HR: 0800h
AN: T51B-1334    [Abstracts]
TI: Stress-Rate-Dependent Seismo-Electrodynamcis of Non-Quartz Bearing Rocks
AU: * Lau, B
EM: bwslau@yahoo.com
AF: San Jose State University, Department of Physics, San Jose, CA 95192-0106 United States
AU: Takeuchi, A
EM: takeuchi@curie.sc.niitaga-u.ac.jp
AF: Niigata University, Department of Chemistry, Niigata, 950-2181, Japan
AU: Freund, F T
EM: ffreund@core2.gsfc.nasa.gov
AF: San Jose State University, Department of Physics, San Jose, CA 95192-0106 United States
AU: Freund, F T
EM: ffreund@core2.gsfc.nasa.gov
AF: NASA Goddard space Flight Center, Planetary Geodynamics Laboratory, Greenbelt, MD 20771 United States
AB: Seismo-electromagnetic phenomena require the existence of mobile charges and potential differences. We demonstrate an experiment that produces two currents flowing out of a stressed rock volume. The currents are generated by application of stress on quartz-free gabbro. The magnitudes of the currents are stress-rate dependent. Applying stress rates that span over 6 orders of magnitude, we find that the currents show distinctly different behaviors in two stress regions. At the beginning of loading, the currents increase rapidly, but a sharp burst of current is observed when the stress rates become high. This is followed by an apparent saturation. The highest currents are reached at relatively low stresses and high stress rates. These observations are consistent with the generation of mobile charges that in turn produce potential differences. Understanding these currents leads to characteristic charge behavior that might be detectable prior to major rupture events in the Earth's crust.
DE: 3904 Defects
DE: 3914 Electrical properties
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 8164 Stresses: crust and lithosphere
DE: 8168 Stresses: general
SC: Tectonophysics [T]
MN: Fall Meeting 2005