Hello! I am

Riley Finnegan

I'm a


About Me

I'm a third-year PhD student in the Department of Geology and Geophysics at the University of Utah. I study the ways humans impact rock arches and towers. I love doughnuts, sunflowers, and red rocks, so Utah is a great place to be!

  • Name: Riley Finnegan
  • Address: University of Utah
    Department of Geology and Geophysics
    115 S 1460 E, Room 383,
    Salt Lake City, UT 84112
  • Email: riley.finnegan@utah.edu
  • Phone: 541-292-7768



PhD in Geophysics

(in progress)

University of Utah

Department of Geology and Geophysics

Thesis: Anthropogenic induced resonance and vibration fatigue of natural arches and towers.


Bachelor of Science in Physics

Westminster College

Department of Physics



Chuck and Cathy Williamson Science Communications Fellow

University of Utah

Department of Geology and Geophysics


Sorenson Legacy Scholar

University of Utah

Women's Resource Center


Myriad Science Scholarship

Westminster College

Physics Department



How is the structural health of rock arches and towers affected by anthropogenic sources of energy?

Rock arches and towers are dynamic natural features that bend, sag, sway and shake in response to a variety of environmental forcings. My goal is to understand how arches respond to man-made energy sources, like helicopters, trains, highway noise, and even some earthquakes. We use seismometers to measure the resonant frequencies of rock arches and towers, and record their vibration response under exposure to controlled and uncontrolled anthropogenic energy sources. We compare the resulting vibrations to what the landform experiences naturally. The vibration velocity of the geologic landform can increase from 10-100 times its normal level, so we are trying to learn what that means for the landform's health. If the arch or tower doesn't experience instantaneous damage, what is the result of the landform experiencing higher vibrations over time?

We combine numerical modeling methods with laboratory and field methods to approach these questions, which means we get to work in a number of beautiful places around Utah. We are funded by the National Science Foundation and by the University of Utah.

Helicopter Infrasound

Why do certain arches and towers shake faster than usual when they are exposed to this high-power, low-frequency sound energy? What does this mean for their long-term stability?

Field Methods

We use broadband seismometers and nodal geophones to measure the vibrations of arches and towers, and infrasound microphones to measure the incoming sound energy.

Modal Analysis

We use 3D models to perform modal analysis on and determine material properties of these landforms.

Other Energy Sources

How do ground vibrations from trains and highway noise affect natural arches and towers?


Arches and towers have finite lifespans. How are humans changing that length of time?


Moore, J.R., P.R. Geimer, R. Finnegan, and J. Bodtker (2020). Between a Beam and Catenary: Influence of Geometry on Gravitational Stresses and Stability of Natural Rock Arches, Geomorphology. doi.org/10.1016/j.geomorph.2020.107244

Geimer, P.R., R. Finnegan, and J.R. Moore (2020). Sparse Ambient Resonance Measurements Reveal Dynamic Properties of Freestanding Rock Arches, Geophysical Research Letters, 47, e2020GL087239. doi.org/10.1029/2020GL087239

Moore, J.R., P.R. Geimer, R. Finnegan, and C. Michel (2019). Dynamic analysis of a large freestanding rock tower (Castleton Tower, Utah, USA), Bulletin of the Seismological Society of America, 109(5), 2125-2131. doi.org/10.1785/0120190118

Moore, J.R., P.R. Geimer, R. Finnegan, and M.S. Thorne (2018) Use of Seismic Resonance Measurements to Determine the Elastic Modulus of Freestanding Rock Masses, Rock Mechanics and Rock Engineering, 51(12), 3937-3944. doi.org/10.1007/s00603-018-1554-6


Finnegan, R., J.R. Moore, and P.R. Geimer. (2019) Vibration response of rock arches and towers to helicopter-sourced infrasound. Abstract 506450, presented at: American Geophysical Union Fall Meeting, San Francisco, CA, Dec 9-13.

Moore, J.R., P.R. Geimer, R. Finnegan, and C. Michel (2019) Modal Analysis of a Freestanding Sandstone Monolith (Castleton Tower, Utah). Abstract 505782, presented at: American Geophysical Union Fall Meeting, San Francisco, CA, Dec 9-13.

Geimer, P.R., J.R. Moore, and R. Finnegan (2019) In-Situ Nonlinear Elastic Response of Sandstone Landforms Under Dynamic Loading. Abstract 507404, presented at: American Geophysical Union Fall Meeting, San Francisco, CA, Dec 9-13.

Finnegan, R. (2018) Helicopter-induced resonance of Two Bridges, Bryce Canyon National Park. Poster presented at: Global Change and Sustainability Center Symposium, Salt Lake City, UT, Feb 15.



Earth Science Outreach and Education Endeavors

Williamson Fellow

K-12 Earth Science Education Outreach in Utah


Mathematics, Engineering, Science, Acheivement at Salt Lake Center for Science Education

Bryant Middle School

Develop hands-on Earth Science cirriculum for seventh-grade classes


Mentored freshman woman through an independent research project

General Outreach

Share our group's arches research with the general public


Contact Me