UofL Highlights
Microstructural Analyses of Gouge from the San Andreas Fault Observatory at Depth (SAFOD) Borehole in Relation to Fault MechanicsThe rock material caught in between the two sides of a geologic fault is known as fault gouge. In general appearance, fault gouge is like crushed rocks that have been cemented back by their own finer powder. Depending on the conditions of faulting such as pressure, temperature, stress, and fluid flow, fault gouges include microstructures such as intricate network of sliding surfaces that separate regions with a wide range of fragment sizes. In addition, the gouge microstructures are often associated with suite of exotic minerals. The microstructures and chemical variation are believed to be the result of sudden (earthquake) and slow (creep) movement on the fault over long periods of time. The main goal of this collaborative project is to extract the information content of the fault gouge using analytical and imaging techniques. We have proposed to investigate gouge microstructures from the San Andreas Fault Observatory at Depth (SAFOD) drill cores and use the information to test the existing models of earthquake faulting. The SAFOD cores have been brought to the surface over the past 3 years from depths of a 3.5Km drill hole that penetrates the active parts of the San Andreas Fault in south central California. This project directed by Jafar Hadizadeh, is funded by the NSF and awarded to the University of Louisville in the amount of $489,000 over three years. The project operates with collaborators from University of Oslo Norway, University of Padova Italy, and Georgia State University, as well as University of Tokyo Japan. The collaborating team has also forged close ties with the Geoscience Department at the Joseph Fourier University in Grenoble France. The SAFOD is one of the four components of a 5-year, $219 million nationwide Geoscientific effort known as the EarthScope. EarthScope provides freely accessible data and data products from thousands of geophysical instruments that measure motions of the Earth's surface, record seismic waves, and recover rock samples from depths at which earthquakes originate. EarthScope is unique in the history of the US basic Earth science research not only by its budget, but also due to its integrated science, education outreach and public awareness campaign. See http://earthscope.org for further information.
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