This summer, I will invert seismic data to construct a phase velocity map of Africa. When any "source" causes the ground to move (think: earthquakes), energy is released. This energy then travels through the ground as seismic waves, which can be recorded by a "receiver" (think: seismometer) at another location. If we know where the source and receiver are, then we know how far the seismic wave traveled. Furthermore, if we know when the source released energy and when the wave reached the receiver, we know how much time the wave took to travel. With this distance and travel time, we can estimate how fast the wave traveled. To seismologists, these velocities are especially interesting, as they depend on the material through which seismic waves travel. As such, knowing the velocities through Earth can clue us into what compose our planet! On a smaller scale, seismologists use inversion find the seismic velocities through a particular region. We first collect many records of seismic waves, all of which travel throughout that region. Next, we create a series of models, each assigning different velocities to different parts of that region, and see how well those models are consistent with our data. Our goal is to find the models that are most consistent. Using inversion, I will construct those maps for Africa, showing how fast seismic waves travel across the continent. Specifically, I will use a relatively new method called "Bayesian inversion." I will then analyze my resulting maps by comparing them to one another and to those of previous studies, so stay tuned! (P.S. For more on seismology, see Introduction to Seismology by Peter M. Shearer, and for inversion, see Bodin and Sambridge, 2009; and Olugboji et al., 2017)
This week, I have been asked to construct an elevator speech about my project. In case you are not familiar, an elevator speech is a brief, 30-60 second overview of my research, describing what I am doing and why my project is significant. Moreover, these speeches are geared towards audiences new to my project, or even geophysics itself. The goal is to get the attention of as many people as possible, so that they would be interested in hearing more about my research.
Constructing my elevator speech was pretty challenging. I have done similar exercises before. Namely, for past research internships, I prepared talks about my work geared towards an audience unfamiliar with my field. However, while those talks were ~10 minutes long, my elevator speech is much shorter. Knowing which details to include or not include became very important. As I composed my speech, I asked myself repeatedly: "What do I need to say to ensure a coherent 'story'?" Narrowing down the right details and explanations was definitely difficult. After composing a few drafts, I practiced my speech to my friends and family, and received constructive feedback.
Though challenging, I am glad to have had this experience. After all, successfully building elevator speeches will be a crucial part of my career. As a researcher, I will spend a significant amount of time at conferences, presenting and discussing my work with fellow scientists. Often, I may be presenting to people outside of my field. As such, my presentation cannot be filled with excess technical terms or jargon. What I say might be understood by a fellow seismologist, but not necessarily to an oceanographer or a geobiologist. If my presentation is not clear to everyone or if it does not get others' attention, then that defeats the purpose of presenting! By constructing elevator speeches, I practice tailoring my presentations appropriately to my audience.
I will update and polish my elevator speech as my internship progresses. I am very excited to present it at AGU this fall (and hopefully other conferences!), as well as to my classmates, professors, and research group back at Princeton.
Wow, I can't believe it's already my third week. Time certainly flies! This week, I have been asked to share with you (a) a description of the data I will use for my project and (b) a reflection on a research skill I intend to build.
(a) My project data
As you read in my project description, my objective is to build tomographic maps, showing the velocities of surface waves across Africa. To construct these maps, I will be using records of surface waves, collected by seismometers throughout the continent. I, however, will not be seeing these records directly. Instead, another student researcher in my group is processing these data. She works with these stations in pairs, and for each pair, she isolates the surface waves of interest and derives how fast they travel from one station to the next. Her results will be passed along to me. Then, using the locations of these stations, I will reconstruct how fast those surface waves travel across the continent -- and voila: a tomographic map!
(b) Some self-reflection
At the start of our summer, IRIS provided us interns with a mentoring rubric, a checklist describing a series of research-related skills. This rubric has been very helpful in reflecting my internship experiences. After all, as you read in my first blog post, I aspire to grow more as a research scientist.
In particular, two goals I am pursuing are developing a better understanding of and taking greater leadership roles in my project. How successful I am with these goals is contingent upon how well I understand my research. This understanding, in turn, depends on understanding the relevant scientific literature and my project's place within it. That said, two of the mentoring rubric's skills are especially important for me: "Explain how my research project will contribute something new to existing knowledge" and "Identify and use a range of relevant bibliographic and virtual sources related to my research." In short, fulfilling these goals means being able to explain why my project matters, in the context of what has been done in seismology. These skills are critical, to say the least, as the key of meaningful research is to produce something new --- whether that is a new finding or a new method for data collection or analysis. After all, if a project has been done before, it would not be very worthwhile for the academic community to read, or even hear about at a conference! By all means, those rubric skills are contingent to my career as a scientist, so I aim to develop these as much as I can.
To do so, I am taking several steps. For one, I set aside time to search and read scientific papers relevant to my project. To find sources from reliable, academic publishers, I input key words related to my project, such as "Africa tomography" into Google Scholar. I then read each paper carefully, annotating as I go along. I also keep notes about key points, such as how that project differs from my own. What is not addressed by that research, that my project can address? What is something new that my project can contribute? Thanks to a notetaking sheet provided by IRIS, I have been able to organize my notes so that I can easily refer to them later. In addition to the paper's contents, I also keep track of its bibliographic information using a citation manager. Citation managers have been extremely useful when I need to cite papers, especially well after I read them. So, I anticipate this resource will be very helpful as I construct my AGU poster!
As discussed in my project description, my project centers around tomography, the branch of seismology using inversion to derive a region's seismic velocities. As an aspiring seismologist, I am excited and honored to pursue this research and grow as a scientist! In particular, I am looking to build the following skills this summer:
1. Gain experience with and better my understanding of tomography
Though I am very fortunate to have had experience in seismology research, I have not yet pursued a project focused on tomography. As such, I am very eager to dive into this project! By the end of summer, I will have (hopefully!) constructed and analyzed tomographic maps of Africa. As I work towards this objective, I hope to build a more solid understanding of my project, as well as tomography in general. More concretely, my goal is to be able to answer questions about my project --- such as its background, methods, and significance to seismology --- in a clearer, more confident way. Discussing my project with my mentor, research group, and fellow interns, will let me measure how far my understanding progressed. Having a thorough understanding of my project becomes especially important when I present it, whether it is at a research group meeting, a scientific conference, or through a publication. Presenting my work is a crucial part of being a scientist, so I am eager to improve as much as possible.
2. Take a greater leadership role in my project.
As the summer progresses, I also aim to take increasingly greater leadership roles in my project. This goal is of particular interest to me, as it is relevant to my career development as a researcher. As I progress through this path, I will take more ownership over my work and have greater agency in deciding where to go next --- which methods to use, how to analyze my results, which research questions to answer, etc. This internship, where I will work closely with a research question, will be the perfect environment to start building this skill. By the latter half of my summer, I aim to take more initiative in proposing the directions of my research, especially compared to now.
3. Improve my programming skills
Through my previous research experiences, I gained experience in programming languages important for seismology. For example, I learned how to use MATLAB and Seismic Analysis Code (SAC) to process seismic data. However, there is always room for improvement. For example, there are programming tools out there that I have not yet used, but will learn through this internship. Right now, I am learning how to use rj-TOMO, a software designed for performing inversions on seismic data. I am operating this code on problems using synthetic, as opposed to real, data and writing programs to visualize these results. I aim to learn how to use these programs on real data soon! Moreover, I look forward to furthering my experience with programming languages, such as Python and MATLAB, and growing as a programmer.
I will be sharing more of my progress as the weeks go by. Stay tuned!