The scientific interests of the Geodesy and Tectonophysics Laboratory (GTL) in the Department of Geosciences at Virginia Tech involve elucidating the physical processes that initiate, maintain, and evolve plate tectonics. The interaction of tectonic plate can result in devastating volcanic eruptions and earthquakes, implications of which my research can have immediate and long-term impacts to mitigate hazards. Currentling GTL research addresses these topics by investigating four fundamental questions:
1) How and where is strain accommodated during active tectonics?
2) What balance of forces drive surface deformation from tectonic processes?
3) What are the feedback mechanisms between tectonic deformation, volcanism, and active
seismicity towards a more resilient society?
(4) What are the physical mechanisms driving vertical land motions in regions affected by sea-level
GNSS site in Natron Rift, Tanzania
We investigate asthenosphere-lithosphere interactions in continental rift settings. In order to study the asthenosphere- lithosphere interactions, we uses the NSF CIG community code ASPECT. We create 3D models of a regional mantle flow with distinct independent initial temperature conditions. This is the first 3D regional the lithospheric modulated convection model developed with ASPECT, which is driven temperature perturbations that arise from variations of lithospheric thickness. We also produce a convection model developed with ASPECT based on the conversion of a shear wave velocity model into temperature, which generates buoyancy due to temperature anomalies. In order to validate the mantle flow fields, we compare them with independent observations such as GPS velocity and seismic anisotropy.
WHAT IS THE ROLE OF UPPER MANTLE FLOW ON LITHOSPHERIC DEFORMATION?
REDEFINING EAST AFRICAN RIFT SYSTEM KINEMATICS
Evidence from geologic mapping as well as Quaternary volcanism and sedimentation indicate Madagascar is tectonically active. We are now using GNSS data collected over up to 10 years to investigate if Madagascar is breaking up. Or is Madagascar moving with the Somalian plate?
COLLABORATIONS AND AFFILIATIONS
LITHOSPHERE-ASTHENOSPHERE INTERACTIONS AND LITHOSPHERE DYNAMICS USING MODERN CYBERINFRASTRUCTURE
We aim to test lithosphere-asthenosphere interactions and lithospheric dynamics with new EarthCube cyberinfrastructure called BALTO (Brokered Alignment of Long-Tail Observations. We will access a suite seismic tomography and other models from IRIS to use as initial conditions in geodynamic models run with ASPECT. Model output will be compared with independent observations to improve our understanding of lithospheric processes.
Example undergraduate projects 1) test fault geometry models for recent earthquakes, 2) test properties of rifts needed to explain previous earthquakes on local structures, 3) implemenet modern tools for cyberinfrastructure development to evaluate edge-driven convection material paramaters, and 4) development of transient detection algorithms.
Sea-level rise is a critical process creating hazards on Earth's population. Quantifying vertical land motions in regions experiencing effects from sea-level rise remains an important topic towards resilience to the effects of sea-level rise. We are embarking upon a kinematic and geodynamic study of the Chesapeake Bay of the North American Atlantic Coast in collaboration with the USGS and NOAA to (1) characterize vertical land motion with millimeter precision and (2) conduct numerical modeling to decipher the signals (fingerprints) that comprise the vertical land motions using a newly funded USGS grant (co-PI).
QUANTIFYING AND ASSESSING VERTICAL LAND MOTIONS IN THE CHESAPEAKE BAY
HOW DO VOLCANO-TECTONIC INTERACTIONS INFLUENCE EARLY-PHASE RIFTING?
In this project, we are using the Natron Rift of the East African Rift System as a natural laboratory to study early phase rifting. The active volcano Ol Doinyo Lengai is adjacent to the active border fault, the Natron Fault. We are using GNSS observations, InSAR, and numerial modeling to investigate the role of volcano-tectonic interactions in strain accommodation across the Natron Rift.