Geophysics Faculty Profiles

Bruce Douglas

Senior Lecturer and Co-Director of Undergraduate Studies.
Director, Indiana University Judson Mead Geologic Field Station

Research interests include the rheological properties of geological materials; stress and strain analysis; fault - fold interactions in field and analog settings; displacement transfer in fault zones; geologic field mapping; laboratory experimentation and measurement of rock fracture strength and time to failure; application of exploration geophysical methods to environmental problems.

At the present time my research is focused on developing an understanding of various deformation mechanisms that are active in the brittle and ductile portions of the lithosphere. Projects involve both laboratory and field based investigations; all projects typically combine either experimental or theoretical modeling with field or natural samples and site-specific data sets.

Michael Hamburger

Professor, Geological Sciences. Seismotectonics, volcanology, interplate deformation, Earth science education.

Major research interests are in seismotectonics, dynamics of earthquake and volcanic processes, and application of satellite geodetic measurements to geodynamic problems. He currently has active research programs in the subduction zone environment of the Philippine island arc, as well as in zones of continental extension in the Long Valley Caldera region of California and the intraplate environment of the central U.S. Major field research projects include: (1) analysis of earthquake distribution, focal mechanisms, and deformation patterns associated with subduction and intra-arc deformation in the Philippines; (2) study of crustal deformation using Global Positioning System (GPS) measurements near Taal volcano, Luzon, Philippines; (3) studies of seismicity and crustal deformation in the U.S. midcontinent (Wabash Valley seismic zone of southern Indiana and Illinois); (4) application of GPS measurements to study coupled tectonic and volcanic processes in the Long Valley Caldera of eastern California.

Kaj Johnson

Judson Mead Professor of Geological Sciences. Active deformation of the crust. Earthquakes. Earthquake cycle deformation. Fault friction. Mechanical modeling.

I am a geophysicist who works primarily with geodetic data and numerical and analytical modeling to investigate active deformation of the lithosphere. In particular, I study how deformation within plate boundary zones is accommodated by faulting and folding in the crust and viscous flow in the lower crust and upper mantle.

The types of research questions that motivate my current work and will continue to drive future research include:

  1. What physical processes are involved in the “earthquake cycle” at plate boundary settings consisting of relatively steady interseismic deformation punctuated by sudden earthquakes and rapid transient postseismic deformation?
  2. What controls the location and timing of large earthquakes on faults? To what extent can faults be characterized as consisting of locked patches that rupture unstably in large earthquakes and creeping patches that slide stably? Can we identify these patches and predict the location of future large earthquakes?
  3. How can observations from geology, geomorphology, seismology, and geodesy be combined to constrain a single mechanical model of crustal deformation over multiple time scales?
  4. How does short time-scale, recoverable elastic deformation transform into permanent, inelastic deformation in the lithosphere, and to what extent can this permanent deformation be recognized in the contemporary deformation field?

Gary Pavlis

Professor Emeritus of Geological Sciences. Seismic imaging by wavefield methods and tomography. Inverse methods. Geophysical data processing. Tectonics of convergent plate margins. Seismicity of the mid-continent.

My area of specialization is seismology, which is a branch of geophysics. My research can be described as a mix of experimental, theoretical, and computational work directed at addressing earth science problems. I have extensive experience with deployments of modern passive seismic array instruments, having been involved in a continuous series of field projects running from the late 1980s to the present.

The current example is the OIINK project. I am, however, still actively involved in the St Elias Erosion and Tectonics Project (STEEP). This large, collaborative group is currently involved in consolidation of diverse results from that project. I plan to continue work in that area as the USArray is planned to be deployed in Alaska in the next 5 years.

My computational work has been largely devoted to data processing challenges posed by modern passive seismic arrays.

My recent work has largely focused on seismic imaging. My students and I have developed a unique technology in a direct imaging method we call plane wave migration (see publications below). This method produces results similar to a 3D seismic reflection volume but using teleseismic earthquakes as sources. We are currently using this method to probe the entire upper mantle of the US using the Earthscope Transportable Array and to look at shallower structure in order to understand the origins of the Illinois Basin using data from the OIINK experiment.

Bob Wintsch

Professor Emeritus of Geological Sciences. Metamorphic Petrology, Structural Petrology, Tectonics, Geochronology

Research of Wintsch and students working with him spans several aspects of metamorphic geology, from diagenesis and low grade metamorphism in slaty rocks to high grade metamorphism and partial melting. Much of this research focuses on identifying the relationships between deformational and metamorphic processes, from the grain scale and pressure solution to the scale of terranes and terrane assembly.

Brian Yanites

Assistant Professor of Geological Sciences. Geomorphology

The Geomorphology and Landscape Evolution group studies how climate, tectonics, and rock type influence the processes and landforms that shape the Earth’s surface. Specific problems include the controls of rock strength and sediment transport on bedrock river morphology, the interaction of climate and topography during active mountain building, and the influence of landslides on river dynamics in seismically active regions. We approach these problems by integrating field and geochemical data with state-of-the-art numerical models. The implications of our work are broad, ranging from hazard mitigation and river management to the geologic evolution of a mountain system.