagine for folks who only
took chemistry and like experiments are these
really set things with like an answer at the
end. The experiments in geology can be me pouring
lava on things, see what happens, poke it with
stick, go yay. But can also be just, I have a
model. does it make sense with the rocks? And
we need all of those approaches. And so sometimes
with planetary, you get to throw a wild idea
out there and like, but what if guys, and, and
there's sort of more freedom for that there than
on earth where it's like, you really need to
get into it, but it makes you ask bigger picture
questions. And sometimes we have time to, and
we're so down the rabbit hole of what we do know
or what we've been working on for our whole career.
So I encourage anybody who wants to do planetary
to. to see how your world might fit into it because
it will make you really question your fundamentals
and sometimes just realize oh man we know less
than we think we do i have work to do here which
is perfectly fine as a result right it's either
way you're gonna you're gonna move on yeah i
feel like getting a phd was more about figuring
out what we don't know than really learning anything
at all okay so let's just try to i've already
had you here for a while now getting closer to
the end i feel like we need to ask some questions
we actually answered some questions hey i've
got no complaints i also learned a lot about
mars on mars i just i can't get over how that
sounds it's my new favorite tongue twister of
all time um but one question that i think we
need to summarize is let's assume that these
are mars on mars besides sounding cool what does
it actually tell us about mars the planet So
the fun thing about volcanoes for solving other
research problems is they represent this sort
of specific moment in time where something happened.
And at that time, it's telling you about the
conditions needed to make it happen. There's
magma and there is this water in whatever form
it's in and it's underground. So the next step
I did in the research was like, well, so if these
two things are true, constrained by my candidate
Mars on Mars, Can I say something about where
that water is other than just down there somewhere?
And this is where I had to look at the old eroded
volcanoes on Earth rather than just the fresh,
well -preserved ones, because we needed to look
at the volcano guts. And this comes to the diatremes.
So that's that subsurface structure where all
of the... damage from the explosion is located.
And they tend to be these sort of conical, you
know, carrot shaped structures. But the fun thing
is sometimes it's like those weird carrots you
get at the farmer's market, not the grocery store
one where it's got several shoots in different
directions. And I needed to know. well, what
are common shapes and common depths and the angles
of those? And so I got to look not only at my
Mar volcanoes, but I borrowed Kimberlite literature
because in order to get those diamonds and the
other cool minerals that are with them, we've
just been excavating down and going, oh, is it
straight down? Nope, it's slightly off to the
side. And maybe it's three, again, overlapping
circular structures. When you cut these across,
you get... The cross section is circular or a
series of compounding circles. And of that data
that's publicly available, there's more that
isn't that I would love to get my gritty little
fingers on. Yeah, industry doesn't like to share
data. Diamonds, we're a big thing. Yeah, I don't
want to make money off of it, but I want more
data so that I can say what's reasonable. And
then I said, fine, let's make a window of reasonable
angles. And if you project those angles downward.
How far do you have to go? And I also got to
use my experimental data that involved burying
explosives and saying, what shape can I make
in the ground by burying chemical explosives
and then digging them back up? And so combining
all of these sort of disparate data sets, a little
bit of geophysics, a little bit of excavation,
a little bit of experimental, and came up with
this window. And again, threw it out there for
the... the other scientists to say does this
corroborate with what we're seeing from satellite
imagery that's trying to use uh radar to to determine
the depth of it now and so my cute little 12
are this little point pinning possible depths
on mars in one place so if we keep looking and
we get a bunch of pins then we match it with
these other techniques we can start to reconstruct
well just how much water is still there or was
there in the recent geologic past which on mars
recent is a little bit further back than on earth
especially volcanically there's not been a lot
in the last hundred million years but we can
still say from the more recent geologic time
period that there was ice at these depths, probably.
