Ep. 607: InSight and Marsquakes

Mars is cold and dead today, but the massive volcanoes tell us what the planet used to be like, millions and even billions of years ago. But how volcanically active is the planet today? That’s what NASA’s Mars InSight lander is there to figure out.

Show Notes | Transcript

Show Notes

May 26, 2021 Total Lunar Eclipse (Blood Moon) (timeanddate.com)

Mars InSight Mission (NASA)

Volcanoes on Mars Could Be Active, Raise Possibility of Recent Habitable Conditions (Planetary Science Institute)

NASA’s InSight Detects Two Sizable Quakes on Mars (NASA)

NASA InSight’s ‘Mole’ Ends Its Journey on Mars (NASA)

Seismicity on Mars Full of Surprises, in First Continuous Year of Data Collection (Seismological Society of America)

Moonquakes (NASA)

Shallow moonquakes – How they compare with earthquakes (adsabs)

InSight tracks down the origin of two big marsquakes (Astronomy)

Tiny Volcanoes Are a Big Deal on Mars (Eos)

Volcanism on Mars (SDSU)

Shield Volcanoes (SDSU)

Stratovolcanoes (SDSU)

Cinder cone (USGS)

Intraplate Volcanism (SDSU)

Eruption Mar 2021 on the Reykjanes Peninsula: activity updates (Volcano Discovery)

Kīlauea (USGS)

Fissure-fed Flood Basalt Provinces (SDSU)

Krakatau volcano (Volcano Discovery)

Volcanic gases can be harmful to health, vegetation and infrastructure (USGS)

Curiosity’s Mars Methane Mystery Continues (NASA)


Mars MAVEN Mission (NASA)

ExoMars Trace Gas Orbiter (ESA)

A Biological Solution to the Mystery of Methane on Mars (Air & Space)


Transcriptions provided by GMR Transcription Services

Fraser:                         Astronomy Cast episode 607 InSight and Marsquakes. Welcome to Astronomy Cast a weekly facts based journey through the cosmos, we help you understand not only what we know, but how we know what we know. I’m Fraser Cain, publisher of Universe Today with me as always is Dr. Pamela Gay, a senior scientist for the Planetary Science Institute and the director of CosmoQuest. Hey, Pamela, how you doing?

Dr. Gay:                      I am doing well. I am sad though, there’s a lunar eclipse, there’s a missing moon in the sky that should be full that occurs next Wednesday and we don’t get to see it. But everyone –

Fraser:                         What do you mean we don’t get to see it?

Dr. Gay:                      Okay. Fine. Fine.

Fraser:                         I get to see it. Yeah.

Dr. Gay:                      I has a sad.

Fraser:                         I’ll report on whether or not the moon disappeared and whether it came back.

Dr. Gay:                      Excellent. Excellent. Remember to slam those pots or whatever you do in Canada to get the eclipse to end.

Fraser:                         Is that how that works?

Dr. Gay:                      I think so. That’s what I’ve been told.

Fraser:                         I’ve never done that. And I’m amazed that the moon is returned every time then. I didn’t know that it was on me. So, it’s gonna be an early morning one and the way things work, I can watch this from my bed.

Dr. Gay:                      That’s amazing.

Fraser:                         Yeah, yeah. So, I can just lay in bed and watch the moon go through the entire thing until morning and they get up for breakfast. Yeah, it’s perfect.

Dr. Gay:                      And those of you in Australia and New Zealand, you are smack in the middle of it and get the best view of all.  So, all of you wonderful humans down under go look at this for me, go look at this for me.

Fraser:                         Mars is cold and dead today. But the massive volcanoes tell us what the planet used to be like millions and even billions of years ago. But how volcanically active is the planet today? That’s what NASA’s Mars InSight Lander is there to figure out. All right, Mars InSight, volcanoes. Is there active volcanism on Mars today?

Dr. Gay:                      Maybe. And this is such a new result. We picked this topic before this science result was published through peer review. And it’s awesome when randomness like that occurs. There is a new paper out with lead author David Horvath. And it discusses how in Cerberus Fossae there appears to have been explosive volcanism as recently as within the last 50,000 years, 50,000.

