I am a geophysicist who measures sub-centimeter scale changes in the shape of the Earth caused by a variety of processes, both natural and human-induced, and my group develops models to understand the causes and consequences of this ground deformation.
My research provides new insight into the fundamental geological phenomena, but is also immediately applicable to such pressing societal questions as: Can we provide better warning before natural hazards like volcanic eruptions, landslides, or even earthquakes?
My primary observational tool is geodetic imaging, whereby image pairs are used to precisely measure positions on the Earth’s surface and their motion. Geodetic imaging encompasses several different methods including Interferometric Synthetic Aperture Radar (InSAR), stereoscopic images to measure topography, as well as the automated comparison of SAR and optical images via pixel tracking.
It is an exciting time for geodetic imaging because of the large number of satellites that can make these measurements — providing unprecedented spatial and temporal resolution and allowing us to make many discoveries.
To advance scientific understanding, my group combines geodetic imaging with multiple new datasets (particularly seismograms, GPS displacements, and multiple types of satellite data), develops numerical models, collects original data in the field by deploying seismometers and GPS stations, and collaborates with seismologists, geomorphologists, geochemists, petrologists, numerical modelers, glaciologists and structural geologists.
Some active projects include:
1. NASA project to study the impact of volcanic ash on the Earth System with collaborators in atmospheric science and geochemistry described here:
https://www.eas.cornell.edu/news/cornells-department-earth-and-atmospheric-science-received-14m-nasa-grant-study-global-effects
2. A NASA project to extend our global synthesis of volcano deformation that was presented here: https://link.springer.com/article/10.1186/s13617-018-0071-3 and include other types of remote sensing observations (including volcano temperatures and fumarole emissions) and develop numerical models of the deformation, thermal and gas evolution. The goal is to increase our understanding of how volcanic unrest is related to eruption by using a larger sample size of volcanoes that can be studied with satellite observations as opposed to just ground-based datasets.
3. An NSF project to combine GNSS and InSAR observations along with other data to study the geometry of incipient continental rifting in the SW African Rift.
4. I am part of the Science Team for the VenSAR radar instrument (built by NASA) on the European Space Agency mission EnVision to Venus (planned for launch in 2031-2032)
Also, I am interested in understanding the origins of human-caused ground deformation in New York (example publication for Ithaca) and across North America.
I am a member of Cornell's multi-disciplinary programs in Geophysics, Volcanology, and Remote Sensing and I am a faculty fellow with the Cornell Atkinson Center for Sustainability.
I use and help maintain the department's field geophysics equipment.
Here are some old pages that describe my previous work on earthquakes/tectonics, volcanoes, glaciers, Interferometric Synthetic Aperture Radar (InSAR), and PowellVolc: integrating various satellite observations of volcanic activity (outgassing, thermal, and ground deformation) to better characterize eruption precursors.
These pages are out-of-date but are included for historical purposes: Cornell Andes Project, old Cornell Geophysics & Active Tectonics Group, old Cornell Planetary Geology & Geophysics Group, old Cornell Remote Sensing Group