Brief note on effects of thermal pulses on elastic moduli and Q of rock

Preliminary results of a current experimental study on relationships between elastic moduli, internal friction (Q^?1) and rock structure are compatible with lunar in situ observations which indicate that mechanisms which lower the elastic moduli of rock need not contribute significantly to the internal friction. In terrestrial rock samples which were thermally pulsed in vacuum, elastic moduli decreased andQ's increased. These results imply that the thermal pulsing induces damage such as microcracks (which lower the elastic moduli), eliminates crack surface contaminants and may destroy other possible sites of internal friction such as grain boundary mechanisms and hydrous minerals (increasingQ).