Fraser:                         Wow. That’s soon. That’s recent.

Dr. Gay:                      That counts as active volcanism today. And what’s awesome is that location matches up loosely with where InSight has seen some well, seismic activity.

Fraser:                         Okay. So, I guess the answer then is maybe. All right. So, let’s go back to the beginning here. Now, I don’t know if we’ve actually done with − I haven’t done an episode on InSight in detail yet, I don’t think. So, can you just give a brief overview of what Mars InSight is there to do?

Dr. Gay:                      So, this is a fabulous little spacecraft that has proven that sometimes a world can defeat the most well-intentioned of spacecraft. InSight landed on Mars with two major missions. The first one was to put down a seismograph that would be able to detect faint earthquakes. And it’s such a sensitive seismograph that it can see the waves of an earthquake if everything is perfect, not just propagate through the world once but, actually bounce through multiple times.

And because of this, they can use a single seismograph to do the science that will require multiple seismographs to do here on Earth, where things are a little bit more noisy, because we have trucks and mining and things like that.

Fraser:                         I’m just kind of imagining this, that you’re getting some earthquake happening somewhere on Mars, InSight detects it and then also detects the reverberations of that earthquake – mars quake as it bounces around the interior of Mars.

Dr. Gay:                      Yes. And this is only possible because Mars doesn’t have oceans creating background noise, weather creating background noise, and all the activities of everything that is alive that create background noise. Now, it turns out that this has been harder than they thought. Because there’s still wind on Mars. So, one of my most amusing things to talk about when people are like, “We need to send humans to Mars because sometimes we have to be able to fix things.”

Well, they realize the wind was creating problems for the seismograph because the wind was picking the cable and just creating slight vibrations in the cable between the seismograph and the spacecraft. So, they’re now using the shovel that’s on an arm on the InSight to systematically bury the cable, as though they were playing in a sandbox. And it’s really delightful.

Fraser:                         Oh, I had no idea. Okay. And so, with InSight on the surface of Mars with its really precise seismograph, how much activity has it detected?

Dr. Gay:                      Well, Mars is pretty boring. And they haven’t been able to use the seismograph the entire time they’re there because they have a second instrument, the Mole. Didn’t work so well, it was supposed to dig itself under the ground a few meters. It determined that Mars dirt isn’t packed the way it can dig through but, it tried a lot. And when you’re hammering something into the ground, you can’t detect earthquakes, mars quakes, moon quakes, whatever kinda quake, there’s hammering going on, you can’t sense them.

So, during the time the seismograph has been used, they’ve seen a background of quakes that are very similar to the kinds of quakes that we see on the moon from a world just basically settling out over time. But they’ve also caught twice last season and twice this season fairly significant earthquakes greater than magnitude three, you would have been able to feel when you were there. Earthquakes during the northern summer and these earthquakes seem to originate up around a Lucien plateau, which is near where Cerberus Fossae is located.

Fraser:                         And so, a site that seems to be some of the most recent volcanic activity on the surface of Mars. Yeah, I think I’d read that in the last year they detected something like 300 or maybe 500 quakes. So, they’re detecting a quake a day pretty much. And as you said, magnitude two, magnitude three at the most, three point something, three point, yeah, two at the most at. So, nothing that dangerous, nothing’s gonna cause your Mars coffee to spill over.

Dr. Gay:                      And these quakes, they get divided in how they shake, rattle and roll into two basic categories. Quakes that behave very, very much like moon quakes. And those are those background quakes that they see on a regular basis. And then, there’s those two last year to this year earth-like quakes and those are the ones that are really fascinating.

Fraser:                         I’ll bite. I mean, as a resident of the West Coast, I am familiar with the unsettling experience of being in a fairly significant earthquake. So, what is an earth-like quake? How is that different from a moon-like quake?

Dr. Gay:                      So, when we have earth-like quakes it’s usually because there’s some sort of tectonic activity. It doesn’t have to be a moving plate. Iceland gets plenty of earthquakes due to the movement of magma beneath the surface. But essentially what you have is one chunk of planet decides it’s going to bulge out or it’s going to collapse down. And these motions within the rock can set waves moving through the surface and then through the core of the world.

