John E. and Hazel S. Smits Professor of Geophysics; Director, Seismological Laboratory

Present-Day Geodynamics

We use the wide variety of geophysical constraints that we have of the present day earth (plate motions, geodesy, gravity, seismicity and seismic structure, etc.) to better understand the forces and processes acting to drive and resist plate motions and mantle flow. We exploit the high fidelity of geophysical observations with high-resolution forward and inverse models. Increasingly, we use constitutive relations (rheology laws) that are the same or similar to those found in the laboratory.  

Historical Geodynamics

We explicitly link time-dependent geodynamic models to the geological record. These approaches complement those of present day geodynamics in that we link and test models against those data traditionally used in geophysically-orientated geodynamic models. Examples of the complementary data include time-dependent plate motions, the record of stratigraphic deposits onshore and offshore, and the record of volcanism. This approach allows us to better understand geodynamic processes while providing a physical under-pinning of the evolution of the earth. 

Deep Earth Dynamics

The lower mantle plays a fundamental role in the thermal and chemical evolution of the planet. Much of the heat and heat producing elements ultimately driving continental drift and plate tectonics probably reside in the lower mantle and the boundary between the core and mantle is a primary interface within the deep interior and has a fundamental influence on the magnetic field, the cooling of the planet, and volcanism at the Earth's surface. We carry out a wide variety of studies using geodynamic models closely integrated with seismology and mineral physics in close collaboration within the Seismological Laboratory.