Tectonics and dynamics of accretionary prisms in subduction zones, earthquake source mechanics and faulting processes, kerogen maturation and oil migration during maturation of organic rich shales, and nucleation and crystallization processes are some major questions in geophysics today. The composition, state of materials, and interactions between the constituents in such areas are important to understand the driving forces and to facilitate their prediction. Since direct observations, for example in boreholes, are not always feasible, seismic information is often our only source of information. To make inversions from seismic to rock materials properties more reliable, our focus should be on characterizing the dependencies between seismic and rock physical properties. This study is aimed at providing the geoscience community with a method to quantify microstructure and rock properties in terms of elastic impedance. Microstructural characterizations made with Acoustic Mapping (AM) are based on quantifiable impedance variations. These quantitative measurements will allow us to directly relate impedance microstructure to seismic wave propagation in rocks. Main impact areas of the study will be to develop a new method to express microstructure in terms of elastic impedance, measure, possibly for the first time, elastic properties of clay minerals and elastic impedance changes associated with cementation and crystallization, and understand and model the correlation between seismic and rock physics properties. The eighteen-month project is divided into two parts. Research in the first part will be to calibrate the acoustic imaging techniques with earth science relevant materials. Although seismic properties and acoustic mapping of rocks have a common working principal, potential applications of AM to rock physics remain to be exploited. Currently, AM is used almost entirely for non-destructive evaluation of defects in man-made and in biomedical materials. The second part will be devoted t analyzing representative samples and comparing impedance microstructures with seismic signatures. This project will allow the investigator to develop acoustic mapping techniques. Professionally, it will broaden her analyses and modeling skills and enhance prospects for progress, for example towards a faculty or senior research position. The project is a joint collaboration between German (Dr. Burkhard, Prof. Arnold) and US research scientists (Dr. Meike, Dr. Thomas) that will allow the PI to define a long-term project. Research associates at Stanford University are not granted PI status. This proposal gives the PI an opportunity to apply for research funds to develop a project in an area of tremendous potential.