Fraser:                         Right.

Dr. Gay:                      Now, the other thing that you have going on, which we also see on the moon is over time planets in general are just settling like a house is settling. You see things compressing, you see them responding to the constant shake of background meteorites hitting. And this slow settling causes its own background of earthquakes. And there’s nothing really exciting about this, just basically you build anything, you set it down and gravity will cause it to eventually settle into the most compact form it can be. And it takes time.

Fraser:                         I imagined you’ve got a ball of aluminum foil and you crunch it up into a ball as tightly as you can and you give it to someone stronger than you and they crunch it even tighter. And then, use some tool, a hammer to crunch it even tighter and you just got this settling where the objects just getting smaller and smaller and smaller.

Dr. Gay:                      I don’t know if you’ve ever had a precarious pile of things, for me this is usually dishes.

Fraser:                         I believe I have some around me right now.

Dr. Gay:                      Yeah. And they seem to be more or less stable in a Jenga game kind of competitive manner. And all of a sudden, you see nothing obvious going on and they’re like, “And now we’re going to switch to a lower potential.” And things move and this could be there was a breath of air, this could be that there was a tremble in the ground so small you didn’t feel it. And that tiny change to the environment was enough to take something over the edge from static friction holding it in place, to kinetic energy taking over.

Fraser:                         So, when we look at the huge volcanoes on Mars today. We’ve got Olympus Mons and the other three Mons. They’re just absolutely enormous volcanoes bigger than anything else that we know of in the in the solar system. The height is ludicrous. Clearly an enormous amount of material was pouring out of these at one point. When do we think that they died?

Dr. Gay:                      So, those massive, massive volcanoes that clearly look like volcanoes probably died billions of years ago, which is quite sad. But just like we have a variety of different kinds of volcanoes here on Earth, it turns out that Mars had a variety of different kinds of volcanoes there. When we look at the massive shield volcanoes, we can imagine pyroclastic flows going down their sides and everything just building up over time and ash getting shot into the – well escaped velocities with some of those volcanoes.

What we’re looking at with Cerberus Fossae instead is more like the ground open up and lava explosively came out of it, sort of like what we’re seeing happening in Iceland right now. And the ground cracked open and spit lava. This is explosive volcanism. And it leaves a very different marking on the surface and the images that are associated with the most recent volcanoes identified. What you see is this odd dark splotch on the ground, kind of like a pinched off oval and it’s that splotch that is the most recent lava that overlays all the other lava in the region and has so few craters that they appear young.

Fraser:                         And so, then to compare how that all looks to what we’re seeing these features in the Cerberus Fossae. Is that right? Cerberus Fossae?

Dr. Gay:                      Cerberus Fossae. Yeah.

Fraser:                         Yeah. What did those features look like as a comparison of – as I said, we know are clearly ancient volcanoes and now we see some of these more recent. What are we seeing?

Dr. Gay:                      Those are the explosive volcanoes. The ground cracked right here, oozed out a bit, and then, stopped. It didn’t bother to build mountains, it didn’t bother to build enormous structures, there’s just a dark splat across the Mars.

Fraser:                         Right. So, what makes the scientists think that this is fresh-ish?

Dr. Gay:                      So, we get at the age of things on Mars by looking at how they’re layered on top of each other. So, you have for instance, a field of non-duney surface. So, you’re seeing old surface and it’s covered in craters. The more craters you have, the longer that ground has been there exposed to space, waiting for things to crater it. Overlaying on top of this ancient surface, we periodically see things like water features, canyons, valleys, stream beds, ponding, shores, tsunami lines. All these things are on Mars.

We also see layered on top of things, volcanic activity, the tongues of lava that cut across the world. So, by looking at how you have this underlying maximum number of craters terrain. Layered on top of that you have various tongues of lava, streams of material and craters are through all of this. The places that have the smallest number of craters are the youngest. So, when we look at sand dunes that are still sweeping across the world, changing from season to season, those areas have almost no craters at all.

