Seismic waves are a preferred method for probing the interior of the Earth. Materials making up the Earth are expected to have directionally dependent properties (aka seismic anisotropy) that affect the speed and polarization of seismic waves going through them. Anisotropy can arise from a variety of mechanisms, from layering and cracks to systematic crystal lattice alignment. An ability to detect, describe and interpret anisotropic properties revolutionized global seismology in the last two decades, offering a way to observe directions of movement of large rock masses within Earth’s interior and to map past deformation episodes.
In this presentation I will illustrate the use of seismic anisotropy observations in addressing three questions of various scale and geologic timing. I will use observations of birefringence in shear waves to support an argument for ongoing upper mantle flow between the Pacific and the Caribbean. I will demonstrate an application of methods based on compressional-to-shear converted waves for imaging deformation zones preserved in the Earth’s crust for hundreds of millions of years. I will conclude with a discussion of a systematic survey of anisotropic properties in a continent that offers a new way of mapping the bottom of the lithosphere.
Vadim Levin studied methods of geophysical exploration at the Moscow Institute of Oil and Gas in USSR, and subsequently received a PhD in Seismology from Columbia University in New York. From 1995 through 2002 he worked as a researcher at the Department of Geology and Geophysics of Yale University in New Haven, CT. Since 2002 he holds a faculty position at the Department of Earth and Planetary Sciences of Rutgers, the state university of New Jersey.
Professor Levin studies the interior of the Earth using observations of seismic waves. He specializes in investigations of directional variation (anisotropy) of seismic properties in the Earth, and the processes that may be responsible for it. Over the course of his career he collected seismic data in Europe, Asia, North and Central America. He served in editorial capacity at international journals “Tectonophysics” and “JGR Solid Earth” and participated in the governance of the Incorporated Research Institutions for Seismology (IRIS) consortium. He authored and co-authored over 80 peer-reviewed publications.
Department of Earth and Planetary Sciences, Rutgers