AM: Hello and welcome! My name is Alex Mehta, and I’m one of this year’s Science Communication Interns at Earthscope. Beck and Riley, if you want to introduce yourselves?

BH: Yeah! I’m Beck, I’m also a Science Communication Intern, and we’re here to interview Riley–if you want to introduce yourself.

RZ: Hi, I’m Riley! I’m also an intern. I work on DAS with Chris in the Instrumentation group.

AM: Okay, cool. So today, we’re mostly giving a spotlight to Riley and her background, what she does both within EarthScope and outside of EarthScope. So, Riley, just to start off, do you want to give us a bit of your background? Your career path, how you got to where you are?

RZ: This is actually really interesting. So I got my bachelor’s degree back in China, in the University of Science & Technology of China. I got admitted in 2016 as a math major freshman, and then I got super into outdoor activities, with those clubs, and then they’re like “oh my gosh this is mica, this is so beautiful! Oh my gosh, this is an intrusion!” and I’m like “wow that’s so cool.” So before that I only had a background in math and some programming. I never thought about geophysics. I actually didn’t know that was a major before. But then after going out with the outdoor club I’m like “wow, that is actually so cool.” Your work is so closely related to the major. After my first year I actually talked to a lot of people. I firstly talked to a professor–he worked in penguin poops in Antarctica!–he got me into geophysics and then here I am! It’s fun but I didn’t think about seismology at first, but then when I was in my third year, there was an exchange program. I worked with Sean in Michigan State to deal with this, you know, attenuation tomography, to try to study how the Andes Mountains grow. And now I’m like, “wow, that’s that’s my life goal.” And then after I graduated, I went to Michigan State and work with Sean on seismology and then we did everything, following up. 

BH: That’s really cool. So, can you tell us a little bit more about what exactly you do, measuring the Andes Mountains getting taller? What does that mean?

RZ: That’s actually sad. I’m still working on that. I still haven’t finished it. So we’re trying to study the seismic signals, consisting of three terms. One is the source, the other is when it goes right, when it propagates, it’s like the platform and then when you have a seismometer you record it, but there’s like a slight amplification factor. So, there are like three different terms that can affect the observed signals. We are trying to know about the source term and the earthquakes that happened in the Andes, the flat subduction zone and then after we move that, we will learn about the path turn, how the seismic wave transports through the interior of the Earth, and then we’ll be able to tell. For now we kind of know that it’s a very cold subduction zone and there might be a lot of post ridge deformation on the other side of the Andes but we’re still in progress. I actually spend a lot of time dealing with this math. I don’t want to emphasize that for now.

BH: That’s really cool, you’ll have to keep us updated as that progresses!

RZ: If you–oh, probably not–but if you but there’s somebody called Alissa working in the instrumentation group in EarthScope. She actually works on the same project I’m working on right now. I’m like, “Oh my gosh, the world is so small.”

AM: So, I suppose now that you brought up EarthScope, how did you come across your internship in particular? Had you heard of Earth Scope before? Was this totally new to you?

RZ: Definitely. I’ve definitely heard of it before. But I’m doing seismology. I’m more familiar with IRIS. I know IRIS very well. I downloaded my data from IRIS. I also, like when I first published my paper, I also had to upload my model to EarthScope’s platform. So I know EarthScope as a platform very well, as a user. I did not think about working here before, because I thought that it’ was kind of a little bit far away from my project, but then they’re like recruiting internships. I just got an email from our department chair about it and thought that it was actually cool. So, I applied for DAS and Instrumentation internships. I ended up being an Instrumentation intern but working on DAS. So I’m doing everything I wanted to do before I applied for it.

BH: Sweet. What exactly is DAS? Could you explain that a little bit?

RZ: Sure. DAS is distributed acoustic sensing. It’s kind of like how you have the cable from AT&T, Verizon. They’re like similar cables. They’re buried underground. And there is something called an interrogator. They’re shooting the laser inside the cables and then there might be some little imperfections that can reflect the laser back. While we can always receive the laser signal when it’s reflected back. And if there’s like a very small displacement of the cable or like a little strain, the reflector laser would not be the same as it was before. So based on that, this is kind of like a seismometer. It records how the cables are distorted or like moved. You can understand it as a very, very dense array of seismometers and we also use a seismograph, the seismic signals to deal with the underground imaging or like flooding, irrigation, something like that, all sorts of signals. And you probably remember that Chris has posted the DAS, like so-called seismometers that can also record the signal of the coyote and deer around there. So it’s so cool, they can basically record all sorts of signals and all different frequency bands.

AM: So I guess–and I’m asking this because I’m not as familiar with the work you’re doing– what’s the current application for this? Like what is this data going towards? 

RZ: Generally, we can study animals, some people study insects. Some people even study whales’ behavior. Some people use that to know more about volcanoes and some people use that for underground imaging. What we are trying to do right now is to use a technique called autocorrelation to see the discontinuities beneath the Socorro facility in the instrumentation center. We are trying to see the bedrock depths. We also want to see the same magma body. So there’s like very few studies there. We are trying to see what kind of results we can get. It’s not limited to underground imaging. We still want to know everything about it. They also want to study the current relationship between the depth signal and the temperature, flooding, precipitation, everything. There’s a full potential of depth.  

BH: That’s really cool. What part of the world specifically do you have this array out at? Like where are you trying to learn about? 

RZ: Yeah. So, you probably know the biggest instrumentation center in America is in Socorro, New Mexico. So there’s a Socorro facility. They have a lot of seismometers and a 

warehouse, and they deployed–I’m not sure if it’s 1 kilometer or 2 kilometers–gas and cables just around that warehouse. So it’s very close to New Mexico Tech, in between a lot of mountains. So they want to know the bedrock depth there and they also think there’s magma beneath it? Yes, there’s very few papers talking about it. They use different methods and we guess–not guess–but there are a few papers about it. Their conclusion is that there’s a very thin magma body with something like a 100 meter thickness at the depth of 18 kilometers. We really want to see it but we’re not sure if we’re able to see it. Probably because DAS data is too noisy or we only have one direction of data instead of three directions, three channels. We still don’t know. Also, we’re so lucky that we have four seismometers deployed near the DAS cables. So, our next step is to study autocorrelation with the seismometer data to see if we can observe that. So we don’t know. 

AM: That’s really cool, I’m learning a lot. So, I’ll ask, since even just within EarthScope there’s so much variation even between us interns, what we’re doing. What skills do you think you’ve learned or maybe you think you were going to learn or haven’t learned that you’re finding you’re applying in this internship. Maybe any past skills that you’re using now or anything that you’re learning for the first time now, anything like that?

RZ: I think I’ve turned to a completely different person after like this month. It sounds dramatic, like firstly when I talk about technical details, I did not have experience working with DAS data. This is a more noisy, but much denser array. If you deal with it with more caution, you can get a very high resolution result. So, technically, I’ve gained the skills of DAS data processing, but what’s more important, throughout our orientation, they talk about making connections. I like to actively talk to a lot of people in EarthScope. I feel like everybody is so nice, and they just share everything they can think about with you. And then before that I just thought, “oh yeah I’ll just do my seismology and graduate and be a postdoc and find a tenure-track position.” Then I realized that’s not the only way. I feel like I cannot very specifically see what my career path is, but my career path has been broadened so much since last month, and I’ve gained more confidence talking with people. Yeah, I feel like that’s the most important thing that EarthScope has taught me.  

AM: Okay! We’ll wrap up there. Thanks so much for talking with us, Riley. Beck, thanks for helping me host, and thanks so much for watching!