Research
My research interests include developing sophisticated numerical forward models and performing probabilistic (e.g., Bayesian) inversions aimed at understanding the evolution, tectonics, volcanism, and habitability of planetary bodies. You can find more details on my research projects below.
LUNAR EVOLUTION
(coming soon)
Enceladus: Saturn's Geologically Active Moon
Over the course of its elliptical orbit, the moon Enceladus is squeezed unevenly by Saturn's gravitational pull and deforms from a spherical shape into a football shape and back again. This cyclic stress causes so-called "tidal heating" in Enceladus and dissipates enough energy to maintain what is believed to be a global ocean underneath the moon's icy crust.
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Geologic Activity at Enceladus
At Enceladus's south pole, a large number of jets spray icy particles out from a set of jagged, 150-kilometer-long faults—known as the tiger-stripe faults. This ejected material coalesces above the moon's surface to form a plume. The plume above Enceladus’ south pole varies in intensity, waxing and waning in strength, with two notable peaks in emission during the moon’s 33-hour orbit.
To better understand mechanisms controlling jet activity, I developed a sophisticated numerical (finite-element) model to simulate strike-slip motion along Enceladus’ faults. These models consider the role of friction, which causes the amount of slip on the faults to be sensitive to both compressional and shearing stresses. The numerical model was able to simulate slip along Enceladus’s faults in a manner which matched the variations in plume brightness as well as spatial variations in surface temperature, suggesting that the jets are controlled by strike-slip motion over Enceladus’ orbit.
To explain the apparent correlation between jet activity and strike-slip motion, we theorize that variations in the flux of plume material is due to “pull-aparts” in the faults—bent sections that open under broad strike-slip motion.
Bottom: image adapted from our 2024 Research Article
Read more in our 2024 paper in Nature Geosicence
Characterizing Enceladus's Lumpy Crust
Enceladus's crust varies in thickness from ~50 km near its equator to ~10 km at the poles. These variations in thickness induce a variation in the response of the crust to tidal forces, which can be potentially be measured using advanced radar techniques (e.g., inteferometric radar or InSAR).
I developed a methodology to recover lateral variations in crustal thickness at Enceladus using potential measurements of elastic strain over the surface of the moon. This approach involves initially recovering crustal thickness based on the expectation that local thickness is inversely proportional to tidal strain (i.e., Hooke’s law), then iteratively updating thickness values to minimize differences between a measured crustal strain field and that produced by numerical models. The newly developed methodology enables determinations of thickness with an accuracy of ~2 km across the crust.
I also use numerical models to understand whether inferences of mean crustal thickness derived from Enceladus' response to tidal forcing are sensitive to the presence of 3D structure (e.g., faults, thickness variations). Results from numerical models demonstrate that tiger stripes produce highly localized deformation near their tips and have minimal impact on the moon’s predicted long-wavelength tidal response. By contrast, regional thinning of the crust near the South Pole creates a long-wavelength displacement pattern that can bias estimates of mean crustal thickness by up to ~20%.
Read more in our 2023 paper in JGR: Planets our 2024
paper in Geophysical Research Letters, and our 2024 paper in
JGR: Planets
Bottom: image of Enceladus enmeshed in Saturn's E-Ring
Characterizing Degassing Structure over Volcanic Systems
Volcanic system degassing naturally elevates ambient CO2 over vast areas. Volcanoes also exhibit a diverse array of geologic structures that influence the spatial and temporal character of degassing near the surface. As such, volcanic systems are an excellent tool to study interactions between the Earth's atmosphere and solid interior over several several spatial and temporal scales.
Current Unmanned Aerial Vehicle (UAV) survey methods enable high-throughput gas monitoring but cannot readily recover both magnitudes and spatial patterns of flux sources across multiple spatial scales. We present an inverse approach to compute ground flux distributions from UAV-based concentration measurements and probe the technique's capacity to evaluate flux for varying simulated concentration noise amplitudes, altitudes of data acquisition, and lateral spatial extents of measurements. To demonstrate proof of concept, we deploy our inversion technique to map ground flux distributions at degassing sites at Turrialba and Rincon de la Vieja Volcanoes, Costa Rica.
Read more in our 2024 paper in JVGR our upcoming paper in JGR: Solid Earth