Sometimes they have no craters for the smaller sand dunes. That’s a young place. In this case, we have lava that is inplaced over other lava, has negligible numbers of craters, and everything lines up between what is the age of the material it’s on top of? How much stuff does it have trying to be on top of it? It seems to point to it being just 50,000 years or less.

Fraser:                         And so, if you could have been there whenever it happened, what would you see?  I’m familiar with different versions of volcanoes. I think about what you see in Hawaii with Kilauea, with big blobs of lava pouring down the landscape. I think of things like Mount St. Helens, which are more explosive.

Dr. Gay:                      Yeah, nothing that exciting. So, this would have been the ongoing volcano, currently erupting near Reykjavik, I am not going to attempt to pronounce the volcano’s name. I’m sorry, humans.

Fraser:                         Something “jokall”.

Dr. Gay:                      I don’t hear the sounds well enough to try and make the sounds and I will admit to that. There’s an ongoing eruption near Reykjavik where, basically a section of ground started spewing lava out of it and it’s slowly building up hills, it’s filling up a valley. But it’s never going to become a mountain unless it lasts for longer than anyone can imagine.

Similarly, a few years ago on the Big Island of Hawaii, the volcano there decided it wasn’t going to erupt out of its crater for a while and instead decided to eat a subdivision. And those cracks in the ground that spewed lava and ate people’s backyards and homes. That kind of a cracking, open lava explosively coming out of the ground that again is more the activity that we’re looking for.

Fraser:                         Right. And so, how close could you get and be safe, do you think? Would you wanna be kilometers away from it? Would you wanna be a few 100 meters away from it? Would it be spraying –

Fraser:                         And I wonder how it be behaving? Sorry, I got a million questions.

Dr. Gay:                      Right. So, I respect your million questions. And I love volcanoes.

Fraser:                         I know. I think that you were one geology class away from becoming a geologist and not an astronomer.

Dr. Gay:                      Well, I never took a geology class ever.

Fraser:                         So, if you had taken the geology class early on when you were doing your science degree, you could very well become a volcanologist. I’m just putting that out there.

Dr. Gay:                      So, I think that just like I love biology and animal science, but I recognize that I’m sufficiently dyslexic that I shouldn’t try to take that many chemistry courses.  I suspect that there is enough mineralogy and volcanism that I would have fled. But this is a lesson to all of you, you can be learning disabled and still get a PhD in science. Just know your limits.

Fraser:                         Yeah. So, I guess where this is all coming to is just, how active – if it was 50,000 years ago, that’s fresh. That’s now essentially. So, could there be another eruption on the surface of Mars any day now? Almost inevitably?

Dr. Gay:                      Well, probably not any day now, because the earthquakes would have been much more interesting if something was about to blow. But could there be conceivably another event? I’m gonna go with – I’m not gonna say no to that. And where I took pause and trying to answer all your questions is, I honestly don’t know how the significantly lower gravity and less atmospheric pressure is going to change the safety radius around a volcano. It’s gonna be a whole lot easier for any volcanoes on Mars to fling things in your direction. So, maybe give them a little more space than you’d give the same volcano here on Earth.

But this wasn’t a, “destroys an entire island like Krakatoa” kind of event. And it’s the thing where I can imagine being a couple of Mons away, looking across the valley, and seeing it off in the distance completely safe and edging your way forward. With all of your detectors trying to figure out what are the limitations on this new world.

Fraser:                         We’ll just remember in the 1/3, gravity, any blocks and boulders thrown into the air will travel triple the distance, so.

Dr. Gay:                      This is why you start out a couple mountains away.

Fraser:                         Yeah, start faraway and see what happens. And so, if there was some ongoing or future activity, what do you think InSight would detect? What would it look like?

Dr. Gay:                      So, what has me so excited is it’s not just InSight that could potentially be detecting things. So, inside` if there was suddenly going to be a pressure release in the form of magma oozing forth, you’d see building up earthquakes is essentially the pressure builds, and builds, and builds, just like we see in Iceland and in other places. But in addition to that, you’d see outgassing. And what fascinates me about this and I haven’t been able to find a paper discussing this new enough to take in InSight and Horvath’s work.

