This summer at Missouri S&T, I will be working with Dr. Kelly Liu to analyze shear wave splitting in order to better understand the structure of the lithosphere below Illinois, Missouri, and Iowa. Analysis of shear wave splitting measurements allow us to probe for anisotropy within the lithosphere which can yield clues about current lithospheric structure and past tectonic history of the region.
Ahhh! Sorry for the absence folks. I mean to deal with this on time (in week five) but alas that didn’t happen. Getting data to check took a long time so once I finally got it, I was pulling 10-12 hour days to get through checking it! So now I’m catching up on this at the dawn of week seven while I wait on the next processing step.
The paper that has laid the best groundwork for what I’ve done this summer is the methodology paper that explain how to make good SWS measurements, but that one can be a little dry despite its incredible usefulness. Instead I’m going to focus on a paper about my region, “Fossil flat-slab subduction beneath the Illinois basin, USA.”(Bedle et al., 2006) Because my region is located in the North American Craton, this is one of the few high resolution studies that focuses specifically on my area of interest. The approach used to study this region was seismic tomography to detect and better resolve previously observed low S-velocity structures in the lithosphere below the Illinois basin, which is the dominant structural formation in my region. The primary take away is that there is a low velocity anomaly at the base of the crust down to 90km depth. This is indicative of hydrated or oceanic crust or a cooler mantle wedge thought to be a result of flat slab subduction during the Proterozoic.
Here is a preliminary map of my study region with my splitting measurements. The angle of the line represents the fast orientation splitting direction while the length represents the splitting time. The different colors are for the different phases used: PKS, SKKS, and SKS. The NE to SW trend of most of the lines is consistent with anisotropy resulting from the motion of the North American Plate. This figure is not particularly clean or well labeled yet as it is a very preliminary generated figure for my data. The scattering of directions at some stations has two causes some variation is caused by complexities in the lithospheric structure and others are just bad data points. My next step is to comb through the “messy” looking stations to ensure that there is just good data being included.
The most frustrating part of my internship so far is the amount of waiting I’ve had to do to even get processed data to start manually checking. The supercomputing cluster at MST this summer has been having some system wide issues which has been causing my runs to fail frequently and run really slowly. This has been challenging because I like to feel like I’m doing something at all times, so I take these computer failures to heart. However, in some ways this is good practice because in research things fail and sometimes you just have to wait. This is difficult for me, when it is something I’m in charge of I have a much easier time taking the failure in stride because I can redouble my efforts and work to fix it. In the case of the computer issues I’ve been having, it is all out of my hands.
This week did have a small victory. I finally started getting some output files for the pks arrival data for the first 70 of ~230 stations. This means I’ve been able to start manual checking some of them and that I have a pretty decent number of good measurements. Being able to make even a tiny amount of progress really turned my week around. It also means I will have at least a little bit to present. I was starting to get worried that everything would have to happen really last minute.
Below is my station map for my region. Every dot is a station with data for events that occurred 84º-180º from my station and had a magnitude greater than 5.6. You can see I’m lucky to have really good coverage for my region, although, that coverage is also part of why this initial data processing is working so slowly. Making this map proved a little tedious. If I waiting to let my data processing finish, then I would be able to automatically pull out a list with all of the station locations on it. However, because that is still running, I had to compile a list of all of the stations I had gotten data for through our automated requesting process and then search them on the IRIS website to get their locations and compile my list of locations by hand. Once I did that importing the data into Matlab and plotting it up was a breeze. I am forever grateful for Matlab’s great documentation. Eventually, I will make a nicer map in GMT, but I’m working my lab computer pretty heavily right now. Given how finnicky things are being, I’d rather leave it to run the stuff it is already working on.
I’m once again posting a little late, but I took a last-minute trip back to Wisconsin this weekend to see my sisters, so here we are. In terms of my work so far. I have yet to get to do anything particularly hands on with my data yet, I’m still waiting for the initial automatic processing to finish up. I’m starting to get a little antsy for when I can really start digging in.
