Sharan Shreedharan

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This transcript is based on a video-recorded interview deposited at MarE3, JAMSTEC (Yokosuka, Japan).

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Interview of Sharan Shreedharan by Beatriz Martinez-Rius on 2024 November 18, D/V Chikyu (Japan). [link]

Beatriz Martinez-Rius (BMR): Today is 18 of November of 2024. I’m Beatriz Martinez-Rius, from JAMSTEC, onboard Chikyu, IODP Expedition 405. First of all, can you tell me your name, your affiliation and your current position?

Srisharan Shreedharan (SS): Srisharan, I am an assistant professor of geosciences, geophysics, at Utah State University. That’s my affiliation and my current position.

BMR: What are your research interests?

SS: Faulting and earthquake mechanics. Mainly, I’m interested in how earthquakes form or how earthquakes start, propagate, stop in different fault zones. I guess, why and how earthquakes behave in the ways that they do. That could go from really small earthquakes to large earthquakes, or really slow earthquakes to faster earthquakes, and things like that. So, any movement on a fault zone, essentially, is what I’m kind of interested in studying. And I do that through a combination of mostly lab experiments, but also, more and more recently, I’ve been incorporating some numerical modeling work in my research, and in my research portfolio.

BMR: How did you get interested in earthquakes?

SS: When I started working on earthquakes, maybe that wasn’t really, let’s say… I didn’t go and being like, “Oh, yeah. Wow. Earthquakes. This is what I wanted to do”. More so, I think I was interested specifically in rock deformation. I’ve always been interested – a combination of, let’s say, interested and good at – statics and mechanics. My undergraduate and my master’s work is in geological engineering. And so, a lot of times, that included the study of rock deformation: how rocks break or don’t break, and how they deform in a non-brittle way, or don’t deform. So, I was applying those skills to the study of things like slope stability, road cuts… Tunnels and things like that. So, extremely engineering problems. And I kind of, honestly, for lack of a better word, I got bored of it, because it felt a lot like doing the same thing over and over again.

Then, I kind of accidentally stumbled on this whole other world of geosciences, where you’re doing more fundamental research rather than applying it to this tunnel here, that tunnel there. Instead, you’re just doing super fundamental research on taking or squishing rocks and saying something about earthquakes. And I thought that was kind of cool. So, that’s kind of how I stumbled into it, because I didn’t maybe want to re-learn new tools. I just wanted to reapply these tools to new things, if that makes sense. That’s how I accidentally found my way into the geosciences, into earthquake mechanics for my PhD. And I’ve just kind of continued hopping around, ever since.

BMR: It’s kind of a pathway, because you mentioned that you started in engineering. So, let me go a little bit back in time to track this path. First thing is, where are you from? In which kind of environment did you grow up, and what did your parents do for a living?

SS: I’m from India. I grew up in India. I came to the US for grad school, for my masters, and kind of have stayed here ever since. My parents, both have undergraduate degrees, not in science or engineering. I think more like – I’m trying to remember now. I want to say economics, business administration, that kind of stuff. And or, psychology. So, no physical sciences or engineering background. That was just something that I almost feel like – well, for my undergrad, I didn’t choose engineering because I was super passionate about it or whatever. It was just what was expected of you, I guess. It’s just like, if you want to make money, you become an engineer or a doctor or something like that, right? So, I was like, “okay, whatever”. I didn’t think too much of it, maybe.

BMR: So, there’s people that has an early interest in the field, in a scientific career, or something like this. But in your case, you just came through engineering and from there, you understood that there was something kind of exciting in getting into scientific research.

SS: Yeah, that’s exactly right. I mean, I was interested in math and physics from an early age. Not specifically as applied to things, but it was just something that I was both interested in, and I was reasonably good at it. Which, the same cannot be said for chemistry or biology. So, it was like kept going in the direction of math and physics. It wasn’t necessarily an interest. It was more just like, “Okay, I’m good at these two things. How and where can I apply them?”. Getting a bachelor’s in math or physics necessarily was not, perhaps at that time, the best thing for me. But instead, engineering was sort of the next best thing where you get to do both. And since then, I think, until maybe a few years ago, I’ve just been stumbling from one accidental interest to another, pretty much (laughs). 

BMR: May I ask you, why did you move to the US to continue with your master studies? Is this something common, in India?

