Geophysicists aim to understand the dynamics of the Earth through research on the physical processes, properties, and structure of the planet on which we live. The Geophysics group at UC Davis is involved in a diverse spectrum of research activities including geodynamics, marine geophysics, seismology, paleomagnetism, geodesy, natural hazards, and tectonics. In their research, faculty and students in geophysics use theoretical modeling, computer simulations, data analyses, laboratory experimentation, and land and marine field observations.
Magali Billen. Most of the interior structure of the Earth's mantle, including its geophysical and chemical properties can not be measured directly. Instead, these properties are inferred from a combination of indirect measurements, laboratory experiments and numerical models. My primary research interest focuses on using numerical models to test hypotheses about the spatial and temporal variations in the physical properties of rocks within the earth. This is done by comparing predictions from numerical models to observations made at the earth's surface from geophysics (e.g. topography, tomography, strain-rates), and geochemistry (e.g. temperature and pressure of melting, water content, age of deformation) and geology. In using geodynamic models in this way, examples of how the Earth has deformed in the past provide an important guide to interpreting model results. This leads me to my second research focus, plate tectonics, or more specifically, making geophysical observations which help to constrain both when and how tectonic plates have moved and deformed.
Louise Kellogg. The solid Earth is in a continual state of deformation both in the deep interior as well as at its surface. I am interested in both "why" and "how" this deformation occurs. One major component of my research is to use computers calculations to study convection in the deep mantle. This work includes studies of the evolution of mantle plumes, models of thermo-chemical convection near Earth's core-mantle boundary, as well as investigations of mantle stirring and mixing over geologic time. Mantle convection is also important in that it drives plate tectonics, deforms the crust, and generates earthquakes. Deformation of the Earth's surface is the second major area of my research. My graduate students and I have been using the Global Positioning System (GPS) satellite network in conjunction with numerical models to understand the way the Earth's lithosphere deforms and how faults break.
James McClain. I exploit a variety of geophysical techniques, in conjunction with geological observations, to understand the structure and evolution of the Earth's crust. I examine problems using seismic refraction and earthquake data, as well as magnetic and gravity measurements. Much of my work has focussed on the mid-ocean ridges, with particular emphasis on how magma is stored and how this affects hydrothermal systems along the axis of mid-ocean ridges. We at UC Davis were the first to show that ridge magma chambers must be narrow, and that hydrothermal systems are accompanied by extensive microseismicity. Most recently we are using these geophysical tools to study transform faults as well as underwater volcanoes that erupt near mid-ocean ridges. With my students, I have recently moved onto the continents, with projects in the Monterey Bay, the central California coast, and, in the near future, northeastern California.
John Rundle. My research is concerned with the dynamics of complex systems, for the most part in the geosciences. For over thirty years, my research has focused on using statistical physics to understand the physics of earthquakes and other driven threshold systems. Mathematically, these systems are characterized by phase transitions, both first (nucleation) and second order types. The dynamics of these systems can be understood by the use of field theories developed in other areas of physics, including particle physics and cosmology.
I have a particular interest in the development of methods for earthquake forecasting based on studies of chaos and complexity in driven nonlinear systems, as well as on the use of realistic, large scale numerical simulations. More recently, I have developed an interest in viewing crashes in economic and financial systems as a kind of .Econoquake. that might be understood by analogy to earthquakes and other first order (nucleation) phase transitions.
Sarah T. Stewart. Planet formation and evolution with focus on collisional processes, including giant impacts and impact cratering. Laboratory measurements of the equation of state and rheological properties of planetary materials using shock wave techniques. Experimental and computational studies of impact processes to interpret the formation, resurfacing history, physical properties, and internal structure of planets and small bodies.
Kenneth Verosub. In recent years, the focus of my research has expanded from studies of magnetostratigraphy, tectonic rotations and geomagnetic field behavior to environmental magnetism, a new field of geophysics that uses the magnetic properties of soils and sediments as tracers of environmental and paleoclimate processes. At the present time, the paleomagnetism group is working on samples collected in China, Russia, Israel, Hungary, Argentina, New Zealand, Australia, Tahiti, South Africa, Canada and Antarctica as well as on samples taken from cores from all of the world's oceans and several of its major seas and lakes. In many cases, these projects involve travel to distance lands and close collaboration with scientists in other countries. Students who join the paleomagnetism group will work with state-of-the-art equipment in one of the best-equipped paleomagnetic labs in the country. For most projects only a basic physics and geology background is needed.
Donna Eberhart-Phillips. Modelling of three-dimensional seismic velocity structure and material properties; and seismotectonic analysis of active deformation. Motivated to integrate 3-D velocity and attenuation models with other geophysics and to use 3-D velocity models to understand the effects of heterogeneous material properties, to extend beyond simply interpreting crustal structure. Current research efforts have focused on New Zealand and Alaska, with emphasis on understanding subduction processes and the transition from subduction to collision. Recent work with imaging 3D attenuation structure is valuable for interpreting tectonic processes that involve fluids, and also has application to engineering response spectra.
John Naliboff. Computational geodynamics, geophysics, tectonics and structural geology. My research focuses on determining the relative influence of plate driving forces and lithospheric rheology on tectonic deformation patterns over a wide range of spatial and temporal scales. To investigate the origins of observed deformation patterns, I use forward modeling of lithospheric and mantle convection processes to constrain existing or newly obtained structural and geophysical observations. Active projects include investigations of the global lithospheric stress field, outer rise deformation in the Tonga subduction system and continental extension in the North Atlantic and Gulf of California. I am also beginning projects associated with the development and testing of long-term tectonics software capable of simulating high-resolution, 3-D lithospheric deformation processes.
M. Burak Yikilmaz. Structural geology, tectonics, geodynamics, and geoinformatics. Research interests include fault interaction and crustal deformation using geodetic data and numerical simulations, application of machine learning techniques to Earth Sciences with an emphasis on classification and anomaly detection. Also interested in 2D/3D data visualization, statistical data analysis, and low cost virtual reality systems. Primary collaborator on the Augmented Reality Sandbox project (https://arsandbox.ucdavis.edu). Currently working with informal science education centers on an NSF funded project to improve STEM (Science Technology Engineering Math) education by providing 3D visualizations of the major lakes and reservoirs of the world to enhance public awareness and increase understanding and stewardship of freshwater lake ecosystems, habitats, and earth science processes.