Being in a position where I haven’t gotten to spend that much time with my data yet had a lot of influence on my elevator pitch it ended up. In some ways, it made writing my pitch easier in that it is hard to write something too long if you don’t have many details yet, but it also meant that the impact of or take away from what I’m working on this summer was difficult to convey because I don’t have even a preliminary idea of if my measurements in my region will turn out to be any good.
Something else I reflected on while working through my elevator pitch is the importance of audience. In the end, I have more like three elevator pitches. The information one needs to include varies so much depending to whom you are talking. I see it as a pitch for seismologists, a pitch for non-seismologist Earth scientists, and the pitch for family/friends/people completely outside the field. I think remembering that is super important because even at AGU there are plenty of people who wander by posters completely outside their own discipline. In addition, as a rising senior, I’m starting to look beyond undergraduate life and look at post grad options. Having a concise way to describe your research experiences ends up being truly invaluable.
Week two is coming to a close. EDIT: It fully closed, but I got too distracted by the USWNT Quarter-final match to remember to hit post. This week definitely felt more productive than last week (I was definitely less jet lagged.) Although, I’m still very much at the mercy of my computer. For my work this summer, the first step is letting the computer automatically process and rank all of my data. So while I have been letting that happen, I’ve continued to brush up on background papers and bolster my GMT skills.
This waiting game to move on to the manual checking stage also gave me time to really reflect on the skills self-reflection that I went over with my mentor this week. While I don’t know if this reflection really taught me anything new about myself, it was a good tool to allow me to share with my mentor where I felt I was at. Because I am mainly running automated processes so far, I haven’t had a ton of cause to ask my mentor lots of questions. This exercise gave me the chance to elaborate more on my experiences to date and how I think they will inform my work this summer.
The data set I’m using can be described on multiple levels. Most fundamentally, I am using the waveforms from events which were detected by the seismometers in my region. However, that pretty quickly (or as quickly as the data processing goes) that gets turned over into measurements of splitting times. That will be the data set from which larger interpretations will be made.
I have finally arrived in Missouri after traveling a bunch for a field course at my home institution. I started out this week excited, albeit very tired and jetlagged, to hit the ground running on my project! Unfortunately, the computers I was working with didn’t have the same idea. Shout out to the other intern at my site, Paige, for getting a lot of this hiccups worked out in previous week. As of today, I’m finally getting my data!
Throughout the summer one of my major goals is to get a better feel for seismology as a field in order to understand what directions I may want to take for graduate school in the future. To do this, I need to make sure I am doing the work in order to understand my project, but also to understand topics more tangentially related to my topic as well. To achieve this, I want to make sure I’m reading at least two papers a week on some aspect of my topic, whether it is discussions on shear wave splitting methodology or more about regional observations for my location of study.
Another thing I want to do is use this summer, because there is more down time, is to hone my scientific communication. In the first third of the summer, this will take the form of making sure I am adept at describing my project to a variety of audience. I plan to be better about writing brief daily and weekly research updated just for my own purposes. That is something I haven’t always been the most diligent about in the past but makes writing later on much easier. In the second third of the summer, focusing my energy on writing a strong AGU abstract will improve my skills. Hopefully, by then writing updates for myself will be a habit. By the end of my summer I want to make sure I have at least the bones of my AGU poster all finished up. This will help my share my work and will save me some stress this fall if it is mostly done.
My personal goals for this summer are less concrete. I am largely looking forward to being here is Rolla, away from my usual school and work commitments, so that I will have more time to relax and focus on self-reflection as opposed to always having to move on to the next thing. A break from my usual over scheduled life will be good for me as I am about to enter my final year of college, but also likely pose some challenges. In furthering this goal, I’m really lucky that I’m adjacent to so much natural beauty this summer! I’m looking forward to spending my weekends hiking and maybe even fitting in some short camping trips.