SS: Well, I guess there’s two parts to that question, right? It sounds like, why masters and why the US for my masters? Why a masters – I think that with just a bachelor in some fields, some countries, and some combination of the two, you kind of have a hard ceiling in terms of your career progression really quickly, without maybe more expertise or more qualifications. And so that’s why that’s why Masters pretty much.

And why the US – why not? (laughs). I don’t know, no specific reason. I’m struggling to remember now, but I am quite confident that I probably applied to multiple different countries and maybe that’s the one that stuck. I really would have to go back and check that, but I don’t think there was any like, passion for America or the Statue of Liberty or something like that. It was just like it just happened.

BMR: I was asking because, I don’t know, maybe you told me that in India, if you want to get a masters or a PhD, it’s pretty common to go to the US.

SS: Not necessarily. There’s obviously lots of master’s programs in India. I could have stayed if I wanted to, I suppose. Maybe it’s not surprising to you either, but the US generally does present a lot of opportunities in terms of, the number of top 50, top 100 universities per square kilometer probably is higher in the US than elsewhere. So, yeah, I think it’s just one of those things where you throw a bunch of darts, see what sticks, and in this case, that’s what stuck.

BMR: How did you cross paths with scientific ocean drilling?

SS: When I was doing my PhD at Penn State – first, that department, the geosciences department at Penn State itself, had a pretty, and probably continues to have, a pretty big ocean drilling footprint. In terms of multiple PIs, multiple professors, having sailed; or multiple students having sailed. I’m pretty sure in the five years I was there, every year there would be at least one professor or one student or more sailing on some expedition. It had a pretty strong presence that way so that, you know, you cannot graduate from Penn State Geosciences without at least having heard the word scientific ocean drilling.

But, more specifically, one of my supervisory committee members for my PhD, Damian Safer, is a big name in scientific ocean drilling, right? He’s done a lot of expeditions as science party member, co-chief, etc. And he’s like one of the big proponents of the NanTroSEIZE project, and so on. So, it just so happened that the Hikurangi Margin Expedition, expedition 372, 375, was happening during my PhD at Penn State, and he was the co-chief for one of the two windows. And so, I was just honestly curious. I don’t even think I ever went and talked to him about it, either. I just kind of like, “What’s the worst that could happen? I get to spend two months on a drill ship. Okay, this sounds pretty cool. And it looks like this would end up being some data sets that I could potentially utilize for my own research,” and things like that. And scientific ocean drilling also provided the opportunity to apply for these year-long graduate fellowships, which is the Schlanger Ocean Discovery Fellowship. And that’s one of a very, very, very few awards of that sort that are available to non-U.S. citizen graduate students. And so, it was just like this confluence of multiple different things that made me feel, “Okay. I should apply and see how it goes”. I did. And that completely… I feel like that expedition blew up my social network within the field, and probably grew my visibility like ten, twenty-fold. It was pretty great.

BMR: May I ask you again what was your PhD about? Earthquake research in fault zones?

SS: Yeah. My PhD was about experimental rock deformation or earthquake mechanics.

BMR: Can you tell me about your first impression of being on board the scientific drilling ship? Was there something remarkable that sticks in your mind?

SS: Yes. I guess both the JR [JOIDES Resolution] and the Chikyu – even though the JR is maybe two thirds the size of the Chikyu – the first thing is just a combination of this massive derrick in the middle of the ship. Like, the ship is taller vertically than it is horizontally, which is just like, wow (laughs), how are you still floating? But also, I think just the engineering, all the machinery, all these massive instruments and machines that are working together in tandem to make this happen. I think it’s just the combination of all of those things, by drilling to the seafloor and beyond. It’s like you’re threading a needle from standing at the top of a building and the needle is essentially on the ground floor. It’s completely insane. I think that the engineering capabilities that make these types of expeditions happen was, to me, the coolest thing I think I’ve seen across expeditions. And that is something you probably never get bored of.

I think, early on, one of the things that happened during the Hikurangi expedition too, is the borehole reentry. So, they throw this big cone at the bottom of the seafloor, once you’ve drilled a hole, because you want to go back to that hole. And the fact that that’s all it took, this black and white painted big, big cone. and then you go back there and plop, you reenter that hole. It just blows your mind, when you see that happen.

BMR: Yes, it’s so impressive. And we are looking at it through the screens, the underwater TV camera. And it’s so clear, the hole, but it’s so far down into the water…

SS: Exactly.

BMR: So, how your research continued in relation to scientific ocean drilling, after that first expedition? Specially in terms of collaborations.

