Andrew Jason Lloyd

Andrew Lloyd has been a Lamont Assistant Research Professor since 2023. His research focuses on imaging Earth’s internal structure, constraining the forces that act on and within it, and its response to these forces. To tackle these topics he uses novel inversion methods to leverage observations from seismology and geodynamic processes, like Glacial Isostatic Adjustment (GIA) - the viscoelastic deformation of the solid Earth as well as changes to its gravitational field and rotational axis in response to the evolving surface loads of the ice sheets and oceans. 

Andrew’s current research involves quantifying how GIA observations depend on mantle viscosity, rheology, and ice mass change as well as using these observations to directly image 3D mantle viscosity and constrain ice mass change. Extending these techniques, he leverages his codes to also quantify how a wider array of surface to near-surface mass changes predicted in Earth System Models induce regional changes in gravitation, rotation, and deformation. Overall this work contributes to improving constraints on regional sea level change and Earth rheology. Second, Andrew explores how seismic wave propagation is influenced by mantle heterogeneities in seismic wave speed and attenuation. Using this knowledge, he works to improve images of the Antarctic mantle constraining both the elastic wave speed structure and attenuation. These images help to estimate 3D mantle viscosity and temperature, which he uses in models of GIA and mantle convection. While the seismic images provide insights into geodynamic processes, seismically informed mantle convection modeling allows us to explore the imaged processes over millions to tens of millions of years. Finally, Andrew is working to build capacity at Lamont in Distributed Acoustic Sensing (DAS), which turns fiber optic cables into many hundred to thousands of sensors measuring ground motion. Over the last year, he has led three DAS deployments and built collaborations at Lamont-Doherty Earth Observatory and across Columbia University to utilize DAS to improve seismic hazard assessments, develop Smart City applications, and explore quantum communication.