Seth Stein uses global earthquake seismology for tectonic studies of plate boundary processes, intraplate deformation, present-day plate kinematics, and the rheology of the lithosphere. His goal is to obtain constraints on the nature and characteristics of dynamic processes in the Earth. He has recently focused on the mechanics of subduction zones and the relation between seismic and aseismic deformation in different tectonic environments including the boundary between the Nazca and South American plates and the central U.S. (New Madrid) seismic zone.
Emile Okal's research in hydroacoustics involves the nature and origin of sound propagating directly in the water mass of the ocean, after generation by both man-made explosions and natural phenomena such as earthquakes, landslides, volcanic eruptions, and undetermined sources within large icebergs. In this context, he presently directs a 3-year deployment of seismic stations on mega-icebergs recently detached from the Antarctic ice shelf. He has also studied the characteristics and origin of intraplate island volcanism, in particular at Polynesian edifices discovered through volcanoseismic swarms.
In addition, Okal studies the generation and propagation of tsunamis by large earthquake sources, and in particular the contribution of landslides to their genesis. These studies are carried out both theoretically, and from field work taking place either in the aftermath of large tsunamis, or through the interview of elderly witnesses of large, historical events. Okal is also contributing to the development of algorithms for real-time tsunami warnings, presently implemented at several observatories.
Seismological studies of the mantle are carried out by Craig Bina and colleagues, who investigate structures in the upper mantle, the lower mantle, and the region of the core-mantle boundary. Bina, Okal, and Stein, also study the source characteristics of deep and intermediate-depth earthquakes inside subducting slabs, with the goal of unraveling the mineralogical and thermal transformations which may accompany these events as well as the seismic energy budget at these depths.Back to top