SS: Obviously you’re not going to be in touch with every single person you sailed with, right? You kind of end up evolving into your own niche, or subdiscipline. And these are people that you interact with at multiple conferences throughout the year, for example, and you develop pretty close relationships with them, because you were locked up in the middle of nowhere, on a floating piece of metal for two months. So, you do keep meeting each other, and then of course, you do your work. You present at conferences, publish papers related to the work…. A lot of times they’re going to continue to be coauthors.

In the case of the Hikurangi Margin Expedition, for example, I was running some experiments, start a conversation with Matt Ikari, and he was like, “Hey, I can run some more experiments in the same boundary conditions”. So, he ran some experiments; we wrote a paper together. And so, these types of relationships just organically grow.

BMR: And why did you apply for JTRACK?

SS: A few reasons. One, I was just like, “This might just be the last time to get in an expedition, so let’s get on it” (laughs), and it’s actually relevant to earthquakes. Most IODP expeditions tend to be somewhere on the spectrum of paleo-climate, and far fewer are exploring earthquake hazards at subduction zones. And so, since Hikurangi, I think this might have been the first one, not including Covid, that went back to a subduction zone to look at earthquake hazards. And of course, the Tohoku earthquake is so globally relevant, even if that is not the geographic region you are interested in the context of earthquakes, right?

So, yeah, those reasons. Plus, I was just trying to maybe broaden my research portfolio in terms of thinking about other subduction zones, and not just stay in New Zealand. It was this a combination of all of these things that led me to apply to JTRACK.

BMR: And why do you think your application was selected?

SS:Oh, boy… Jamie [Kirkpatrick] is downstairs. Maybe you should go ask him why did you pick me? (both laugh)

BMR: I like to listen from you, the onboard researchers, because I think it’s a way to make you reflect on the strength of your application, or maybe now, within the group of people you are working, you see some connections that make you realize how your proposal fit well within the science party.

SS: I think that, at least in the past two or three years, one of the big research thrusts that I have been going after is this concept called healing. Fault healing, fault re-strengthening. So, between earthquakes, fault zones have to kind of mate or weld together and regain some strength, so that that strength can be lost again during another future earthquake. This process of healing is what I’ve been studying, and published a few papers recently on healing in the context of the Hikurangi margin.

Then, of course, this idea of healing and re-strengthening is a huge, important, question that JTRACK is trying to address, because it has such a unique ability to tackle this question. Given that JFAST happened, and we’re coming back for JTRACK, twelve years have passed since the earthquake. So, how has the fault zone changed? Has it? Maybe the combination of the fact that they want to study healing – I mean, the co-chiefs—, and that is something that I’ve been interested in, probably helped.

Of course, there’s other people doing friction, or interested in doing friction on this expedition. I think it helps to have multiple people trying to tackle this problem from, even if it is slightly different, but also extremely different, angles. So, maybe I was one of the different angles. That’s probably what I brought to the table.

BMR: You have been on board a scientific drillship twice. Besides the difference on the ship, is there any other difference you perceive, between the first time you were on board and the second time?

SS: Do you mean in terms of how the expedition is being run, or in terms of my own job responsibilities?

BMR: I was thinking more in terms of your responsibilities, your role…

SS: I guess one major difference is the fact that this is a repeat survey, right? So, there is a lot of, let’s say historical – I say historical, but ten, twelve years – knowledge base that this expedition builds up on, which wasn’t the case in the other expedition. That is, obviously, amazing. It’s really useful. Other than that, I would say that I was in the physical properties station at the other expedition, too. I’m in the physical property station here, as well.

Equipment is slightly different, but generally I feel like I know what I’m doing, so that’s not super, super, different. On the other expedition, I’m pretty sure I was the youngest member of the science party, and I was just going around not knowing what I was doing. I was too scared to contribute to the scientific discussions, and things like that. Whereas here, in some ways, I’m just like, “Oh, yeah, I know exactly what I’m doing”. So, even in terms of shipboard duties, that comes a little bit more naturally, more organically; but also, I feel a lot more in my zone to be able to contribute something intellectual to science conversation, within the context of earthquake hazards. Those are probably some of the bigger differences.

BMR: That’s cool. Do you feel that you have grown as a scientist?

SS: I’ve memorized more pieces of literature (laughs). No, but I would hope so. Then I was an early to mid-PhD student, and now I’m advising PhD students. So, in that sense, yeah, hopefully I have grown. But that doesn’t mean that I know a whole lot more than I did then. If anything, I know what I don’t know better than I did back then.