So what else can we check it with? So that was
kind of the fun thing I threw out. And what's
exciting is I already know folks who are curious
about testing my hypothesis. And so they're sort
of keeping me up to date as they figure out how
they're going to do it. And it might take a while
because it's another planet. And then maybe someday
a rover will drive up to one of these. And poke
around and help us to understand it from on the
ground. Or maybe a geologist. I don't know if
I'll be around for that time period. But it's
kind of cool to think about, like, someday somebody
says, hey, yeah, she was full of it. Or they'll
be, like, kind of useful. Yeah, and you never
know. Right. You're always just like, oh, it's
in the right direction. Yeah. Yeah, that's science.
That's science. That's how we do it. Wow. I think
it's time for call -outs because I don't even
know how to follow that up with another question
that isn't going to get us way off track and
down another hour of conversation. So do you
have anything to call out? Future work? Current
work? Favorite movie or documentary that just
came out? Maybe a yellow ducky? Oh, I still have
my duck. But I will admit that it's the fourth
generation duck. For those who do not know Allison,
Professor Allison here, as soon as I met her,
there was always a companion that always came
with her in the field everywhere. And it didn't
matter how terrible the environment was, whether
it was sulfur directly into a volcanic plume
or dragged across any number of different things.
And it was always just as dirty as us at the
end of the day. And so. Yeah, the duck actually,
it's more popular than me at scientific conferences.
And so had I tried to stop bringing the duck,
I probably would not be invited back. So I keep
the duck. So you get keynote speakers because
of the duck. The duck can't speak, so I have
to do it for us. Right. Right. Wow. Any other
call outs now that I've kind of put words in
your mouth? Yeah, I mean, there's more ongoing
projects. I just always like to say at the end
of these conversations where I'm throwing at
random things, like I play with dynamite, I play
with lava. If you're thinking of solving a problem,
be more creative. There's probably, it might
involve duct tape and buckets, but it might involve
some expensive instrument. It might just involve
finding some friends who can enable you. Try
it, because somebody trusted me. to blow holes
in the ground. And we learned a lot from it.
And so you never know what tool is going to actually
blow the whole case wide open. Yeah, I think
a lot of people, the non -scientists really don't
recognize the fact that science is a lot of creativity.
When you're presented with a problem, you have
no idea how to solve it. And sometimes you throw
everything in the kitchen sink just to see what
would happen. That's a pretty good lesson for
all of us to learn. In fact, I do that in my
day -to -day life, and it drives some people
nuts. And I'm like, I'm just brainstorming. I
didn't say it was a good idea. I'm not saying
do that. I'm just saying, like, we have a problem.
Let's try to figure this out. Let me just throw
things at the wall. That's where the sci -fi
bad guy character ideas come from, is just talking
to scientists who didn't really plan on trying
some of those. Okay, so we've come to the infamous.
Last question that I ask every single guest.
And if for whatever reason, which I hope you
do, you come back on in the future to Whimsical
Wavelengths, you'll need another joke. So what
is your favorite science joke? So when you're
trying to discuss whether or not the Earth is
round, I have one argument that is a great way
to end those conversations. And it's if the Earth
was flat, cats would have knocked everything
off the edge already. True story. It just makes
me happy. I take it you have cats then. Surprisingly,
I don't. Okay, well, thank you so much for coming
on. And hopefully that means that you will get
a cat in the near future to make you happy. Well,
I appreciate your time and your patience with
my inability to follow a straight line conversation.
It was fantastic. And I keep telling everyone
who comes on Whimsical Wavelengths, that's my
job. My job is to try to keep it in a straight
line. Sometimes I don't do a very good job. But
this was great, and I learned a lot. Thanks.
Okay, that's another Whimsical Wavelengths that
has been brought to an end. And thanks so much
for listening. This one was great fun to reconnect
with an old colleague and chat about Mars on
Mars. Mars on Mars. Mars on Mars? Mars on Mars.
Mars on Mars on Mars on Mars. I love that phrase.
At any rate, you can catch Whimsical Wavelengths
again in two weeks, and we'll see where the Whimsical
Wavelengths take us. Adios. Swaying to rhythms
as the galaxies fly by