We have in the past detected methane during the summer months on Mars.

The two pairs of earthquakes that have been observed have been observed in the summer. And this is consistent with what we see on Earth, where when you release the added pressure of having things frozen, it liberates things to erupt. And so, we’re seeing the summertime release of methane, the summertime quakes, which point to geologic activity that I had been so hopeful was biologic activity in the past. So, now we have even more questions.

We have even more questions. So, now we need to do more work to figure out does TRACE, does MAVEN, do these gas detectors detect gas tied to the seismology?  So, do you see more methane when you see more earthquakes? Or is it different parts of Mars? And these are the things that we now need to start figuring out. The universe loves yes, and. The universe is all about improv.

Fraser:                         Right. Yeah. So, I’m just imagining this idea that you’ve got this volcanic activity that’s pinpointed roughly by InSight and that tells you that some volcanic outgassing probably happened in that region. And so, then you try to target TRACE or some other spacecrafts that’s watching the atmosphere to see if you see a buildup of methane in that region and if you do, sorry life.

Dr. Gay:                      Well so, this is where the yes, and is so important, is I think we need to one, be paying attention to those northern low lands where Lucien Phoenicia and Cerberus Fossae are located, this vast area that’s thought to perhaps be a crater. We need to be paying attention to it to see what methane is there. But then we also need to do controls, go look at the highlands somewhere. Go look someplace absolutely still and see what is it’s methane over time. There’s a lot to understand. And all because there’s geologic methane doesn’t mean there isn’t also biological thing.

Fraser:                         Right. Which is somewhat, I mean exciting but, also frustrating, because we imagine it’s going to be one thing or the other. And then our science will tell us whether it goes one way or the other. But the inevitable possibilities, that it’s a delightful blend of all of them. And as you say, yes, and.  So, is it volcanic activity? Yes. But is it also biological activity? Maybe. We still can’t rule it out. So, yeah.

Dr. Gay:                      Yeah. I wanna say yes. I have no reason to say yes, I wanna say yes.

Fraser:                         Of course, but yeah, but I love that. The answer is always more complicated than you thought and–

Dr. Gay:                      The universe is more creative than we are.

Fraser:                         Yeah, yeah. And so, we go into with these really simplistic ideas and when we walk out with is complicated questions. Right?  And then, we try to get the answers to those. And it turns out that those are complicated questions and so on. We’re never finding answers. We’re just finding better questions. And I think that’s science.

Dr. Gay:                      It’s a wonderful path forward. And we’re just gonna have to yes, and our equations too

Fraser:                         Right. Thanks Pamela.

Dr. Gay:                      Thank you.

Fraser:                         All right. Do you have some names for us this week?

Dr. Gay:                      All right. So, as always we are here thanks to the generous contributions of people like you. You allow us to pay the cat herders and make sure they have medical benefits.

And without Nancy, Beth, Allie, Rich, all those humans behind us, we would not be here for you. So, thank you and this week in particular, I wanna thank Rayvening, Allen M Price, Marek Vydareny, Mark Van Kooy, Ben Floss, Elad Avron, Phillip Walker, Matt Rucker, Joshua Adams, Nate Detwiler, David, Gregory Singleton, Karthik Venkatraman, Chris Scherhaufer, VocalWarrior24, Cooper, Gfour184, Sarah Turnbull, Scott Bieber, Don Mundis, Paul D, Disney, Matt Newbold, Jen Greenwald, Dave Lackey, Lew Zealand. I’m gonna need reading glasses for some of you.

Fraser:                         I love this. This is the best.

Dr. Gay:                      Dean McDaniel, Father Prax, Andrew Stephenson, Kenneth Ryan, Steven Shewalter, Bart Flaherty, Anitusar, Rachel Fry, Cemanski, Tim McMackin, Matthias Heyden, Glenn McDavid, Planetar, Antony Burgess, Shannon Humber, The Air Major. Thank you all.

Fraser:                         Wow.

Dr. Gay.                      Thanks all of you for everything you do.

Fraser:                         Thanks, everyone, and we’ll see you next week.

Dr. Gay:                      Bye-bye.

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