BMR: That’s a good answer. Let’s talk specifically about this expedition. What are the things that, so far, you kind of value or enjoy the most? And the most challenging parts? You can approach these as you prefer, in the personal or the work.

SS: I think the enjoyable part is probably seeing different pieces of science, which are apparently unrelated, come together in these site reports, or in daily conversations and weekly meetings. For example, yesterday I was talking to one of the sedimentologists about how they are distinguishing different depth intervals as unit boundaries, which is something we need to do. And obviously, when the sedimentology or the lithology group do it, they do it independent of the physical property measurements that we’re making. But it was really cool to see that if I had to pick intervals or differences – like, this material is different from this –, I would have probably picked the exact same ones that they did, coming from completely different techniques, let’s say. Some of those discussions are really cool.

In terms of what’s challenging, I think probably the somewhat unique nature of this expedition, having two windows of scientists, and crossing over with people who are here for close to 60 days already; and being thrown right in the middle of the work. That was pretty challenging.  But I think that, obviously, is not just for me, it’s for everyone else who had to experience it. So, would I rather have frontloaded all the work and let it go to zero? Which is what’s happening now – or rather had started at zero and let it ramp up? Who knows. But yeah, that’s been a little challenging. I’m still hoping that in one of these few days I’ll get a full 12 hours of sleep so I can do like a hard reset to my body (laughs). But we’ll see.

Left, celebrating Sharan’s and Hinako’s birthay during expedition 405, on Chikyu. Right, Sharan featured a comic by artist Nur Shuba. Photos by Beatriz Martinez-Rius (left) and Srisharan Shreedharan (right), JAMSTEC/IODP.

BMR: I’m sure it will arrive.

SS: Hopefully!

BMR: So, now that you are at the top end of your early career, so to speak, what has been the most valuable part of participating in IODP, during this first part of your scientific pathway? In which ways has it contributed to that?

SS: In a couple of ways. I’m sure there’s more ways, but a couple of important ways. One is, your scientific social network is so incredibly important for a variety of reasons, to build some of these relationships because the same 5 to 100 people, 50 people, whatever, are going to be your collaborators, reviewing your papers, reviewing your proposals, meeting you at conferences, having discussions… You are part of this relatively small cohort of people who are pushing at the frontier of the science. So, getting to know them on a personal level, growing that network rather than working in your own research silo, has been one of the key opportunities that IODP expeditions in general, but also these two expeditions in particular, have afforded me.

A second thing is more… Even though I may have stumbled into earthquake science, a big part of why I continue to do this is because it’s one of those things where it feels like you are meaningfully contributing to society in some ways. It may not be immediately tangible to the average person, but would they be better off if none of this happened? Probably not. I live in one of the most earthquake hazardous areas in the US. And so, yeah, I think being able to contribute meaningfully to some of these discussions, and hopefully, potentially sort of improving society, one small region at a time, I think that part of doing science is really meaningful to me.

BMR: And do you feel that you arrive to that contribution specially through scientific ocean drilling, more than in other communities or programs?

SS: Yes, absolutely. I would say so, because in scientific ocean drilling, I’m literally – my n equals two sample size, the first one was like, New Zealand earthquake hazard. And now it’s like, Japan earthquake hazard. So yes, there is a direct connection in both cases. Obviously, it’s not just me, I’m like not a one man army who’s going around writing papers, but this entire cooperative or consortium is making that possible not just for me, but for other scientists, as well. And so that’s really meaningful for me.

BMR: Another question is what are your intentions for the future about being involved in scientific ocean drilling? What would you like to see as future of scientific ocean drilling?

SS: I hope it continues in some way, shape or form. There’s still a whole lot that we don’t know about plate boundaries, where some of the most catastrophic earthquakes can happen. There is a huge amount of incentives, both social and economic, to keep things like this going. I’m coming at this from the perspective of earthquake hazards, but also scientific ocean drilling has made so many meaningful contributions in a lot of other ways… This is just the niche that I’m comfortable talking about. But yeah, I hope it continues. And assuming it does, I think my own goal would be to amplify my students, and improve or increase their ability to go on some of these expeditions so that they can start building their own networks, and build their legacy. That’s generally where I’m hoping things will go, but we’ll see how things go.

BMR: Is there something I have not asked you about, that you want to add?

SS: Probably not.

BMR: Well, thank you very much.

SS: Thank you, this was super fun.