Using the highest-resolution and longest-period Love wave phase velocity maps that have been developed for the Continental U.S., we are investigating regional variations in Radial anisotropy in the upper mantle.
Using body-wave tomographic methods, we have been developing high-resolution images of relative velocity variations in the mantle beneath old oceanic lithosphere.
We are using shear-wave splitting of teleseismic SKS phases to characterize mantle deformation beneath greenland, taking advantage of sophisticated methods to analyze the large parameter space and constrain depth-dependent anisotropy in the region. We explore the origins of depth-dependent anisotropy in the context of the region's tectonic history.
We showed for the first time that measurements of Rayleigh wave phase and amplitude (and phase velocity) are affected by interference from major-arc overtones- the interference is best seen at epicentral distances greater than 120 degrees.
Empirical proof of the phenomenon, through analysis of measurements made on spectral-element simulations and real data recorded by USArray, is shown in our manuscript here.
We have more generally explored the phenomenon of overtone interference rigorously, with the goal of better understanding the origin of aspects of the interference pattern
and the extent to which different factors effect it. We have shown that the relative excitation of different overtones can prove to be a powerful predictor of the strength of interference, and can explain the distribution of error in Rayleigh wave phase velocities as a function of epicentral distance.
In a study in GJI , we showed that considering the relative excitation of overtones and the FM, as well as the relative group and phase velocities of the overtones and FM, can explain well the location, amplitude, and wavelength of interference.
We were able to leverage variations in path-integrated group velocities to conduct Love-wave tomography of the United States, as is shown in a study in GRL here.
We are currently extending our understanding of overtone interference to examine the extent to which it may be present on other planetary bodies with current or future planned seismometer presence (e.g. The Earth's Moon, Mars, Venus, and Titan)
Understanding the properties of hydrated mineral phases at depth can yield powerful insight into the bulk properties of Earth structure in geodynamically complex settings such as the hydrated layers overlying subducting slabs. Using first-principle ab initio simulations of crystal structure allows us to model the equations of state, detailed crystal structure, and elasticity of these phases. The latter observation also allows us to understand the anisotropy of these phases. Results from these studies were published here and here. I was supervised by Professor Mainak Mookherjee during the course of this work.