HR: 0830h
AN: T51E-0200    [PDF]
TI: STIMULATED IR EMISSION FROM THE SURFACE OF ROCKS DURING DEFORMATION
AU: * Freund, F T
EM: ffreund@mail.arc.nasa.gov
AF: Friedemann T. Freund, SJSU/NASA Ames Research Center MS 242-4, Moffett Field, CA 94035-1000 United States
AU: Ouzounov, D
EM: ouzounov@eosdata.gsfc.nasa.gov
AF: Dimitar Ouzounov, SSIA/NASA Goddard Space Flight Center MS 902, Greenbelt, MD 20771 United States
AU: Wan, Z
EM: wan@icess.ucsb.edu
AF: Zhengming Wan, Yulin Zhang, Qincheng Zhang, ICESS/UC Santa Barbara, Santa Barbara, CA 93106 United States
AU: Zhang, Y
EM: zhang@icess.ucsb.edu
AF: Zhengming Wan, Yulin Zhang, Qincheng Zhang, ICESS/UC Santa Barbara, Santa Barbara, CA 93106 United States
AU: Zhang, Q
EM: qzhang@icess.ucsb.edu
AF: Zhengming Wan, Yulin Zhang, Qincheng Zhang, ICESS/UC Santa Barbara, Santa Barbara, CA 93106 United States
AU: Post, R
EM: rpost@mac.com
AF: Rachel Post, SJSU/Dept. Computer Science, San Jose, CA 95192-0106 United States
AU: Keefner, J
EM: john.keefner@sdsmt.edu
AF: John Keefner, NASA Ames Astrobiology Academy, Moffett Field, CA 94035-1000 United States
AU: Mellon, J
EM: chasemellon@juno.com
AF: Joshua Mellon, SJSU/Dept. Physics NSF-REU Program, San Jose, CA 95192-0106 United States
AU: Al-Manaseer, A
EM: akthem@email.sjsu.edu
AF: Akthem Al-Manaseer, SJSU/Dept. Civil Engineering, San Jose, CA 95192-0083 United States
AB: Studying the IR emission from rocks placed under stress may lead to a better understanding of the reported pre-earthquake "thermal anomalies", observed in mid-IR satellite images. Large blocks of granite and labradorite (45 x 30 x 7 cm3) were loaded in their center between two vertically oriented pistons (11.25 cm diameter). Smaller blocks of the same rocks plus gabbro (about 10 x 10 x 7 cm3) were loaded uniformly over their entire cross sections. We used a SATEC press (250 tons) and a BOMEN FT-IR spectrometer (3.3-14 micron), equipped with two black body sources (one at ambient temperature and another controlled at a higher temperature) for calibration. At 1 m from the samples, the spot size on the surface analyzed was about 5 cm in diameter. The blocks were loaded at a constant rate until failure. Typical runs lasted for 10-15 min. We monitored the IR emission from the front faces, which were either rough saw-cut or irregular broken. In the case of the large blocks the emitting surfaces were 20-25 cm from where the rocks were loaded. In the case of the smaller blocks the emitting surfaces were part of the rock volume that experienced increasing levels of stress and, at higher loads, underwent cracking and occasional spallation. We observed distinct changes in the IR emission spectra during press. The changes were specific of the rock and the loading geometry. They include a band at 11.7 micron, the position of which agrees with that of vibrationally excited O-O bonds, predicted to form when positive hole charge carriers, activated in the inner rock volume under stress, recombine at the rock surface.
DE: 3902 Creep and deformation
DE: 3904 Defects
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 4275 Remote sensing and electromagnetic processes (0689)
DE: 7209 Earthquake dynamics and mechanics
SC: Tectonophysics [T]
MN: 2003 Fall Meeting