“There’s always been this idea that my family has a relationship with the bones of the Earth,” says Kevin Mendoza.

The graduate student in the Department of Geology & Geophysics descended from the developers of the Nacia mine in Chihuahua Province. He recalls as a child his grandmother showing him jars of rocks from the mine given to her by her father, one of the only possessions she took with her when she immigrated to the states. A Ph.D. candidate in geophysics, Mendoza is the recipient of the 2023 University of Utah Teaching Assistantship Award: Pythonizing Geoscience Instruction. Mendoza received the award for his contributions to geoscience undergraduates. He used the assistantship to develop python programming-based core curriculum.

Mendoza joined the U after attending the University of California, Merced for his undergraduate degree where he double-majored in physics and Earth systems science. His passion for studying the deep Earth came both from his early geology lessons with his grandmother, as well as the active outdoor lifestyle his dad cultivated in him from an early age. “It was rare for any of my classmates to like even the more accessible activities like hiking, and for the Latinx students such as myself, [it was] completely unheard of at that time. I’m grateful both my parents encouraged exploration of what was then an unconventional hobby.” In high school, Mendoza was particularly passionate about gold prospecting, which he did almost every weekend in the nearby San Gabriel Mountains. He continued his wilderness ramblings in the Sierra as a park ranger in Yosemite National Park during college.

Magnetotellurics

Although his ancestors have been students of the Earth for generations, Mendoza is the first in his family to study it academically. His background prepared him to do a different type of prospecting: for electrical fields within the Earth. His research under the late Philip Wanamaker operates in the niche field of magnetotellurics (MT), which uses natural underground electrical currents to study the structure of the Earth. MT is such a specific subfield of geophysics that there are only a handful of programs across the country, including at the U. “What I do is use solar wind and lightning to basically CT scan the deep Earth,” summarizes Mendoza. From the results of this “CT scan” he can measure the water contained in the geologic water cycle, which has important consequences for plate tectonics. One of the advantages of MT is that it is more sensitive than other techniques such as seismology. “In some situations, like looking for critical battery metals and hidden geothermal resources, MT is one of the best methods for exploring mineral structures.”

Mendoza’s data comes from monitoring the voltage and magnetic field in the deep Earth with sensors deployed on the surface. In the field, these sensors are set up by placing magnetic coils and wires stretching along cardinal directions, and occasionally a coil pointing upwards. These sites are left to collect data for a few months at a time before they are relocated. Since the equipment is portable and non-invasive, MT sites are placed virtually anywhere that’s interesting geologically.

One of the main challenges with MT is visualizing the high dimensionality of the data. While common to other fields, like data science and machine learning, it takes on a unique flavor within MT. Each MT station produces nearly four times more data dimensions than seismic stations do. Complex mathematics are needed to transform this data to usable geologic models. One of the models that Mendoza works with uses over 2.5 million parameters. Analyzing the data and models is only possible using cutting-edge supercomputing tools. As part of his dissertation, Mendoza plans to provide a massive Python codebase that will help other researchers explore similar datasets.

Putting carbon back underground

While his dissertation is focused on more fundamental aspects of plate tectonics across the western U.S., Mendoza believes these findings can have application elsewhere. “Two of the biggest challenges we face with climate change are how to transition to a carbon-free economy and how to put carbon back underground. The tools I’ve developed and am developing can directly help these efforts by monitoring how stable our sequestered carbon is, or assessing the likelihood that critical metals like copper, cobalt, and lithium are in rocks hidden by deep sediment cover. These efforts require the same 2D, 3D, and 4D geophysical modeling, visualization, and evaluation techniques I’m currently using in my own research.”

That codebase will also be helpful for industry, which is possibly the endgame for Mendoza.  Having briefly worked as a geotechnician after graduating with his bachelor’s, he understands that a career in academia is not a realistic or desirable path for every student. “My personal philosophy is that universities are hybrids between a job training program and a liberal education. So, we can’t just teach students general critical thinking; we also have a moral obligation to give them some tools so that they can come into the workforce ready.”

Mendoza knows from firsthand experience that mastering the science is only half the battle for many students from underrepresented backgrounds. He grew up in East LA where he learned how to reach across cultural divides from his Hispanic background to connect with others. “Learning to ‘go-between’ is a skill that’s essential for just having a community, and I think bringing that here made it really easy for me to understand when students are struggling,” Mendoza says. He asks himself questions like, How do you reach out to a student who’s not responding in a normal way? How do you make geology instruction more accessible? How do you engage students in the coursework? With this approach to teaching, Mendoza is able to connect with his students to enhance their experience and has earned multiple prior teaching awards in the process, including the National Association of Geoscience Teachers Outstanding TA Award, 2022.

Hidden curriculum

The obstacles for underrepresented students in academia don’t end after earning a bachelor’s; they just aren’t widely discussed. On top of regular classwork, first generation graduate students have to tackle the “hidden curriculum” within academia. This includes issues such as figuring out how to write a dissertation, what the college’s practices are, how to handle advisor conflict and other difficult-to-ask (and -answer) questions.

The overarching difficulty is determining what graduate school is supposed to look like in the first place, which Mendoza says is almost by design. “Grad school is very heterogeneous. Part of that is good because science looks different across disciplines, but that is [also] confusing for first gen grad students who don’t know how to navigate this unknown academic culture.” It’s a problem that is systemic, and not unique to the U.

To succeed in grad school, he says, “you can’t use the old paradigm, pushing boundaries like you did in undergrad and high school won’t necessarily result in the same success as a grad student. The cultural setting is different.” Even outside of academia, underrepresented scientists face many of these challenges. According to Mendoza, geoscience is the least diverse subfield of STEM. Nature Geoscience reported that the last 40 years has seen zero progress with respect to minority representation within geoscience. The United States Geological Survey has the poorest track record of minority employees of all the federal government agencies and is nearly half as diverse as the next ranked federal agency. The lack of diversity is mostly due to the niche nature of the discipline. Unlike, for example, computer science, there is a relatively finite employment pool. 

Kevin Mendoza has come a long way since his geology lessons with his grandmother’s Chihuahuan rocks, and it has informed the legacy he is now leaving with students familiar with the challenges he has faced. The teaching award is an acknowledgement that the paradigm can shift, that the Earth can move.

By Lauren Wigod
Science Writer Intern