GEOLOGICAL SCIENCES AT BROWN UNIVERSITY
Seismology/Geodynamics

In the past few years at Brown, the effort to understand flow in the Earth's mantle has included several oceanographic research cruises to the Pacific, Indian, and Atlantic Oceans, the deployment of arrays of seismometers across eastern and central North America and the East Pacific Rise, and the development of sophisticated numerical simulations of three-dimensional flow and wave propagation. One particular focus has been the generation of melt by upwelling beneath mid-ocean ridges and its subsequent migration to the surface at the ridge axis to form new seafloor. Seismic experiments, gravity measurements, side-scan sonar, and multi-beam bathymetry all provide observational constraints for the attempt to develop theoretical models that explain the segmentation of the ridge system, the thickness and composition of the oceanic crust, and the formation of median valleys and axial, topographic highs.

Another important focus is the use of seismic velocity anomalies and anisotropy to help map flow in the mantle. Seismic anisotropy in the upper mantle is likely caused by shearing due to plate motions and convection, with additional influence from partial melt in certain regions. With the aid of theoretical models of convection and wave propagation, we are studying mantle structure and flow near subduction zones and mid-ocean ridges, beneath continents, and at the core-mantle boundary. Unique data sets of seismic waveforms have been acquired in the TUCAN, GLIMPSE, MELT, MOMA (Missouri to Massachusetts), NOMAD and FLED (Florida to Edmonton) Experiments. These examples show how integration of theory and observation is fundamental to the philosophy of our group. Our mode of research emphasizes collaboration. Students typically work with more than one of our faculty, and we enjoy an interactive environment that includes seminars, informal research talks and lots of discussion.

Our mode of research emphasizes collaboration. Students typically work with more than one of our faculty, and we enjoy an interactive environment that includes seminars, informal research talks and lots of discussion.