HR: 1340h
AN: T23A-0569    [Abstracts]
TI: The temperature during the high speed friction experiments estimated by ESR signals in quartz
AU: * Usami, T
EM: s04pm04@physics.dap.ous.ac.jp
AF: Department of Applied Physics Okayama University of Science, 1-1 Ridai, Okayama, 700-0005 Japan
AU: Toyoda, S
EM: toyoda@dap.ous.ac.jp
AF: Department of Applied Physics Okayama University of Science, 1-1 Ridai, Okayama, 700-0005 Japan
AU: Mizoguchi, K
EM: shima@kueps.kyoto-u.ac.jp
AF: Department of Geology and Mineralogy Division of Earth and Planetary Sciences Graduate School of Science Kyoto University , Kitashirakawa-Oiwake Sakyo-ku, Kyoto, 606-7502 Japan AU: Shimamoto, T
EM: shima@kueps.kyoto-u.ac.jp
AF: Department of Geology and Mineralogy Division of Earth and Planetary Sciences Graduate School of Science Kyoto University , Kitashirakawa-Oiwake Sakyo-ku, Kyoto, 606-7502 Japan AU: Hirose, T
EM: hirose@erdw.ethz.ch
AF: Geologisches Institut, ETH-Zentrum, Zurich, CH-8092 Switzerland
AB: ESR (electron spin resonance) dating method has been developed to obtain ages of quaternary geological events using calcite, aragonite, hydroxyapatite, and quartz. In natural quartz, paramagnetic (ESR sensitive) defects such as Al center (an Al atom replacing a Si, trapping an electronic hole) and Ti-Li center (a Ti atom replacing a Si, trapping an electron together with Li$^{+}$ as a charge compensator) are stable for the geological time scale while they decay on heating according to the thermal activation processes. In the present study, we use these ESR signals as indicators of temperature during the high speed friction experiments. The present experiment will also tell the conditions of faulting which completely zero the ESR signals, which is necessary for ESR dating of faulting to work. The gamma ray irradiated quartz grains of 0.5 to 1 mm were sandwitched by two gabrro columns of 25 mm in diameter with a tephron sleeve. The friction expereiments were performed with a load of 30 kg and with speeds of 75 to 300 rotation per minutes. After removing the columns, the crushed quartz powder was divided into three parts, outer, intermediate, and inner parts. ESR measurements were performed by an ESR spectrometer, JEOL PX-2300, at 83-87K, with a microwave power of 5 mW, and with an modulation amplitude of 0.1 mT. The estimated temperatures are higher for outer part where the frictional speed is higher while lower for inside, with systematic difference for different ESR signals, when assuming that the temperature was constant during friction experiments. The temperatures will be estimated again, in the presentation, with considering the temperature change with time while friction experiments, also with taking into account the results of heating experiments.
DE: 8010 Fractures and faults
DE: 8123 Dynamics, seismotectonics
DE: 4860 Radioactivity and radioisotopes
DE: 7209 Earthquake dynamics and mechanics
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting