Code 614.3 Branch Seminar: Tian-Chyi Jim Yeh

Department of Hydrology and Water Resources, The University of Arizona
Tian-Chyi Jim Yeh Professor Department of Hydrology and Water Resources, The University of Arizona, Tucson, AZ 85721. Email: yeh@hwr.arizona.edu. Abstract Three-dimensional maps of the Earth's subsurface distributions of water and related properties are necessary to improve our understanding and management of groundwater resources. Existing monitoring and characterization technologies cover only a small fraction of the subsurface, and their outputs cannot be used to reliably evaluate current and future water-availability issues. We are taking on the challenge of developing a system for subsurface simulation and imaging at the basin scale, the appropriate unit for water resources management issues. This will require detailed knowledge of the variability and characteristics of geologic formations at scales from meters to kilometers throughout the basin. Inverse modeling is a necessary tool for characterizing hydrologic properties of geologic media. Combined with geologic, hydrologic or geophysical tomographic surveys, it has become a viable, high-resolution subsurface characterization tool for meter-scale field problems. "Seeing" into a basin, however, requires significant scaling up and integration of these current high-resolution tools. This will demand unprecedented levels of computation and information processing. Besides, current methods relying on locally induced artificial stimuli (e.g., pumping at wells and ground penetrating radar) are much too costly and slow to provide dense coverage over a basin-size region. To overcome these impediments, we are exploring the possibility of exploiting natural stimuli as energy sources for large-scale hydraulic or geophysical tomographic surveys, supported with satellite monitoring technologies, modeling, simulation and other near real-time, networked information fusion technologies. Naturally recurring stimuli (e.g., lightning, storms, floods, volcanic activities, landslides, earthquakes, etc.) can provide a sufficiently varied distribution of excitations in time and space to obtain the requisite basin responses. Innovative approaches will be developed to continually reinterpret subsurface responses to these stimuli to gain increasing confidence in the evolving basin characterization. If you would like to meet with Prof. Yeh, please contact Dr. Bailing Li via e-mail at Bailing.Li@nasa.gov.